Dermatology: Practical and Conceptual


DERMATOLOGY PRACTICAL & CONCEPTUAL
www.derm101.com

Review  |  Dermatol Pract Concept 2012;3(2):4 13

Introduction

A Bernard Ackerman always had a “dream” that a diction-

ary would be created for dermatopathology (and dermatol-

ogy) so that these fields could better communicate with one 

another, in one “language.” He felt that until a real diction-

ary came into being neither would be authentic branches 

of knowledge. He also felt that this dictionary would serve 

pathology as well. Many tried to complete this “project” (in 

Philadelphia, New York, and elsewhere) but none succeeded. 

Bernie considered Morris Leider’s 1976 dermatology diction-

ary a very limited one for many reasons. Bernie’s own efforts 

with Almut Böer, M.D. in the journal, Dermatopathology: 
Practical & Conceptual used an “extended discussion of 
each word.” They managed to get through the “A’s” (over a 

two year period) and attempted to show others how a dic-

tionary should be completed. They encouraged others (using 

their model) to continue this work.

This compendium of words is not meant to be “original” 

nor is, it a “dictionary” as defined. The Oxford Dictionary, 

second edition revised, says “dictionary: a reference book con-

taining an alphabetical list of words with information given 

for each word, usually including meaning, pronunciation, and 

etymology.” This work is essentially based on Bernie’s opin-

ions about words. My task has been to “pluck” the words, 

ideas, and concepts out, organize them, rewrite some and add 

some of my own. Discussions of words have been taken from:

•	 All his glossaries from 1978-2010—the glossaries have 

been the most useful

•	 All his books from 1978-2010 (the material “outside” the 

glossaries)

•	 The journal, Dermatopathology Practical & Conceptual 

(with Almut Böer, M.D. and other authors) and Bernie’s 

material from other places, (i.e., Indianapolis meetings, 

Palm Springs meetings, AAD meetings, ISDP, ASDP, as 

well as the material from the Institute of Dermatopathol-

ogy at Jefferson in Philadelphia and the Ackerman Acad-

emy in New York, etc.) The Journal has been extremely 

useful. Its use accounts for why there are so many words 

in the “A’s” compared to other letters since this was the 

only letter for which definitions were done. In summary, 

the glossaries and “The Journal” were the most useful.

In addition the reader should keep in mind the following: 

Whenever I say Bernie’s works I am including his coauthors, 

if any. A portion of the material is copied verbatim from Ber-

nie’s material. I fully acknowledge that. (However, this is a 

tribute to Bernie.) Its essence and beyond is “Ackermanian.” 

Much of the material has been paraphrased from Bernie’s 

works. A small amount of material comes from “others” and 

has been paraphrased or rewritten. (i.e., epidermotropism, 

neurotropism). Some of Bernie’s “words” have been rewrit-

ten by me in order to update the material as old ideas were 

discarded and new ones came to fruition (i.e., the infundibu-

lum is epidermal). One change in a concept usually leads to 

many changes in the meanings of a word or many words. I 

hope my updates of Bernie’s “definitions” which I decided to 

do have stayed true to Bernie’s ideas and opinions (mine are 

very similar). Some of the discussions of words are long and 

Dermatopathology: an abridged compendium of 
words. A discussion of them and opinions about 

them. Introduction and Part 1
Bruce J. Hookerman, M.D.1

1  Dermatology, St. Louis, Missouri, USA

Citation: Hookerman BJ. Dermatopathology: An abridged compendium of words. A discussion of them and opinions about them. 
Introduction and Part 1. Dermatol Pract Conc. 2013;3(2):4. http://dx.doi.org/10.5826/dpc.0302a04.

Copyright: ©2013 Hookerman. This is an open-access article distributed under the terms of the Creative Commons Attribution License, 
which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Corresponding author: Bruce Hookerman, M.D., 12105 Bridgeton Square Drive, St. Louis, MO 63044, USA. Email: bjhookerman@att.net.



14 Review  |  Dermatol Pract Concept 2012;3(2):4

rambling and repetitious (i.e., in-situ). The reason for this is 

that in many cases (especially in the “A’s”) they follow Bernie 

and Almut’s method and definitions. Also, some discussions 

are pieced together from multiple sources. I hope this piecing 

together of a discussion of a word from various Ackerman 

sources has not lead to confusion.

The Oxford, Webster, and other well known dictionaries 

are accepted as “definers of the English language.” They do 

not differ very much. However, among the different “schools 

of dermatopathology” there are large differences in the 

usage, understanding, and the meaning of words (much less 

so for dermatology.) I feel this is driven by differences in 

concepts, criteria, plus intangibles that really make one “dic-

tionary” which is accepted by all an impossibility!

Additionally on this subject there is something even more 

fascinating to me. Each school feels that what they say (or 

think) regarding certain subjects (i.e., melanocytic neopla-

sia) makes perfect sense (to them) and the other “school” is 

“wrong.” Each feels just as strongly about their own con-

cepts, criteria, etc. and cannot “believe” the other school. (In 

many instances, one school may only marginally read what 

another school writes.) Many are in between, some ideas 

from one group and also another. (I feel that before you can 

disagree with another’s concepts you must first be “clear” 

about your own and be able to state why “something is what 

it is.”) It is challenging to translate one language into another 

and thus know what the other side is “talking about” (unless 

the writing is unintelligible.)

From this imperfect work I hope you will “take what you 

want and leave the rest.”

The compendium (Part 1)

– A –
ABNORMAL MELANOCYTE: any melanocyte, particu-

larly one of a melanocytic nevus or of a melanoma, that dif-

fers cytopathologically from that of a melanocyte situated at 

the dermoepidermal junction of normal skin. By definition, a 

melanocyte positioned at that junction is normal and a mela-

nocyte of a nevus or of a melanoma is abnormal. Nuclei of 

melanocytes at the junction are small, round or oval, mono-

morphic, and monochromatic, and do not exhibit a nucleo-

lus. As a rule, nuclei of abnormal melanocytes of a nevus and 

of a melanoma are larger than those of normal melanocytes, 

sometimes, as in the case of some “classic” Spitz’s nevi and of 

some melanomas, being much larger. In nevi other than “clas-

sic” Spitz’s nevi, nuclei of abnormal melanocytes tend to be 

monomorphic and monochromatic; in “classic” Spitz’s nevi, 

they may be pleomorphic and, at times, heterochromatic. In 

melanomas, nuclei of abnormal melanocytes often are pleo-

morphic and heterochromatic. In both “classic” Spitz’s nevi 

and melanomas, nuclei may sport a prominent nucleolus, 

but only in some melanomas is that nucleolus dead center 

in a vesicular nucleus of virtually every abnormal melano-

cyte constituent. In nevi other than “classic” Spitz’s nevi, 

nuclei of abnormal melanocytes organized in aggregations 

are equidistant from one another; in “classic” Spitz’s nevi 

and in melanomas; they often are not equidistant, that being 

a consequence of variability of the size and shape of nuclei, 

but also of the amount varied of cytoplasm.

ABNORMAL MITOTIC FIGURE: a mitotic figure that is 

aberrant, such as being tripolar or tetrapolar, or of the con-

figuration of a ring, in contrast with a normal appearance 

bipolar. Abnormal mitotic figures are seen episodically in 

melanomas and, rarely, but surely, in “classic” Spitz’s nevi.

ABORTIVE: premature, prematurely, cut short.

Abortive has been defined in a variety of ways despite 

the fact that the meaning of it originally was “born prema-

turely.” In medicine in general, abortive refers to arrest in 

development, meaning that, biologically, a structure does not 

mature completely. In regard to a particular disease, the term 

also has the meaning of being “incomplete” clinically and 

histopathologically. Concerning matters morphologic, how-

ever, the word abortive, as it is applied in the language of 

dermatology and dermatopathology, has yet to be defined in 

a cogent manner.

In every instance in which the word “abortive” is employed 

for findings morphologic, the word is used wrongly. Small 

plaque parapsoriasis is a manifestation of mycosis fungoi-

des (not an abortive lymphoma), and psoriasis that spreads 

centrifugally is very much psoriasis (not abortive pustular 

psoriasis). Immature structures in sections of tissue should 

be designated immature, not abortive. An adnexal anlage is 

an immature adnexal structure, the word anlage being Ger-

man for an aggregation of cells in an embryo that represents 

the first evidence of a future structure. What is meant by 

an abortive anlage is just as opaque as what is intended by 

abortive melanosomes; melanosomes may be less than fully 

melanized, but that does not make them abortive.

ABSCESS: clinically a circumscribed collection of pus and 

histopathologically a localized collection of neutrophils.

An abscess may come into being without any cause infec-

tious, and in the skin most abscesses are not a result of infec-

tion. The most common abscesses recognizable clinically 

results from rupture of an infundibular cyst, and the most 

common circumstance in which that occurs is “cystic” acne 

vulgaris. Abscesses of noninfectious nature are encountered 

histopathologically in eruptive lesions of psoriasis, “pustu-

lar” psoriasis being a caricature of the process, they hav-

ing been given designations like Munro’s microabscess and 

spongiform pustule of Kogoj. Strictly speaking, an abscess 



Review  |  Dermatol Pract Concept 2012;3(2):4 15

consists of neutrophils and both parts and products of them; 

“necrotic tissue” and “fluid products of tissue breakdown” 

are irrelevant to the composition of an abscess. Although 

signs of inflammation, i.e., redness, may be observable 

around some abscesses, that surely is not always the case; 

for example, pustules widespread of von Zumbusch psoria-

sis sometimes develop in skin devoid of redness. At other 

times, however, these pustules are situated on erythematous 

skin. The pus of an abscess need not be flowing and may 

never flow. In contrast, suppuration refers to the formation 

or discharge of pus. An exudate is fluid that has exuded from 

tissues and it need not be pus (purulence); it may be serous 

or hemorrhagic.

A furuncle is an abscess situated around the base of a 

hair follicle, the process having begun as a suppurative 

infundibulitis that extended along the follicle to the base of 

it. The same may be said for hidradenitis suppurativa and 

its analogues, namely, acne conglobata, acne keloidalis, and 

dissecting cellulitis of the scalp (perifolliculitis abscedens 

and suffodiens). Pathologenetically, hidradenitis suppurativa 

has nothing whatever to do with eccrine or apocrine glands. 

Although the term “abscess cavity” is employed so often 

it has become cliché, it is a contradiction in terms because 

a cavity is an empty space. The same is true for “chronic 

abscess”; it is a non-sequitur because an abscess, consisting 

as it does of neutrophils, always is acute in terms of sequence 

chronologic of the inflammatory process, it being followed 

by granulomatous and fibrosing inflammation, the latter 

truly being “chronic.” Last, Pautrier’s microabscess is wrong 

on both counts: the phenomenon was described by Darier, 

not Pautrier, and the cells that make up the collection are 

lymphocytes, not neutrophils. A cluster of lymphocytes does 

not qualify as an abscess.

ACANTHO-: a prefix meaning spinous or prickle and in 

dermatology/ dermatopathology applied to spinous (prickle) 

cells of an epithelium

ACANTHOLYSIS: a process whereby epithelial cells, as a 

consequence of loss of connections (desmosomes) between 

them, separate from one another, becoming round and even-

tually dying, the process ending in formation of either a cleft 

or a blister.

Acantholysis refers to a process and, that being the case 

cannot properly be said to be a “disruption” or “dissolution.” 

Moreover, cells of the spinous, granular, and cornified layers 

may become acantholytic, for example, in focal acantholytic 

dyskeratosis as it presents itself in Darier’s disease, Grover’s 

disease, a particular kind of epidermal nevus, and a distinctive 

benign keratosis (acantholytic dyskeratotic acanthoma). Not 

only cells of the epidermis (both surface and infundibular) 

are affected, but those of cutaneous ducts and even glands, 

namely, the sebaceous, apocrine, and eccrine. When epithelial 

cells separate completely from one another, they are doomed 

to become necrotic, which, in classic pathology is a particular 

type of degenerative phenomenon typified by pyknosis, kary-

orrhexis, and karyolysis, not by hyalin, which is a generic, 

antiquated designation for any substance, ranging from fibrin 

to amyloid, that resembles glass, and, because of its utter non-

specificity, should be eschewed because it is uninstructive.

As stated earlier acantholysis pertains to a process patho-

logic that leads to formation of round epithelial cells that 

are separate distinctly from their neighbors, those cells being 

called acantholytic ones. Acantholytic cells are observed in 

different kinds of processes pathologic, among those being 

inflammatory ones, such as pemphigus vulgaris, pemphigus 

foliaceus, paraneoplastic pemphigus, infection by herpes virus 

(herpes simplex, zoster, and varicella), and Grover’s disease; 

neoplastic ones, such as squamous-cell carcinoma of the solar 

keratotic type (so-called pseudoglandular squamous-cell car-

cinoma); cystic ones, such as warty dyskeratoma; hamarto-

matous ones, such as an epidermal nevus punctuated by foci 

of acantholytic dyskeratosis, and one that escapes categoriza-

tion readily in the classification of classic pathology, namely, 

Darier’s disease. Moreover, acantholytic cells may be brought 

into being by different mechanisms, the two most common 

being immunologic, as in pemphigus vulgaris and pemphigus 

foliaceus, and secondary to the effects of products of neutro-

phils as occurs in bullous impetigo and dermatitis herpetifor-

mis. By virtue of these different mechanisms, acantholytic cells 

may appear above the basal layer, as in Hailey-Hailey disease, 

in the spinous zone mostly, as in infection by herpes virus, 

in the granular zone, as in pemphigus foliaceus, and in the 

cornified layer, as in Darier’s disease. Whenever neutrophils 

enter the epidermis in large numbers, the effects of enzymes 

released by them may induce formation of acantholytic cells 

in the spinous and granular zones, as occurs in inflammatory 

diseases as disparate from one another as pustular psoriasis 

and a pustular expression of dermatophytosis. And whenever 

neutrophils in subepidermal spaces and in subepidermal blis-

ters are extraordinarily numerous, as is expected in lesions 

developed fully of dermatitis herpetiformis and bullous lupus 

erythematosus, acantholytic keratocytes may come into being 

at the base of the epidermis.

When acantholysis occurs rapidly in an inflammatory 

disease, such as in pemphigus vulgaris, acantholytic cells 

die soon and become necrotic. When, however, acantholy-

sis develops more slowly in an inflammatory disease, such 

as is the reality in Hailey-Hailey disease, acantholytic cells 

die more slowly, permitting time for cornification to occur 

as evidenced by the presence of acantholytic cells that are 

dyskeratotic. Acantholytic cells in squamous cell carcinoma, 

warty dyskeratoma, the epidermal nevus typified by foci of 

acantholytic dyskeratosis, and in Darier’s disease all cornify 

abnormally.



16 Review  |  Dermatol Pract Concept 2012;3(2):4

The notion of “villi” appearing in any disease of the skin 

characterized by acantholysis is misguided; what are said to 

be villi are merely prominent, but normal, dermal papillae 

crowned by an epidermal basal layer above which a cleft or 

blister has formed secondary to acantholysis.

Last, it should be noted that there are no truly subcorneal 

blisters, either as a consequence of substances immunologic 

or of effects enzymatic. The blisters actually develop in the 

uppermost part of the spinous zone or in the granular zone 

and by extension upward soon result in what seems to be 

a subcorneal blister. In reality, acantholytic cells may come 

into being above the basal layer (which is viable), as well 

as in the spinous and granular layer (which also are viable), 

but they cannot come into existence immediately beneath 

the cornified layer (which is nonviable). (SEE ACANTHO-

LYTIC DYSKERATOSIS)

ACANTHOLYTIC: pertaining to acantholysis

ACANTHOLYTIC CELL: an epithelial cell that has sepa-

rated from other epithelial cells and in the process becomes 

round.

ACANTHOLYTIC DYSKERATOSIS: a condition marked 

histopathologically by changes in foci or in confluence of 

surface and/or infundibular epidermis marked by a supra-

basal cleft above which cells in the spinous and granular 

layers have cornified prematurely (dyskeratosis) and become 

separated from one another (acantholysis), in conjunction 

often with parakeratotic cells that also have become acan-

tholytic.

Acantholytic dyskeratosis is a distinctive pattern of 

changes identifiable with specificity histopathologically, it 

being a “reaction” only in the sense that all patterns histo-

pathologic observed in skin and in other organs are a reac-

tion to something; what exactly is not known with surety 

except for those patterns that result unquestionably from 

an infections agent, such as infection by papillomavirus, the 

virus of molluscum contagiosum, and herpes virus. Although 

the denominators in common for acantholytic dyskeratosis 

are a suprabasal cleft and above it the presence of cells that 

are acantholytic and dyskeratotic, concurrently, the findings 

may be met with not only in foci of surface epidermis, such 

as in Darier’s disease, Grover’s disease, and one type of epi-

dermal nevus, but also in a manner confluent dramatically 

in infundibular epidermis as occurs in the lining of a cyst 

known colloquially as warty dyskeratoma. Acantholytic dys-

keratotic cells in epidermal epithelium are not, in themselves, 

sufficient to qualify as “acantholytic dyskeratosis.” For 

example, once a blister forms, no matter whether as a papu-

lovesicle of Grover’s disease or as a bulla of Hailey-Hailey 

disease, both of those conditions being typified by the pres-

ence of acantholytic dyskeratotic cells, the findings no longer 

are considered to be mere “acantholytic dyskeratosis.” Once 

serum has entered such a space, a cleft in an epidermis that 

houses acantholytic dyskeratotic cells is transformed into a 

blister, no matter how subtle or tiny, such as in a papulo-

vesicle of Grover’s disease. When a lesion is a papulovesicle 

and no longer a papule, the term “acantholytic dyskeratosis” 

is not appropriate because the acantholytic dyskeratotic cells 

are joined by serum.

“Foci of acantholytic dyskeratosis” (focal acantholytic 

dyskeratosis) occur in surface epidermis of Darier’s disease 

and Grover’s disease, both of which are typified by lesions 

widespread. Parenthetically, in most patients with Grover’s 

disease, called originally by Grover “transient acantholytic 

dermatosis,” the condition is not evanescent, but persistent. 

Darier’s disease always consists of keratotic papules, that is, 

rough surfaced ones, and that is the case, too, for that expres-

sion of Grover’s disease in which each focus of acantholytic 

dyskeratosis is topped by a short column of parakeratosis; 

often, however, papules of Grover’s disease have a smooth 

surface because no zone of parakeratosis sits atop a focus in 

the epidermis in which acantholytic cells are accompanied 

by a tad of serum and/or a hint of spongiosis. Both the sys-

tematized and palmoplantar expressions of focal acantho-

lytic dyskeratosis are representative of a type of epidermal 

nevus. In contradistinction to focal acantholytic dyskeratosis 

is confluent acantholytic dyskeratosis, which manifests itself 

usually in so-called warty dyskeratoma, which is not a neo-

plasm (tumor) but a particular type of infundibular cyst, the 

lining of which shows acantholytic dyskeratosis in conflu-

ence. Because parakeratotic contents of the cyst are housed 

wholly within the lining enveloping of it, the papule or small 

nodule neither is seen nor felt to be keratotic clinically. Much 

more common than warty dyskeratoma, which usually pres-

ents itself as a solitary lesion, is a keratotic papule typified 

histopathologically by foci of acantholytic dyskeratosis, to 

wit, acantholytic dyskeratotic acanthoma. Although that 

keratotic papule tends to appear as a solitary lesion on a 

trunk, it may present itself rarely as several lesions.

The acantholytic dyskeratotic changes that occur in a 

solar keratosis are those of very superficial expression of 

pseudoglandular squamous-cell carcinoma and are not those 

of acantholytic dyskeratosis. The two processes are differ-

ent clinically, histopathologically, cytopathologically, bio-

logically, and conceptually, although both have in common 

acantholytic dyskeratotic cells. In focal and in confluent 

acantholytic dyskeratosis, nuclei are not crowded and atypi-

cal, and acantholytic dyskeratotic cells are present in the spi-

nous and granular zones (so-called corps rounds) and acan-

tholytic parakeratotic cells (so-called grains) are present, too. 

In contrast, nuclei of cells in “pseudoglandular” solar kerato-

sis are crowded and atypical, and acantholytic dyskeratotic 

cells are confined to the spinous zone; never are they found 



Review  |  Dermatol Pract Concept 2012;3(2):4 17

in the granular zone or in the cornified layer. The term “pseu-

doglandular” derives from the gland-like appearance, at least 

to the eye of some histopathologists of days gone by, created 

by suprabasal clefts that form consequent to acantholysis in 

aggregations of squamous-cell carcinoma; acantholytic dys-

keratotic cells with an atypical nucleus reside in those clefts. 

(SEE ACANTHOLYSIS)

ACANTHOMA: a benign proliferation characterized by a 

circumscribed increase in thickness of the epidermis conse-

quent to an increase in thickness of the spinous (prickle, mal-

pighian) zone secondary usually to an increase in number of 

cells, but episodically, to an increase in size of cells or, rarely, 

both of them together.

In practice the designation has been given to such dispa-

rate conditions as pale-cell acanthoma, in which the mor-

phologic findings are of pale-cell acanthosis, and to acan-

tholytic dyskeratotic acanthoma, in which they are of focal 

acantholytic dyskeratosis. In short, the term “acanthoma” is 

not specific and has been applied to various conditions char-

acterized by proliferation of spinous cells.

An “acanthoma” is a tumor only in the sense of a benign 

proliferation, not in the sense of a swelling; most true acan-

thomas are but slightly elevated above the surface of the 

skin, e.g., pale-cell acanthoma (Degos-Civatte) and acan-

tholytic dyskeratotic acanthoma. A so-called pilar sheath 

acanthoma is a proliferation with follicular differentiation, 

to wit, toward the isthmus, and to a much lesser extent 

with sebaceous ductal differentiation. The term acanthoma 

should not be used for tumor, unmodified, not only because 

no acanthoma is a tumor in the sense of a mass greater than 

2.0 cm in greatest diameter, but also because no acanthoma 

is malignant. In the jargon of general pathology, tumor usu-

ally denotes a malignant proliferation. Neither should the 

term acanthoma be used for a benign proliferation with fol-

licular differentiation nor for a hyperplasia.

“Acanthoma” is used for such disparate processes 

pathologic as hypertrophy (increase in size of cells) and 

hyperplasia (increase in number of cells) that comes into 

being by way of persistent mechanical trauma, as in acan-

thoma fissuratum, for a benign neoplasm such as large-cell 

acanthoma (a solar lentigo in which nuclei of keratocytes 

are larger than usual for that incipient reticulated seborrheic 

keratosis), melanoacanthoma (a pigmented seborrheic kera-

tosis peppered by melanocytes with striking dendrites), and 

clear (pale)-cell acanthoma (a benign neoplasm of epidermal 

keratocytes that spares acrosyringia), and for lesions that 

are malignant, such as keratoacanthoma which is a type 

(keratoacanthomatous) of squamous-cell carcinoma, irre-

spective of whether that neoplasm arises in skin that bears 

hair follicles or that does not subungual). Keratoacanthoma 

does not qualify as a true acanthoma, because it is a malig-

nant proliferation. (SEE TUMOR)

ACANTHOTIC: pertaining to acanthosis.

ACANTHOSIS: an increase in thickness of the epidermis 

consequent to an increase in thickness of the spinous (prickle, 

malpighian) zone secondary usually to an increase in number 

of cells (hyperplasia), but, episodically, to an increase in size 

of cells (hypertrophy) or, rarely, both of them together.

There is a difference between hyperplasia and hypertro-

phy of cells of the spinous zone; hyperplasia pertains to an 

increase in number of cells, whereas hypertrophy refers to 

increase in size of cells. Both hyperplasia and hypertrophy 

of spinous cells result in a thickened epidermis. Hyperplasia 

of spinous cells occurs, for example, in psoriasis, whereas 

hypertrophy of spinous cells appears in lichen planus. Both 

hyperplasia and hypertrophy of spinous cells are seen in 

some examples of lichen simplex chronicus.

Because the term acanthosis nearly always is employed 

conventionally as a synonym for thickening of the epider-

mis as a result of an increased number of spinous cells, it is 

incorrect to use it for proliferations, whether benign, such as 

seborrheic keratosis, or malignant, such as Bowen’s disease.

The word acanthosis also is applied aptly to hyperplasias 

like those of psoriasis, long-standing lesions of allergic con-

tact dermatitis and of nummular dermatitis, and pityriasis 

rubra pilaris. It is imprecise to refer to acanthosis as “irregu-

lar” and “regular”; neither of those modifiers ever has been 

defined in a crisp, lucid way. It is proper, however, to describe 

epidermal rete ridges as being of even or uneven length, hav-

ing a smooth or jagged outline, and being thin or thick. Each 

of those descriptors is definable in fashion comprehensible. 

In sum, although acanthosis may come into being as a conse-

quence of hypertrophy of spinous cells, when the word acan-

thosis is employed in dermatopathology, it is usually meant 

to designate hyperplasia, not hypertrophy.

ACHROMIA: state of being devoid of color. Syn. achroma-

tosis.

Achromia means a state of complete absence of color of 

the skin, but no cutaneous condition ever is devoid wholly of 

color, and that is why the term has no place in the language 

of dermatology.

The phrase so popular today among dermatologists, 

namely, “skin of color,” which is meant to apply only to the 

integument of Africans (and especially African-Americans), 

Asians (and especially Asian-Americans), and Hispanics 

(and especially Hispanic-Americans) has no basis scientific 

whatsoever; all peoples, including Caucasians, have “skin of 

color.” It is dangerous to mix political agendas suffused with 

financial incentives and the profession of medicine.

Often the word achromia is defined as absence of natural 

pigmentation, which means pigmentation by melanin, but, in 

fact, the skin is colored not only by melanin but by effects 

of the organization of corneocytes of the stratum corneum 



18 Review  |  Dermatol Pract Concept 2012;3(2):4

and of the thickness of that cornified layer (i.e., it may have 

a slightly yellow cast when corneocytes are arranged com-

pactly in a markedly thickened stratum corneum), degree of 

perfusion by blood (i.e., it may be red or livid), or by deposits 

of various kinds, i.e., of hemosiderin (which may cause the 

skin to assume a brown hue).

A reduction in pigmentation by virtue of a decrease in 

melanin in the epidermis may be designated specifically 

hypomelanosis, which is manifested clinically as hypopig-

mentation, and amelanosis, which is expressed clinically as 

depigmentation. Hypomelanosis is seen in post inflamma-

tory hypopigmentation, and amelanosis is observed in the 

depigmentation of vitiligo. Changes in color of skin may 

be indicative of a specific disease, for example, absence of 

perfusion of blood in vessels of nevus anemicus resulting in 

whiteness of that flat lesion. In short, a term that has applica-

bility clinically, such as depigmentation, is preferable to one 

that does not, such as achromia.

What is called “achromia” in the common parlance of 

dermatology is not really characterized by absence of color. 

Achromia parasitica, achromic nevus, and incontinentia pig-

menti achromians of lto, as well as lesions in yaws or oncho-

cercosis, are typified by hypopigmentation, not by depigmen-

tation; the latter being a condition that results from absence 

total of melanin from the epidermis. A distinction must be 

made in this regard, therefore, between hypopigmentation in 

which the amount of melanin from the epidermis is reduced 

considerably, as is the case in one expression morphologic 

of the patch stage of mycosis fungoides (hypopigmented 

mycosis fungoides), and absence entirely of melanin from 

the epidermis, as is the situation in lesions developed fully 

of vitiligo.

ACHROMIC: pertaining to achromia, not colored.

ACID MUCOSUBSTANCE: is a histochemical term for a 

polymer of glucose and amino groups (mucopolysaccharides, 

glycosaminoglycans) that takes a stain in an acid medium.

ACINAR: pertaining to an acinus.

ACINOUS: resembling an acinus

ACINUS: a group of berry-shaped secretory parts (alveoli) 

of a gland that are continuous with a single duct; the smallest 

lobule of a lobulated gland.

The term acinus, fundamentally, has denotations mor-

phologic, but it is defined differently in regard to different 

organs, such as the liver, pancreas, lung, and skin. The situ-

ation is even more confusing in regard to the relationship 

between acinus and alveolus. In Latin, acinus means a berry 

or a grape, whereas alveolus refers to a small sac. It is not cor-

rect, therefore, to define acinus as a small saclike dilatation; 

that is the correct definition for alveolus. In the lung, acinus 

and alveolus clearly are different from one another, alveolus 

being a tiny air containing sac, in contrast to acinus which 

is made up of numerous alveoli that enter the same terminal 

bronchiole. In regard to the pancreas and the parotid gland, 

the term acinus designates the terminal part of the gland that 

consists of secretory cells positioned around a minute hollow 

opening to a duct. In dermatopathology, the words alveolus 

and acinus pertain to structures glandular, and they often are 

used interchangeably in the sense of denoting the smallest 

part of a gland. It would be more precise, however, to define 

those words in a manner terminologic analogous to that for 

structures anatomic in the lung, employing the term alveo-

lus for the smallest portion of a gland and acinus for the 

terminal lobule of a gland that consists of a group of alveoli 

continuous with a single duct. (SEE ALVEOLUS)

The sebaceous gland is characterized by holocrine secre-

tion, meaning that individual cells of the gland rupture with 

material released from those cells becoming the secretion 

itself. It is not correct to state, however that the acini degen-

erate. The situation is just the reverse of “degeneration”; 

cells of an acinus mature and the product of that matura-

tion is sebaceous secretion. In dermatopathology, the word 

acinus is used either to designate the terminal part of a gland 

(including the eccrine and apocrine glands) or to describe the 

lobulated architecture of a gland like a sebaceous one. Terms 

like uniacinar and multiacinar derive from the second use of 

the word acinus. The eccrine gland and the apocrine gland 

are both tubular and have no lobules. Use of acinus in regard 

to an eccrine gland or an apocrine gland refers to the defini-

tion of that word as the terminal part of a gland.

ACNEIFORM: resembling clinically different expressions 

morphologic of acne vulgaris. Syn. acneform, acneiforme, 

acneforme.

The statement “resembling acne” does not convey a sense 

for how, precisely, a particular condition actually resembles 

acne. In reality, there are many manifestations morphologic 

of acne vulgaris, among them comedones, papules, papulo-

pustules, pustules, cysts, rounded masses (conglobate), drain-

ing sinuses, and scars. Each of those lesions has an appear-

ance distinctive, clinically and histopathologically. Acneiform 

lesions as they present themselves clinically, in the sense of 

resembling grossly those of acne vulgaris, may be encoun-

tered in conditions as disparate as halogenoderma, second-

ary syphilis, rosacea, tropical acne, and steroid acne, each of 

which is a process pathologic different from acne vulgaris.

Acneiform lesions as they express themselves histopatho-

logically, in the sense of resembling those of acne vulgaris, 

may be met with in conditions as unrelated as occupational 

acne (in which insoluble cutting oils, to wit, machine oils, 

induce formation of comedones), pomade acne (in which a 

perfumed ointment, particularly in a scented dressing for hair, 



Review  |  Dermatol Pract Concept 2012;3(2):4 19

causes comedones to come into being), and Favre-Racouchot 

syndrome (in which extensive exposure long standing to sun-

light, as evidenced by an extraordinary amount of solar elas-

tosis brings about comedones).

The word “acne” never should be used unmodified, any 

more than should the words “lupus” and “nevus.” Each of 

them must be employed always with a modifier, for example, 

acne vulgaris, acne keloidalis, and acne cosmetica, lupus vul-

garis, lupus pernio, and lupus profundus, and melanocytic 

nevus, nevus sebaceous, and nevus unius lateris.

Just as a reader is confounded by the definition of “acne-

iform eruptions resembling acne lesions” because the state-

ment does not make clear whether by “acne lesions” is meant 

lesions of acne vulgaris and, if that is what is intended which 

of the many kinds of lesions of acne vulgaris is meant. In 

times past rosacea was referred to by dermatologists, univer-

sally, as acne rosacea, but that practice, confusing as it was, 

is much less in evidence today. Rosacea is a disease different 

from acne vulgaris, even though both conditions have a pre-

dilection for the face, tendency to consist mostly of papules 

and pustules, and inclination to infundibulocentricity. It also 

must be emphasized that by acneiform is meant resemblance, 

clinically and/or histopathologically, to individual lesions of 

acne vulgaris, and not the disease acne vulgaris per se. Acne-

iform lesions in diseases other than acne vulgaris may be 

found at sites anatomic very different from those favored by 

lesions of acne vulgaris.

ACRAL: pertaining to the parts most distal of the body, 

referring particularly to the extremities, that is, the hands 

and feet, and especially the parts most distal of them, namely, 

fingers and toes, but also, conceptually, to other distal parts, 

such as the nose, the ears, and penis.

The word acral is used in the language of dermatology as 

a synonym for hand(s) and/or foot (feet), and especially, the 

fingers and toes, that is, the parts most distal of the limbs. 

In theory, however, acral pertains to all parts distal, such as 

the nose and the ears and even to the penis, but, in practice 

that is not the way the term is used. And that is why all the 

conditions whose name is prefixed by acro-, such as acroder-

matitis continua (Hallopeau), acrodermatitis chronica atro-

phicans, and acrosclerosis, nearly always affect hands and/or 

feet especially and sometimes, but not always, the extremi-

ties proximal to those parts most distal.

The use of the word “acral” for hands and feet in gen-

eral and for fingers and toes in particular is proper, but 

what is confusing is not the application of the term acral 

to certain sites anatomic, but the use of it to modify terms 

like “fibrokeratoma,” “nevi,” and “microlivedo,” instead of 

referring specifically to fibrokeratoma on a site acral, mela-

nocytic nevi on a site acral, and to microlivedo (whatever 

that means) on a site acral.

ACRAL PARTS OF THE BODY: the distal parts, such as 

hands, feet, and even the penis but especially the fingers and 

toes, nose, and ears.

ACRAL PARTS OF THE SKIN: refers to the distal parts, 

especially the skin of the fingers and toes, but also the nose, 

ears, and even the penis.

ACRO-: a prefix meaning the furthest point and in derma-

tology referring to the part most distal of the extremities, 

especially to hands and feet, and, more particularly, to fin-

gers and toes.

The prefix acro- usually is not employed by dermatolo-

gists as a synonym for the extremities per se, but for the 

distal part of the extremities, to wit, hands and feet, and, in 

particular, fingers and toes.

Although acro-, like acral, often pertains to the part of 

extremities most distal, as in the terms acrodermatitis con-

tinua (which is but one of many manifestations clinical of 

pustular psoriasis), acrokeratosis verruciformis (which are 

keratotic warty papules of Darier’s disease that occur on 

the dorsa of hands), and acrodermatitis chronica atrophi-

cans (a particular manifestation of Borreliosis that affects 

especially the legs and feet, and culminates in broad patches 

of atrophy), it also is applied to conditions that affect the 

face as well as the distal part of extremities, for example, 

acrogeria (which conveys an impression of severe premature 

aging), acromegaly (which gives the appearance of progres-

sive enlargement of parts affected), and acrosclerosis (which 

causes the forearms and hands, legs and feet, and face to 

look and feel tight severely) as well as to conditions charac-

terized by considerable length or height, such as acrochor-

don (which is a long, cordlike polyp or papilloma known 

colloquially as a skin tag).

ACROSPIROMA: refers to a benign proliferation composed 

of cells thought to resemble those of the distal segment of 

eccrine ducts, i.e., acrosyringia. The term encompasses con-

ditions of histopathologic characteristics very different from 

one another, among them being eccrine poroma, dermal duct 

tumor, poroid hidradenoma, and apocrine hidradenoma. 

Because the term acrospiroma is not indicative of a specific 

proliferation, it is best avoided in favor of a designation that 

actually conveys specificity.

ACROSYRINGEAL: pertaining to an acrosyringium, espe-

cially of an eccrine duct.

ACROSYRINGIUM: in general, the distal intraepithelial 

end portion of a duct of an adnexal gland (sebaceous, apo-

crine, and eccrine), but in particular and in parlance com-

mon of an eccrine duct.

Acrosyringium designates the distal intraepithelial end 

portion of a duct of an adnexal gland and, therefore, is 

not limited to the eccrine gland, the duct of which spirals 



20 Review  |  Dermatol Pract Concept 2012;3(2):4

through surface epidermis. The apocrine duct, too, has a 

distal intraepithelial part, namely, that portion of the duct 

which spirals through infundibular epidermis at about mid-

way through the course of it. The sebaceous duct also enters 

the infundibulum at the junction of it and the isthmus of a 

hair follicle. Acrosyringia of eccrine glands and of apocrine 

glands spiral in the same manner as they pass through sur-

face epidermis and infundibular epidermis respectively. The 

sebaceous duct passes through the junction of infundibulum 

and isthmus in a straight line.

For purposes practical, the term acrosyringium is used 

as a synonym for the part of the eccrine duct that spirals 

through surface epidermis, but the apocrine duct also spirals 

through epidermis, albeit the infundibular component of it. 

That being so, a distinction clear should be made between 

eccrine acrosyringia and apocrine acrosyringia. None of 

those who employ the word “acrosyringium” in articles and 

texts make that distinction. It is sufficient to refer to the duct 

of the sebaceous gland as the sebaceous duct. When authors 

write of a neoplasm being derived from an acrosyringium, 

they mean to say that it differentiates toward cells of an 

eccrine duct. It cannot be stated with surety from whence 

cells of hidroacanthoma simplex, so-called eccrine poromas, 

dermal duct tumor, and syringoma originate truly, and that 

being the case, it is best to speak and write of “differentiation 

toward” rather than “origin from.” In the case of syringoma, 

differentiation seems to be apocrine, rather than eccrine, in 

character, whereas for poromas, it can be eccrine or apocrine.

The cells of acrosyringia not only are different from 

epidermal keratocytes biologically (“separate symbionts in 

the epidermis”), but morphologically, too. The two, types of 

cells, acrosyringeal and epidermal keratocytic, can be identi-

fied for what they are by microscopy conventional especially 

in the cornified layer of normal volar skin, where corneo-

cytes of acrosyringia assume the appearance of a corkscrew 

as the duct spirals through that nonviable portion of surface 

epidermis. Moreover, acrosyringia of eccrine ducts largely 

are spared in the benign proliferations of epidermal kera-

tocytes known as pale-cell acanthoma and in the malignant 

proliferation of epidermal keratocytes (a squamous-cell car-

cinoma) called solar (actinic) keratosis.

Last, an acrosyringium does not “extend deep into the 

upper dermis”; by definition it is the intraepithelial part of 

the duct of an adnexal gland.

ACROTRICHIAL: pertaining to an acrotrichium.

ACROTRICHIUM: the distal segment of infundibular epi-

dermis that traverses surface epidermis.

The definition of acrotrichium was coined by H. Pinkus 

as the analogue follicular of the acrosyringium, by which 

terms he meant to identify the distal intraepidermal segment 

of the follicle for the former and the distal intraepidermal 

segment of the eccrine duct for the latter. Pinkus considered 

the funnel-shaped infundibulum to be the distal part of a 

follicle and he thought the acrotrichium was synonymous 

with infundibulum, it being the part that passes through the 

epidermis. In reality, however, the infundibulum is epidermis, 

it being infundibular epidermis in contrast to surface epi-

dermis, and not at all a component of the follicle (the latter 

consisting of bulb, stem, and isthmus). It should be noted 

that being the case, the concept of acrotrichium is flawed 

irreparably, not the least of those limitations being that the 

word “acrotrichium,” from two Greek elements, means the 

distal part of the hair, whereas what Pinkus intended by it 

was the distal part of the follicle which, in actuality, is the 

isthmus, not the infundibulum as he supposed, that structure 

actually being epidermis.

Although Pinkus seems to have been the only one to 

define the term acrotrichium,” it nonetheless is used widely 

by authors of textbooks of dermatology and dermatopathol-

ogy, although none of them states precisely what they mean 

by it. The confusion about the use of “acrotrichium” and 

“acrotrichial” derives from the notion erroneous that they 

are analogues of acrosyringium and acrosyringeal; they are 

not. The acrosyringium refers specifically to the intraepider-

mal part of the eccrine duct, but there is no intraepidermal 

part of a hair follicle. The follicle ends at the infundibulum, 

which is a part of the epidermis, the major component of 

which is surface epidermis. The proximal part of a follicle 

is the bulb, the distal part of the isthmus, and what lies 

between is the stem. In brief, there is no place right for the 

term “acrotrichium” in the lexicon of cutaneous histology or 

of dermatopathology.

ACTINIC: meaning caused by radiant energy, especially by 

ultraviolet light.

In dermatology and dermatopathology, the adjective 

“actinic” designates conditions in general and changes mor-

phologic in particular that are caused by exposure to radi-

ant energy and especially by ultraviolet light. The term is 

not restricted to effects chemical of those rays, but in most 

instances refers to changes pathophysiological induced by 

them. Actinic, in the original meaning of it, refers to any kind 

of ray, not only to rays of ultraviolet light. Therefore changes 

induced by x-rays, like those responsible for radiation der-

matitis, may be called properly “actinic,” but not “solar,” 

which refers specifically to rays from the sun. In short, actinic 

is a generic term that applies equally to radiation keratosis 

and to solar keratosis, whereas solar is more specific and is 

applicable, in particular, to that alteration of dermal connec-

tive tissue (solar elastosis) and to superficial squamous cell 

carcinoma of one type (solar keratosis) brought into being 

by rays of the sun.



Review  |  Dermatol Pract Concept 2012;3(2):4 21

The word “actinic” often is used synonymously with 

“solar” to designate changes morphologic that come into 

being after exposure longstanding to sunlight, i.e., solar 

(actinic) keratosis, which is a very superficial expression of 

the most common type of squamous-cell carcinoma. Whereas 

solar pertains only to exposure to sunlight, actinic desig-

nates any kind of ray that causes changes in tissue. Actinic 

(solar) keratoses and actinic (solar) elastosis nearly always 

are caused by ultraviolet light and, therefore, it is more pre-

cise to designate them solar keratosis and solar elastosis. The 

changes histopathologic in a keratosis induced by longstand-

ing exposure to x-rays are indistinguishable from those in 

a keratosis brought about by chronic exposure to sunlight. 

Solar elastosis, however, is very different morphologically 

from radiation sclerosis, the former being fibrillar and the 

latter not at all fibrillary (being termed badly “homogeni-

zation” of collagen). The type of porokeratosis named “dis-

seminated superficial actinic” is a consequence of exposure 

for many years to rays of the sun in a patient susceptible, 

presumably genetically.

ACTINIC GRANULOMA: a term that should not be used, 

because it is a misnomer as a consequence of the mispercep-

tion that the condition being referred to is something other 

than granuloma annulare on skin damaged severely by sun-

light with resultant elastophagocytosis.

ACTINO-: prefix meaning related to or caused by radiant 

energy, especially by ultraviolet light

ACTIVATED: not definable morphologically.

The word “activated” usually is not defined in dictionar-

ies or in textbooks of dermatology and dermatopathology. 

Only the verb “to activate” is defined in general dictionaries 

and in some medical dictionaries, and “activated” is men-

tioned as the past tense of that verb. “Activate” is defined 

in Collins Concise Dictionary, 2001 as “to make active or 

capable of action,” in Merriam- Webster’s Collegiate Dic-

tionary, 2001 as “to make active or more active,” in Taber’s 

Cyclopedic Medical Dictionary, 2001 as “to make active,” 

and in Dorland’s Illustrated Medical Dictionary, 2000 and 

Stedman’s Medical Dictionary, 2000 as “to render active.” 

Even were “activated” understood as “being made more 

active,” it is not clear what is meant by “active” in regard to 

findings in sections of tissue in which no action is apparent 

in the sense of anything being in motion. Lesions as they are 

observed histopathologically are static and, therefore, can-

not be described rightly as active.

Because the term “activated” is not defined in any dic-

tionary or: textbook of dermatology or dermatopathology, it 

is not clear what is meant by “activated” lesions of mycosis 

fungoides, and “activated” lymphocytes or T cells. It is clear, 

however, that none of these “activations” can be identified 

morphologically, either by inspection gross (clinically) or 

by microscopy (histopathologically). Even if the term “acti-

vated” could be defined meaningfully, for one example, as 

“being stimulated by cytokines,” changes induced by cyto-

kines may not be visualizable through a microscope con-

ventional and those changes that are visualizable may not 

be caused necessarily by effects of cytokines. Moreover, if 

lesions clinical or changes in sections of tissue are designated 

“activated,” the implication is that a stage of the same pro-

cess properly should be considered “inactivated.” But no such 

definition is to be found in any textbook of dermatology or 

dermatopathology, the reason being that no such concept 

has yet to be set forth. Therefore, there is no place in either 

dermatology or pathology, including dermatopathology, for 

the terms “active” or “activated.” Testimony to the assertion 

just made is the fate of what was called in the late 1940s by 

Arthur Allen “junctional activity” and “active” or activated 

“junctional nevus.” Those terms were as beloved by general 

pathologists and dermatologists interested in neoplasms of 

melanocytes as is the word “dysplasia” by them today. But, 

whereas “melanocytic dysplasia” (and derivatives of the con-

cept, namely “dysplastic nevus” and “dysplastic nevus syn-

drome”) has had a relatively long run, i.e., nearly 30 years 

with the promise of several decades more, “junctional activ-

ity” and “activated junctional nevus” became passé after but 

20 years, now being employed never-and with good reason. 

What Allen pictured in every one of many photomicrographs 

published was melanoma in situ.

ACTIVE: i.e., tending to act. Not definable morphologically.

In the realm of assessment morphologic in pathology, 

gross and microscopic, no action is observable in the sense 

of anything being in motion. Lesions as they are perused, 

clinically and histopathologically, are static. That being the 

case, they cannot be described rightly as being “active.”

Because no movement is discernible in lesions as they are 

viewed clinically and by conventional microscopy in sections 

of tissue, it is inaccurate to describe changes noted in them as 

being active. Of course there is activity, in vivo, in all lesions 

in the skin throughout the entire course chronologic of them, 

both in evolution and devolution; even a scar is associated 

invariably with subtle changes of remodeling, a type of activ-

ity. The rim erythematous of lesions annular, such as those of 

erythema multiforme, erythema annulare centrifugum, der-

matophytosis, lichen planus, sarcoidosis, and syphilis, often 

is referred to by clinicians as the “active border.” The proper 

designation simply is the “border,” which can be modified 

by words descriptive such as erythematous, violaceous, and 

scaly. The periphery of lesions of all inflammatory diseases of 

the skin, not only those that are arcuate, annular, and poly-

cyclic, is the zone that, in vivo, is associated with changes 

that are especially dynamic, and where histopathologically 

the infiltrate of inflammatory cells is seen to be most dense.



22 Review  |  Dermatol Pract Concept 2012;3(2):4

What Allen in the 1940s, ’50s, and ’60s called “active 

junctional nevus” was, in actuality, melanoma in situ, that 

being evident in photomicrograph after photomicrograph 

published by him. In brief, “active junction nevus” was 

wrong on all three counts: the proliferations were not active 

as judged morphologically, the melanocytes were not con-

fined to the dermoepidermal junction, and the “nevus” was 

a melanoma. It was Allen who also introduced the flawed 

notion of “junctional activity” of melanocytes. Not only was 

activity of melanocytes not discernible by microscopy con-

ventional, but Allen never defined the term itself in crisp, 

comprehensible, lucid fashion; in fact, for nearly 50 years 

Allen insisted stubbornly that melanocytes sprung directly 

from epidermal histiocytes. Both “active junctional nevus” 

and “junctional activity” are now relics historical, just as will 

be the case one day for dysplasia, including melanocytic dys-

plasia, dysplastic nevus, and the dysplastic nevus syndrome.

ACTIVE JUNCTIONAL NEVUS: is a term that should not 

be employed because it has never been defined in a com-

prehensible way. Arthur Allen, in the late 1940’s, introduced 

that phrase, but what he pictured in numerous photomicro-

graphs published as stereotypical of the condition was indu-

bitable melanoma in situ, he not acknowledging the reality 

of malignancy of it. Moreover, “active” indicates a dynamic 

that cannot be identified by microscopy; everything seen in 

sections of tissue is static.

ACCUMINATE: pointed.

In dermatology, the word “accuminate” usually is applied 

to a papule whose surface is gently, rather than sharply, 

pointed. Never is a papule characterized by a slender point; 

and that being the case the term acuminate is inaccurate as a 

description for any papules.

Accuminate in regard to a papule pertains to a lesion 

whose shape is domed to a variable degree. An examining 

finger can feel the hint of the gently pointed surface of the 

papule better than the naked eye can visualize it. Nearly 

always a papule comes to be pointed subtly because of spon-

giosis in a discrete focus of the epidermis, as is the case for 

an id reaction and for miliaria rubra. A keratotic plug is not 

pointed and, therefore does not qualify as being accuminate. 

So called condyloma acuminatum, an infection of muco-

cutaneous regions by papillomavirus, is not at all pointed, 

clinically or histopathologically, but is characterized by gen-

tle papillations. Neither is so called giant condyloma acumi-

natum of Buschke and Lowenstein pointed, the surface of 

that verrucous expression of squamous cell carcinoma usu-

ally is papillated, i.e., like nipples, rather than pointed.

ADAMANTINOID: resembling morphologically adamanti-

noma (ameloblastoma) of the bone or oral cavity; designat-

ing aggregations of cells in a neoplasm, which are columnar 

and arranged in a palisade at the periphery and separated 

from one another by prominent spaces in the center. This 

pattern is known as stellate reticulum.

The adjective adamantinoid is not defined in any diction-

ary in use commonly or in any textbook of dermatology or 

dermatopathology. The etymologic basis of it is misleading, 

the reason being that adamantinoid in histopathology does 

not pertain to resembling the hardest metal or diamond. It 

refers to adamantine; the designation for enamel of teeth, 

which indeed is very hard. Proliferations derived from cells 

of the enamel organ (ameloblasts) are called ameloblastomas 

or adamantinomas.

“Adamantinoid” is used in dermatopathology and in 

dermatology, for both a benign and malignant neoplasm of 

trichoblasts, each of which bears similarities histopathologi-

cally to adamantinoma (ameloblastoma) found in bones of 

the jaw. The benign proliferation is known as adamantinoid 

trichoblastoma and to the malignant one as adamantinoid 

trichoblastic (basal cell) carcinoma. The word adamantinoid 

as a modifier in both instances refers to the appearance his-

topathologically of abnormal trichoblasts in aggregations 

whose cells at the periphery are columnar and arranged in a 

palisaded, and whose cells in the rest of them are separated 

from another by prominent spaces that are transversed by 

elongated intercellular bridges. The pattern just described, 

known as stellate reticulum, is found stereotypically in ada-

mantinoma, but in cutaneous pathology it is encountered 

in adamantinoid trichoblastoma and adamantinoid tricho-

blastic carcinoma. The neoplastic cells in adamantinoma are 

ameloblasts, not trichoblasts.

ADAMSON’S FRINGE (A-FRINGE): marks the boundary 

between a follicular bulb and stem, and is the site at which 

cells of Huxley’s layer of the inner sheath lose their tricho-

hyalin granules and becomes compactly arranged blue-gray 

corneocytes. Above Adamson’s fringe, cornification of the 

inner sheath and of the hair itself is complete (i.e., orthokera-

totic). Nuclei are present in cells of the inner sheath and hair 

in the bulb below Adamson’s fringe, but no nuclei are detect-

able in cells in the stem above it. Dermatophytes that infect 

hair are able to descend to the level of Adamson’s fringe, but 

not below it, because those fungi are able to live only in cells 

that have cornified completely, such as those in the stratum 

corneum and nail plate.

ADENO-: prefix meaning pertaining to a gland

ADENOCARCINOMA: is a malignant proliferation of epi-

thelial cells that shows tubular (glandular and/or ductal) dif-

ferentiation or consists of glandular or ductal cells. When 

adenocarcinoma is primary in skin, the neoplastic cells 

differentiate toward sebaceous glands, apocrine glands, or 

eccrine glands (or the ducts of those glands), or tubules of 



Review  |  Dermatol Pract Concept 2012;3(2):4 23

it are lined by neoplastic cells like those glands or ducts. In 

a well-differentiated adenocarcinoma, some cells resemble 

those of normal glands, i.e., vacuolated cells of sebaceous 

glands or cells with secretion typical of apocrine glands. In a 

poorly differentiated adenocarcinoma few cells are identifi-

able with exactness as being sebaceous or apocrine, as two 

examples. Of course, any hint of “differentiation” can be 

helpful in the diagnosis. Some adenocarcinomas in skin are 

not primary there; they are metastases.

ADENOID: having the appearance of a gland or duct of a 

gland.

In dermatopathology, adenoid pertains to looking like a 

cutaneous gland or the duct of a gland as evidenced usu-

ally by formation of tubules, those structures being apocrine 

glands or ducts of them, and eccrine glands and the ducts of 

them. The term “adenoid” is not applied to an appearance 

like that of the third gland in the skin, to wit, the sebaceous 

gland, which consists of lobules rather than of tubules, or to 

the duct of it which, although it is tubular, cornifies, and, as 

a consequence, has an appearance entirely different histo-

logically from that of the duct of an apocrine or an eccrine 

gland. At times, cells with glandular differentiation can be 

identified in a proliferation even in the absence of a single 

tubular structure, such as the clear cells of apocrine hidrad-

enoma, known also as solid-cystic hidradenoma, clear-cell 

hidradenoma, and pale-cell hidradenoma. Neoplastic epithe-

lial cells in an apocrine mixed tumor can be recognized for 

what they are by their shapes polygonal and plasmacytoid. 

In cutaneous pathology, unlike pathology in general, the 

word adenoid never is applicable to lymphoid tissue.

The designation “adenoid” for a type of seborrheic kera-

tosis is inaccurate because the cords of pigmented epider-

mal cells in no way resemble glands themselves or ducts of 

glands, the synonym for the adenoid type of seborrheic kera-

tosis being “reticulated,” which means netlike, as truly is the 

situation in time for that benign keratosis. The acantholytic 

type of solar (actinic) keratosis is but a stage in the evolu-

tion of what later is termed, conventionally, pseudoglandular 

squamous-cell carcinoma, the gland like structures coming 

into being as a consequence of the formation of acantho-

lytic, dyskeratotic spinous cells above suprabasal spaces of 

aggregations that make up the malignant proliferation. In 

actuality, the suprabasal clefts bear no resemblance truly 

to any gland. The term adenoid cystic carcinoma is correct 

only partly, that particular expression of apocrine carcinoma 

being adenoid in the sense that those aggregations are punc-

tuated by round spaces that house mucin, thereby conveying 

the impression vaguely of gland like structures in cribriform 

pattern. Those spaces, however, are not truly glandular and, 

moreover, are small, which disqualifies them as being cystic.

ADENOID CYSTIC: refers to a distinctive sieve like pattern 

in an epithelial neoplasm in which discrete aggregations of 

cells house spaces that are relatively equidistant from one 

another, are relatively uniform in size and shape, and contain 

mucin. The term is derived from the appearance of a type of 

carcinoma of salivary glands, but it has come to designate 

other malignant proliferations with a similar pattern in other 

sites, such as types of apocrine carcinoma and trichoblastic 

(basal-cell carcinoma).

The designations adenoid cystic carcinoma, adenocystic 

carcinoma, adenocystic basal cell carcinoma, and adenoid 

basal cell carcinoma are confusing. In brief, adenoid cystic 

carcinoma is a specific type of carcinoma that may develop 

in skin, where it shows signs of apocrine differentiation, in 

salivary glands, and in the breast, an organ whose mammary 

glands exhibit apocrine secretion. Adenocystic carcinoma is 

also a specific neoplasm that, in the skin, is better known as 

mucinous carcinoma, and in the breast, as colloid carcinoma. 

Like adenoid cystic carcinoma, adenocystic carcinoma some-

times shows evidence of apocrine secretion. In contrast, the 

so called adenocystic and adenoid types of trichoblastic 

(basal cell carcinoma), although devoid of signs of follicular 

differentiation (i.e., germs and papillae, bulbs and papillae, 

trichohyalin granules, and blue-grey corneocytes arranged 

compactly), are composed of follicular germinative cells and 

are all nodular trichoblastic (basal cell carcinomas). They 

do not show evidence of apocrine differentiation. It would 

be preferable to call these three neoplasms adenoid cystic 

carcinoma, mucinous carcinoma, and trichoblastic (basal 

cell carcinoma), because their morphologic variations are so 

numerous and, with rare exceptions those variations do not 

influence biologic behavior. Adenoid cystic carcinoma and 

mucinous carcinoma may arise in the skin and in the breast 

where their morphologic features are maintained.

ADENOMA: a benign proliferation made up of glandular or 

ductal cells that often assume the forms of tubules, an indica-

tion of glandular or ductal differentiation.

An adenoma is a tumor only in the sense that it is a pro-

liferation; it may present itself clinically as a papule, nodule, 

tumor, or plaque. The malignant counterpart of adenoma is 

adenocarcinoma. An adenoma consists of cells of glandu-

lar or ductal character, and although it usually shows signs 

of glandular or ductal differentiation, it may not necessar-

ily do that, i.e., some apocrine mixed tumors are entirely 

solid, being composed wholly of polygonal and plasma-

cytoid myoepithelial cells and most examples of clear-cell 

syringoma are devoid entirely of tubules, as are numerous 

examples of the poromas.

Origin is irrelevant to characterization of adenoma; it 

matters not from whence an adenoma derives (i.e., there is 

no clue to the origin of adenomas known as in cylindroma, 

spiradenoma, apocrine hidradenoma, and poroid hidrad-



24 Review  |  Dermatol Pract Concept 2012;3(2):4

enoma, no connection being apparent to preexisting normal 

glandular or ductal epithelium), only that the cells that make 

it up are glandular or ductal in nature and they are given to 

glandular or ductal differentiation as evidenced by forma-

tion of structures that resemble glands or ducts.

What is termed, conventionally, sebaceous adenoma, 

really is a superficial sebaceous carcinoma (this is a matter 

of debate) analogous to superficial basal cell carcinoma and 

to solar keratosis, the latter being a superficial squamous-cell 

carcinoma of one type. So-called cystic sebaceous adenoma 

is a histopathologic variant of sebaceous carcinoma and, 

nearly always, indicates that the patient who bears it has 

Muir-Torre syndrome. Adenoma sebaceum is a misnomer on 

both counts, namely, it is not a benign neoplasm of glandular 

or ductal cells and it is unrelated to sebaceous epithelium. 

In actuality, it is a type of follicular hamartoma joined by 

angiofibromatous elements and often by an increase in num-

ber of melanocytes at the dermo-epidermal junction. The 

findings morphologically of adenoma sebaceum are identical 

to those of fibrous papule of the face. Trichoadenoma is also 

incorrectly used. It is basically infundibular and is therefore, 

epidermal not glandular. Apocrine papillary cystoadenoma 

and tubular adenoma are correct uses.

ADENOMATOID: resembling an adenoma.

ADENOMATOUS: relating to an adenoma.

ADIPO-: prefix meaning relating to fat.

ADIPOBLASTS: known also as lipoblasts, are mesenchyme-

derived presumptive fat cells that are present normally only 

in embryonal and fetal fat.

ADIPOCYTE: a non-epithelial cell that manufactures lipid 

and, when mature, sports cytoplasm consisting entirely of a 

large vacuole of fat. syn. lipocyte, adipose cell.

An adipocyte is not “a fat cell,” the cell is not fat, it is 

filled with fat! Moreover, the definition “fat cell” does not 

distinguish an adipocyte from a lipophage, which is a mac-

rophage that houses fat or an adipocyte from a mature sebo-

cyte, which is an epithelial cell that produces fat. An adi-

pocyte makes fat which then is stored in its cytoplasm. An 

immature adipocyte does not display a large vacuole of fat 

within its cytoplasm; it may exhibit only a tiny vacuole, if 

one at all.

Adipocytes in the subcutaneous fat, each one of which is 

encircled by a capillary, are arranged in lobules intersected 

by fibrous septa that by virtue of the intersections create an 

appearance of a fenestrated pattern. An adipocyte has a cell 

membrane, not a cell wall. Mature fat is designated white 

because of the cast of it grossly, whereas immature fat in 

an embryo is termed brown because of its hue macroscopi-

cally. In contrast to white fat, brown fat contains many small 

vacuoles in its cytoplasm, thereby earning its nickname mul-

berry cell.

ADIPOSE: pertaining to or consisting of adipose tissue.

ADIPOSE TISSUE: connective tissue made up of adipocytes 

and arranged usually in lobules separated from one another 

by fibrous septa.

Adipose tissue is not simply fat, like triglycerides and 

cholesterol, and it is not just fatty tissue because sebaceous 

lobules also could be said to be fatty tissue. Adipose tissue is 

that kind of connective tissue which consists mainly of adi-

pocytes, i.e., nonepithelial cells that manufacture lipid and, 

when mature, consists almost entirely of a large vacuole of 

fat, the nucleus being so inconspicuous at the very periphery 

of the cell that it often is bypassed by the knife of a micro-

tome. A definition of adipocytes being a cell distended by 

droplets of fat is not precise because that definition applies 

equally to mature sebocytes and to lipophages. Adipose tis-

sue not only consists of adipocytes, but of those cells arrayed 

characteristically in lobules that come into being by virtue of 

struts in the form of fibrous septa that house blood vessels 

and nerves.

The subcutaneous fat consists of adipose tissue arranged 

in lobules that are created by intersections of fibrous septa. 

There are two kinds of adipose tissue in the human body, 

namely, brown and white, the latter being the constituent of 

the subcutaneous fat. Some neoplasms, such as lipomas and 

variations on the theme of them, such as angiolipomas and 

fibrolipomas, are made up of adipocytes arranged in lob-

ules, but that does not qualify as adipose tissue because the 

arrangement of cells in conjunction with fibrous septa does 

not approximate that which is characteristic of normal adi-

pose tissue, such as is met with in the panniculus adiposus.

Distinction between mature and immature adipose tis-

sue turns on the presence or absence of immature adipocytes 

(adipoblasts). Subcutaneous tissue does not always consist of 

mature adipose tissue, e.g., that in an embryo.

ADNEXA: sing. adnexus; In general, structures that are 

adjacent or subordinate to more major anatomic parts and 

in dermatology in particular, structures accessory to the two 

major components of the skin, namely, the epidermis and the 

dermis, including both ones that are epithelial (the folliculo-

sebaceous-apocrine unit, the eccrine unit, and the nail unit) 

and ones that are nonepithelial (the nerves, smooth muscles, 

and blood and lymphatic vessels.)

In general the term “adnexa” refers to parts that are 

in continuity with or in close proximity to a more major 

organ, such as the ovaries and fallopian tubes in regard to 

the uterus. In the skin, however, the word “adnexa” does not 

designate adjunctive parts, but rather authentic components 

of it, namely, those that are epithelial, such as the folliculo-



Review  |  Dermatol Pract Concept 2012;3(2):4 25

sebaceous-apocrine and eccrine units and the nail unit, and 

those that are nonepithelial, like nerves, smooth muscles, 

and vessels. In contradistinction to the adnexal (accessory) 

epithelial and non-epithelial components of the skin, the 

appendages, that is hair shaft and nail plate, are structures 

produced by epithelial components of the skin, to wit, cells 

in the matrix of a hair follicle and cells in the matrix of a 

nail unit, respectively. In sum, adnexa and appendages of the 

skin are not synonyms; appendages represent the products 

generative of adnexa.

The term “adnexa” is employed by most authors only for 

certain epithelial structures in the skin, namely, folliculoseba-

ceous-apocrine and eccrine ones, but it is not used by them 

for the nail unit. Moreover, the term “adnexa” refers rightly 

not only to epithelial structures, but to nonepithelial ones like 

nerves, smooth muscles, and vessels. A part of an adnexal 

epithelial structure may be rooted in the subcutaneous fat, 

not simply in the dermis. For example, glands of apocrine and 

eccrine units and the bulb of follicles situated on the scalp 

are lodged in the subcutaneous fat. The same statement can 

be made about some nonepithelial adnexal structures, such 

as blood vessels and nerves in the subcutaneous fat that are 

in continuity with those same structures in the dermis. Philo-

sophically and practically, nonepithelial structures in contigu-

ity with epithelial structures of adnexa, for example, a follicu-

lar papilla and a perifollicular sheath juxtaposed to a follicle, 

are, in actuality, adnexal structures, too.

ADNEXAL: pertaining or relating to adnexa

ADNEXOCENTRIC: describes the orientation of cells par-

ticularly melanocytes of a congenital nevus around epithe-

lial and nonepithelial structures of adnexa. These are some 

similar uses with “angiocentric.” However this arrangement 

is an expected finding in this type of nevus and therefore is 

redundant (as is angiocentric). (SEE ANGIOCENTRIC)

ADVENTITIA: the outermost connective tissue of an organ, 

vessel, or structure, but, not applied usually to organs cov-

ered by a serosa.

Often “adventitia” is said to be a synonym for “tunica 

externa” of the arteries and venules, which consists of con-

nective tissue. More correctly, the term adventitia is defined 

as the outermost layer of any organ, except for those covered 

by serosa.

The term “adventitia” is employed rarely in regard to 

the skin and then usually in reference to the combination of 

papillary dermis and periadnexal dermis, those two parts of 

similar composition being termed the “adventitial dermis.” 

The word adventitial is applied, too, to the outermost part 

of arteries and veins, the adventitia of arteries being made 

up of collagen and elastic fibers, and containing tiny nerves 

and capillaries, the “vasa vasorum.” Sometimes, elastic fibers 

form an “external elastic membrane” in vessels muscular, but 

it is always less prominent than the internal elastic mem-

brane, which typically is present in arteries and not in veins.

ADVENTITIAL: pertaining to adventitia and in the skin to 

the combination of papillary dermis and periadnexal dermis, 

the two, together being designated the adventitial dermis.

AGGREGATION: collection of discrete units of the same 

kind of cells or fibers.

An aggregation is not a clumped mass of material, but a 

collection or a cluster of units of the same kind of cells or of 

fibers that remain discrete and separate from one another. 

The word derives from the Latin grex meaning collection or 

herd. In the realm of histopathology, aggregations may con-

sist of cells or of fibers. In the sphere of clinical dermatology, 

when lesions of the same kind are aggregated, the phenom-

enon is referred to as agminated.

Aggregation and aggregate are used synonymously to 

designate collections of structures of the same kind, such as 

epithelioid cells, smooth muscle cells, blood or lymph vessels, 

or filaments of amyloid.

AGGREGATED: characterized by aggregation.

AGMINATED: lesions in a cluster, each of which is discrete 

and of a single kind.

The term agminated refers to lesions that are clustered, 

aggregated, or grouped, but it implies, too, that individual 

lesions in the group are discrete and of the same kind, like 

sheep in a herd. An agminated Spitz nevus would be an 

example of this.

The word aggregated, which sometimes is employed as 

a synonym for agminated, conveys the sense that the lesions 

are similar to one another, but it does not communicate that 

those lesions are discrete, i.e., not given to confluence, as is 

the case for ones that are agminated.

Lesions in the skin may be grouped in a fashion other 

than agminated, among those being herpetiform, zosteri-

form, corymbiform, segmental, linear, and annular. Agmi-

nated is the proper designation for discrete lesions of a single 

kind that are grouped together at a particular site, but that 

are not arranged in special distribution, such as along a der-

matome, in a line, or in a ring. For that reason, lesions that 

are segmental and confluent are not truly agminated. More-

over, the designation “agminate folliculitis” is incorrect; the 

pustules, by themselves, could be considered correctly to be 

agminated because they are similar to one another and are 

present in a cluster, but the fact that they are present within 

“erythematous plaques” excludes them from being desig-

nated rightly agminated.

ALOPECIA: loss of hair, either physiologically or pathologi-

cally, or absence of hair from birth on.

Alopecia should refer not only to absence of hair, but 

also to loss of hair, in fashion either diffuse or localized. The 



26 Review  |  Dermatol Pract Concept 2012;3(2):4

term alopecia conveys nothing about either the extent of loss 

of hair in terms of geographic range or amount of actual loss 

at a particular site, nor does the word communicate any-

thing about the anatomic site or sites at which the loss of 

hair occurs. Loss of hair can appear only at sites where hair 

is present normally, i.e., the scalp as opposed to palms and 

soles, no hair being present normally at those latter sites. 

Neither is the cause of a particular loss of hair transmitted 

by the term alopecia, which in the vast majority of instances 

is not a result of an inflammatory process but of one wholly 

physiologic, namely, the effect of androgens on common 

(androgenetic) baldness. In short, alopecia is a general des-

ignation for all kinds of hair loss and for absence of hair 

irrespective of cause, site, or kind of follicles (terminal or vel-

lus) affected. It may be consequent to destruction of follicles 

themselves, but also to inability of terminal follicles to main-

tain their structure, they, in the course of time, becoming vel-

lus (as is the situation in androgenetic [common] baldness) 

or to severing of hair shafts of follicles whose viable epithe-

lium remains intact (as is the situation in trichotillomania).

The term alopecia is generic for loss or absence of hair 

and conveys nothing about the specific kind of hair loss. No 

pattern typical for alopecia exists, the range being extraor-

dinary, from a macule of alopecia areata to alopecia uni-

versalis (these two being different extents of a single patho-

logic process mediated by lymphocytes) and from a subtle 

retraction of the hair line anteriorly to near total baldness 

in androgenetic alopecia (those two being different extents 

of a single pathologic process devoid of infiltrates of inflam-

matory cells and mediated by the effects of hormones). Loss 

of hair can be caused also by factors as diverse as congenital 

absence of follicles (aplasia cutis), follicles rendered defec-

tive because of the effects of a drug administered systemi-

cally (i.e., cyclosporin), an inflammatory process that sends 

follicles in anagen into telogen (i.e., “moth-eaten” alopecia 

of secondary syphilis), destruction of hair shafts by an infec-

tious agent (i.e., a dermatophyte), and a congenital abnor-

mality of hair shafts (i.e., monilethrix). It is not correct that 

alopecias are inflammatory in most instances; “common 

baldness” is so designated because it is the most common 

type of alopecia far and away, being entirely physiologic and 

unassociated with an infiltrate of inflammatory cells. It is 

wrong equally to use aberrant hair growth as a synonym 

for alopecia, because hypertrichosis as it occurs in hirsut-

ism also could be deemed properly a kind of abnormal hair 

growth. Congenital alopecia can result from absence of 

follicles or lack of growth of hair and, therefore, alopecia 

cannot be defined only as loss of hair, because it may be a 

consequence of absence of hair from birth.

ALOPECIC: pertaining to total loss of hair physiologically 

or pathologically, or to have an absence of hair from birth.

ALVEOLUS: in dermatopathology, the words alveolus and 

acinus pertain to structures glandular, and they often are 

used interchangeably in the sense of denoting the smallest 

part of a gland. It would be more precise, however, to define 

those words in a manner terminologic analogous to that for 

structures anatomic in the lung, employing the term alveo-

lus for the smallest portion of a gland and acinus for the 

terminal lobule of a gland that consists of a group of alveoli 

continuous with a single duct.

AMELANOTIC: pertaining to absence of melanin.

The adjective amelanotic designates the complete 

absence of melanin in tissue in general and in melanocytes 

in particular. Absence of melanin does not mean that a tissue 

is necessarily nonpigmented because other pigments may be 

deposited in the skin, among them, hemosiderin, hematoi-

din, and exogenous pigments, such as those of tattoos. The 

adjective amelanotic is not restricted to findings in the skin 

because an amelanotic metastasis of melanoma may be pres-

ent in any organ.

Amelanotic is used most often to designate a type of mel-

anoma, i.e., one that is red or skin-colored clinically devoid 

of melanin histopathologically. When studied by electron 

microscopy, the neoplastic melanocytes in an amelanotic 

melanoma house melanosomes, some of which may be mela-

nized partially. A condition termed amelanosis is typified not 

only by absence of melanin from melanocytes, but from ker-

atocytes, too, consequent to a defect determined genetically 

in the metabolism of melanin. (SEE ACHROMIA)

AMIANTACEA: like asbestos. Syn. amiantaceous.

In general, amiantaceous or amiantacea means like asbes-

tos an in particular in dermatology those adjectives designate 

a lesion that clinically is covered by a scale so thick and hard 

that it resembles asbestos.

Tinea (pityriasis) amiantacea is not a disease per se, but a 

description of scales so thick and hard that they are reminis-

cent of the structure of asbestos. Some authors employ the 

term tinea amiantacea for a manifestation of psoriasis on the 

scalp, others for seborrheic dermatitis complicated by infec-

tion with bacteria, still others for an expression on the scalp 

of nonbullous congenital ichthyosiform erythroderma, and 

some as a disease unto itself. In actuality, amiantaceous as 

a descriptive term is analogous to ostraceous, furfuraceous, 

and rupial. These latter terms and amiantaceous are not used 

often in dermatology anymore.

AMORPHOUS: having no distinctive shape; without char-

acteristic shape.

The adjective amorphous describes something that has 

no readily recognizable characteristic shape However, all 

structures in the skin (and in every other organ) have an 

identifiable shape; none are amorphous. The word “amor-



Review  |  Dermatol Pract Concept 2012;3(2):4 27

phous,” therefore, has no place in description of gross or 

microscopic attributes of any organ.

In every instance in dermatology and dermatopathology 

in which the word “amorphous” is employed, the structure 

in point is not shapeless; it has a definite shape. For exam-

ple, amyloid in the papillary dermis in macular and papular 

(lichenoid) expressions of amyloidosis is globular, as is the 

secretion “pinched off’” by cells of an apocrine gland. Mucin 

is finely granular, crystals of gout are spicular, and colloid is 

homogeneous. Never, therefore, can the term “amorphous” 

be applied properly to any component of the skin.

AMPHOPHILIC: stained with both acid and basic stains, 

(i.e., with hematoxylin and eosin), as is expressed in a color 

that combines pink and blue. Syn. amphophil, amphophile, 

amphophilous.

Amphophilic refers to capability to stain with both acid 

and basic dyes as is the case for the abundant cytoplasm of 

abnormal melanocytes of polygonal shape in “classic” Spitz’s 

nevi that with hematoxylin and eosin are colored pink and 

blue together.

The word “amphophilic” is used correctly in current text 

books of dermatology and dermatopathology.

AMYLOID: homogeneous, amphophilic, often globular 

material (consisting of glycoproteins) that may be deposited 

in a variety of tissues, among them being those of the skin 

and subcutaneous fat, when stained by crystal violet appears 

red, and when examined through an electron microscope is 

seen to be composed of straight fibrils 7.5-10mm in diameter.

Amyloid, in the original meaning of the word, designates 

substances that when stained with iodine respond in a man-

ner similar to that of starch. In the skin, however, amyloid is 

not a complex of mucopolysaccharides, but consists of vari-

ous substances that have in common a similar appearance 

in sections of tissue stained with hematoxylin and eosin and 

with crystal violet (Congo red is ineffective for demonstrat-

ing amyloid with repeatability in the skin), as well as a con-

sistent appearance in sections of tissue examined by electron 

microscopy. Biochemically, the various substances known as 

amyloid share the basic structure of glycoproteins, but they 

are very different from one another in origin and in other 

details. In the skin, amyloid derived from necrotic epidermal 

keratocytes as a consequence of animated scratching is pres-

ent in the papillary dermis (at first as macular amyloidosis 

and, if that condition is then rubbed persistently for long, 

as papular [lichenoid] amyloidosis), whereas amyloid that 

comes into being from a systemic disease, e.g., a dyscrasia of 

plasma cells, may be deposited in the wall of vessels, leading 

thereby to leakage of erythrocytes and even to hemorrhage. 

Under no circumstance should amyloid be characterized as 

being “hyaline in appearance” because “hyaline” is a term 

generic that lacks specificity.

In short, the definition of amyloid as a substance morpho-

logic does not turn at all on the origin of it or on the biochem-

ical character of it, but on the appearance of it as assessed by 

conventional microscopy and electron microscopy. The term 

amyloid lacks specificity because there are so many different 

kinds of amyloid. Where as amyloid derived from necrotic 

epidermal keratocytes may contain melanin and be stained by 

anticytokeratin antibody, amyloid that comes from immuno-

globulins secreted by plasma cells lacks those characteristics. 

Not only does some material designated amyloid come from 

sources other than immunocytes, but, as a rule, amyloid in 

the skin is made up mostly of necrotic keratocytes. Different 

kinds of amyloid deserve to be given different appellations. 

Were that practice employed, the term “amyloid,” unmodi-

fied, would become as passé as lentigo, unmodified, nevus, 

unmodified, and parapsoriasis, unmodified.

ANAGEN: that part of a follicular cycle during which a hair 

grows because the bulb is formed fully and matrical cells in 

the center of it mature to become the hair shaft.

Anagen is not the “growing phase of a hair follicle” and 

not the “growth stage of hair development,” but that part of 

the follicular cycle during which a hair grows. It is not the 

follicle that is growing, but the hair shaft that is growing 

as a consequence of maturation of matrical cells, just as is 

the case also for the inner sheath and the outer sheath, both 

of which represent maturation of matrical cells situated off 

center in the bulb. Moreover, it is not necessary to designate 

that part of the follicular cycle as “active” because growth of 

hair is never passive. Last, it is the follicle that cycles, not the 

hair, the stages in that cycle being known as anagen (during 

which the bulb of a fully formed follicle produces a growing 

hair), catagen (during which the bulb and stem of a follicle 

involutes), and telogen (during which only the isthmus of the 

follicle and, continuous with it, a tiny remnant of the inferior 

segment, i.e., bulb and stem remain, “resting” prior to the 

onset of anagen anew).

Vellus hair follicles proceed through the same cycle as do 

terminal follicles, but the former are situated more superfi-

cially, always rooted in the upper part of the reticular dermis, 

in contrast to terminal follicles that are based in the lower 

part of the reticular dermis and, sometimes, in the subcutane-

ous fat, such as is invariable on a normal scalp with pelage 

prominent. Every time reference is made to “hair cycle,” it is 

“follicular cycle” that is meant; the follicle cycles, not the hair.

ANALYSIS: denotes separation of elements into component 

parts, such as the act of assessing the components of histo-

pathology patterns in order to come to a specific diagnosis, 

as of an inflammatory or neoplastic skin disease. Pattern 

analysis is part of the method by which the diagnoses of 

inflammatory and proliferative skin diseases are made. Using 



28 Review  |  Dermatol Pract Concept 2012;3(2):4

pattern analysis, silhouette, algorithms, and other tools the 

diagnoses of such diseases can be made in an orderly way.

ANAPLASIA: a characteristic particular of a neoplasm, usu-

ally a malignant one, in which all of the cells constituent 

are immature, that is, nuclei of them are crowded, pleomor-

phic, and heterochromatic, and cytoplasm is scant, thereby 

precluding identification with specificity either of the cells 

themselves or of the proliferation itself; immaturity of cells 

of a neoplasm.

Reversion pertains to characteristics biologic, not to attri-

butes morphologic; one cannot observe reversion through a 

microscope. For that reason, anaplasia, if it is to be employed 

at all, should refer to findings morphologic and not to func-

tion. Although the changes seen in anaplasia doubtlessly 

reflect abnormal growth of cells and possibly even reversion 

in growth of them, growth in any form is irrelevant to defi-

nition of the term. “Primitive” implies primary or original, 

and the abnormal cells of anaplasia surely cannot be judged 

to qualify as that. Individual cells of a proliferation may be 

described as immature, partially mature, or mature, but not 

as undifferentiated, poorly differentiated, or well differenti-

ated; only numerous cells in proximity to one another can 

differentiate, that is, form structures that resemble those in 

normal tissues or organs of an embryo, a fetus, or an indi-

vidual postnatal. If by dedifferentiation is meant “regres-

sion of a specialized cell or a tissue to simpler unspecialized 

form (Stedman’s 2001), then despite the inadequacies of 

that definition, dedifferentiation is a synonym for anaplasia 

and should be defined, as we have proposed, in the same 

way, namely, morphologically, not biologically. Phrases like 

“loss of orientation [of cells] to one another and to their 

axial framework and blood vessels” and “nuclear contour 

angulation” are uninformative and, therefore, are unhelpful 

in defining “anaplasia.”

The problems inherent in the definition by others of the 

term “anaplasia” become manifested in usage of the word. 

In short, there is no unanimity in regard to how anaplasia 

should be employed. Some authors utilize it to describe 

abnormalities cytopathologic that conventionally are desig-

nated “nuclear atypia,” others for lack of features histopath-

ologic they deem to be specific, and still others as a synonym 

for dysplasia, a term that is often invoked but has yet to 

be defined in a comprehensible, lucid, repeatable manner. In 

brief, failure to define anaplasia in a manner meaningful ren-

ders the word useless in the parlance of pathology in general 

and of dermatopathology in particular.

ANASTOMOSE: to connect or join structures by a union of 

parts in a fashion intercommunicating.

The verb to anastomose does not mean to connect struc-

tures that formerly were separated, but rather to link two 

structures, usually ones of the same kind. Those structures 

not only can be vessels, but ones tubular such as those in apo-

crine cribriform carcinoma and those solid such as abnormal 

trichoblasts in cords and columns of fibroepitheliomatous 

trichoblastic (basal-cell) carcinoma. Those structures linked 

surely need not have been separated previously.

The verb “anastomose” is used rarely in dermatology 

and dermatopathology, whereas the word anastomosing, 

which is derived from it, is employed commonly as an adjec-

tive for a pattern, usually of a neoplasm, in which numerous 

communications are established among structures of similar 

composition. The term is not restricted to angiomatous or 

vascular structures as, for example, in sinusoidal hemangi-

oma. “Anastomosing” also is employed as a synonym for a 

pattern of epithelium in which cords and columns are linked 

in a manner fenestrated.

ANASTOMOSED: characterized by anastomosis.

ANASTOMOSING: describes a pattern in which numerous 

communications are established among structures of similar 

composition, it being created by structures tubular housed 

in proliferations of epithelial cells that exhibit adnexal dif-

ferentiation, such as apocrine mixed tumors and apocrine 

fibroadenomas. Fibroepithelial trichoblastic (basal cell) 

carcinoma (Pinkus) also is marked by anastomosis striking 

of cords and columns of neoplastic cells, the arrangement 

of elements epithelial and nonepithelial in that condition 

resembling windows separated by panes, i.e., fenestrated.

ANASTOMOSIS: the union of parts in a manner intercom-

municating.

The word “connection” is not quite right to character-

ize anastomosis because it does not convey the sense that 

the two structures joined actually communicate with each 

other. A connection exists, too, between structures linked 

but without any communication of them. The word “union” 

describes better the continuity between structures in an 

anastomosis.

In dermatology, the word anastomosis is employed 

nearly exclusively to refer to communication between blood 

vessels. In general, the term also designates communications 

between structures tubular, such as between the gastrointes-

tinal and the urogenital tracts, consequent to a union pro-

duced artifactually. In principal, the term anastomosis could 

be used for communication between solid structures of the 

same kind, i.e., trabeculae of neuroendocrine carcinoma, as 

well as between tubular structures of the same kind.

ANATOMY: is a science that pertains to the structure of the 

body of an animal (or plant) and to the relationship of the 

parts of the body to one another. It is predicated mostly on 

what is learned from dissection of a body. Gross (macro-

scopic) anatomy deals with structures that can be identified 

by a naked eye. In contrast, histologic (microscopic) anat-



Review  |  Dermatol Pract Concept 2012;3(2):4 29

omy deals with structures so minute that they can be seen 

only through a microscope.

ANEMICUS: anemic, bloodless.

In dermatology, the English word anemia hardly ever is 

encountered, where as the Latin word anemicus is used to 

designate pallor of lesions clinical, it’s pertaining solely and 

specifically to reduction or absence of perfusion with blood 

of a tissue in a locus discrete.

The adjective anemicus, which is synonymous with ane-

mic, appears in the term “nevus anemicus,” a site of skin 

localized that lack the usual perfusion of blood. When ery-

thema is induced in the skin adjacent to nevus anemicus, as is 

done conventionally by applying ice to the region, the lesion 

of nevus anemicus itself remains white, in contrast stark 

to the redness of the skin around it. No relationship exists 

between the appearance anemic of those nevi and anemia 

systemically. A reference to “anemic infarcts” is incorrect 

because the infarct is not anemic; the infarct causes pallor 

of tissue because the lumen of vessels that supply the site 

is obstructed. Moreover, in medicine in general, the word 

anemic is used principally to convey a relationship direct 

to anemia. In that sense, an anemic infarction would be an 

infarct caused by anemia, which certainly is not the case. In 

dermatology, anemic should be used only as a designation of 

lesions that lack perfusion with normal blood, the example 

consummate of that being nevus anemicus.

ANETODERMA: a kind of atrophy of the skin character-

ized clinically by a protrusion (colloquially referred to as an 

outpouching) in the form of a papule or a nodule that is so 

compressible it can be herniated readily and histopathologi-

cally by loss of elastic fibers especially, but also of collagen in 

the reticular dermis, usually in the upper half of it.

Anetoderma is a term generic for one type of cutaneous 

atrophy, namely, that characterized by slackness in the form 

of a pouch, an appearance that result from loss of elastic 

fibers especially, but also of collagen, in the upper half of the 

reticular dermis.

Atrophy results from loss of substance, and in the skin 

there are two basic types of it, to wit, that which involves 

loss of dermal papillae (with subsequent loss of epidermal 

rete ridges) and the other that involves loss of a rather cir-

cumscribed zone of reticular dermis. Almost always, those 

two expressions of atrophy are secondary to the effects of 

products of inflammatory cells, although the first type also 

may be consequent to the effects of neoplastic lymphocytes 

in mycosis fungoides (i.e., poikiloderma vasculare atrophi-

cans). Loss of dermal papillae leads to atrophy clinical typi-

fied by skin that displays a shiny surface, loss of normal skin 

markings, and capability to wrinkle easily when it is com-

pressed between the thumb and the forefinger. Sometimes 

wrinkling is apparent without intervention by the fingers 

of an examiner. When there also are changes associated of 

hyper- and hypopigmentation, as well as telangiectases, the 

constellation of findings is known as poikiloderma. All forms 

of poikiloderma, irrespective of character fundamental, of 

which there are many, result from loss of dermal papillae and 

of epidermal rete ridges.

In contrast to attributes clinical of atrophy that develops 

consequent to loss of dermal papillae, atrophy clinical sec-

ondary to loss of reticular dermis is typified by a pouch that 

can be herniated with ease, a condition termed anetoderma. 

When anetoderma presents itself as papules, as occurs often 

on the back of young men with severe acne vulgaris, the con-

dition is referred to wrongly as macular atrophy (it is papu-

lar, not macular). When anetoderma presents itself as a nod-

ule (and, rarely, a tumor) of cause unknown, it was termed in 

times past “anetoderma of Schwenninger and Buzzi.”

Atrophy may involve subcutaneous fat, as well as the 

skin. When huge numbers of adipocytes are lost, as they are 

in lipodystrophy, lupus profundus, and pancreatic panniculi-

tis, a gully forms, which is just the opposite of what happens 

in anetoderma.

Anetoderma is a term generic for atrophy of the skin of 

one particular type. So called macular atrophy is one kind 

of anetoderma, but it is not a synonym for anetoderma. 

There are no “anetoderma-like skin changes”; there is either 

anetoderma or there is not. Neither is a distinction between 

“primary” and “secondary” anetoderma instructive; every-

thing is secondary to something and that applies, too, to 

anetoderma. So-called primary anetoderma is merely aneto-

derma whose cause could not be determined (idiopathic). 

All anetodermas, therefore, are “secondary” and, that being 

so; stating “secondary” is redundant. Although loss of elas-

tic tissue surely is responsible largely for the appearance of 

anetoderma (destruction of elastic fibers doubtlessly occurs 

by a process other than “elastolysis,” whatever that may 

mean), collagen, to an extent much less, is lost along with it, 

as might be expected in a condition that usually comes into 

being as a result of the effect of large numbers of inflam-

matory cells whose products do not make a distinction in 

influence destructive between kinds of connective tissue, i.e., 

elastic and collagenous, although elastic tissue undergoes 

degeneration far more readily than does collagen.

ANEURYSM: saclike dilation of a vessel.

An aneurysm is a saclike widening of a vessel, but the 

word does not tell anything about the kind of vessel affected 

or the extent of the widening, either in terms of length or 

breadth of it. It may be an artery, a vein, an arteriole, a ven-

ule, a capillary or a lymphatic. The extent of dilation may be 

very long and broad, as in an aneurysm of the aorta, or short 

and rather narrow, as in a “thrombosed capillary aneurysm,” 

which actually is a markedly ectatic venule. The aneurysm 

may be pulsatile if the vessel affected is one of the larger 



30 Review  |  Dermatol Pract Concept 2012;3(2):4

arteries of the body, it can be filled with clotted blood if the 

vessel is a vein or an artery or arteriole in a person whose 

blood pressure is low, or it may be filled with lymph if the 

vessel affected is a lymphatic. The dilation may be the result 

of weakness acquired in the wall of the vessel, as is the case 

with aortic aneurysm in cardiovascular syphilis, but it also 

may be a consequence of an error in development embryo-

logically, as in Marfan syndrome. In brief, the term aneu-

rysm itself communicates nothing about the kind of vessel 

affected, the extent of the effect, or the cause of it.

When the term aneurysm is used without qualification 

further, authors who employ it usually intend it to mean a 

saclike dilation of arteries. Nevertheless, aneurysm also is 

used to designate widening of other kinds of vessels, such 

as veins or capillaries. It is a contradiction in terms to refer 

to a cirsoid aneurysm because that proliferation of small 

blood vessels approximated closely is a hemangioma, which 

is not a saclike dilation of a single vessel. The term cutane-

ous aneurysm is imprecise because it is not the cutis which 

is aneurysmal, but an artery positioned in the skin. Dilation 

extraordinary of lymphatics in a type of “deep” lymphan-

gioma is called, rightly, caverns and not aneurysms.

ANEURYSMAL: pertaining to an aneurysm

ANGIO-: prefix pertaining to a lymphatic or blood vessel

ANGIOCENTRIC: centered around a vessel, usually a ven-

ule, but sometimes around a larger vessel.

The word “angiocentric” is not defined in most diction-

aries devoted to medical terms. Moreover, in major text-

books of dermatology and dermatopathology, no definition 

of “angiocentric” is provided.

Despite the fact that the word “angiocentric” is not 

defined in most medical dictionaries and not in any textbook 

of dermatology or dermatopathology, it is employed widely 

by authors of those textbooks. They use it to characterize 

lymphomas, inflammations, infiltrates, and “features” vari-

ous. The term also is found in the name itself of diseases, like 

“angiocentric T-cell lymphoma.” Curiously, the meaning of 

all these designations is unclear, but that should not be sur-

prising, given the reality that a definition of “angiocentric” 

never is provided. The word, literally, means “in the center 

of a vessel,” but that is not how the term is used by histopa-

thologists, they seeking to describe a pattern of distribution 

of cells, usually of nature inflammatory, or various prolifera-

tions around vessels, those cells sometimes also being present 

in the wall and in the lumen of the vessels. Furthermore, it is 

truistic to speak of angiocentricity of cells of an inflamma-

tory disease because in every instance the cells of such a pro-

cess appear first in tissue in the vicinity adjacent immediately 

to venules. In regard to malignant neoplasms, angiocentric 

T-cell lymphoma surely is not the only lymphoma in which 

T-lymphocytes are arrayed in fashion angiocentric; so, too, 

it is for mycosis fungoides, lymphomatoid papulosis, and 

adult T-cell lymphoma/leukemia, as but three examples. The 

arrangement of abnormal melanocytes of a congenital nevus 

in distribution angiocentric and adnexocentric is expected in 

that type of it referred to by us as “superficial and deep” The 

cliché “angioinvasion and angiodestruction” has become 

synonymous with changes reputed to be characteristic his-

topathologically of angiocentric T-cell lymphoma, but, as 

can be understood readily, that has no legitimacy because 

“angioinvasive” and “angiodestructive” are phenomena that 

can not be discerned morphologically; neither “invasion” 

nor “destruction” are identifiable in sections of tissue scruti-

nized through a microscope conventional.

ANGIOID: resembling a lymphatic or blood vessel

ANGIOMA: an increase in number of blood vessels or 

lymphatics, usually ones that are dilated, but not otherwise 

abnormal morphologically, in a lesion circumscribed.

Angioma is not necessarily a swelling or tumor; witness 

the tiny papule known as cherry hemangioma. Neither is it 

correct to designate an angioma; a tumor in the sense of neo-

plasm, because what is called an angioma by dermatologist 

and pathologists may be a hamartoma, a choristoma, or a 

malformation, not only a benign neoplasm, of course all are 

generically “proliferations” and this may be an easier term. 

For example, a pyogenic granuloma is a hyperplasia (it invo-

lutes in time in the absence of any treatment), a port wine 

stain is a malformation, a glomangioma is a hamartoma (it 

is composed of elements, namely, venules, glomus cells, and 

fascicles of smooth muscle, that are present normally in skin), 

and strawberry hemangioma is a benign neoplasm. Neither 

is a definition for angioma such as “an abnormal growth 

produced by the dilatation or new formation of blood ves-

sels” precise, it being applicable equally to angiosarcoma.

The term “angioma,” either with or without the prefix 

lymph- or hem-, is employed usually for lesions benign of 

character vascular, including malformations vascular like 

nevus flammeus and hemangiomas like cherry angioma. 

When authors speak of angioma without specification fur-

ther, they usually mean hemangioma, not lymphangioma. 

Nevus flammeus is a deformity of vessels that comes about 

during embryogenesis and qualifies, therefore, as a vascular 

malformation and not as a hemangioma. The same obtains 

for angioma serpiginosum; it, too, is a vascular malforma-

tion, not a hemangioma.

ANGIOMATOUS: pertaining to an angioma.

ANGIOTROPISM: not definable for purposes practical. 

Adj. angiotropic



Review  |  Dermatol Pract Concept 2012;3(2):4 31

A biological phenomenon that indicates growth or the 

turning movement of a cell or a collection of cells toward a 

vessel. In strictly morphologic sense, not definable.

The following terms should be used instead: 1. Intravas-

cular: within the lumen of a vessel. 2. Perivascular: around a 

vessel. 3. Intramural: in the wall of a vessel.

In general, the suffix–tropism implies a movement.

In biology, tropism designates the movement of an organ-

ism in response to an external source of stimulus, usually 

toward or away from it.

In medicine, tropism is used to refer, i.e., to viruses and 

other pathogens that affect only a certain host (host tropism) 

or only one specific type of cell (cell tropism).

Neither the adjective “angiotropic” nor the noun “angiot-

ropism” is defined in any of standard medical dictionary 

or in any textbook of dermatology or dermatopathology. 

Strictly speaking, the suffix–tropism implies a movement, 

the best example being the turning or bending phenomenon 

plants suffer in response to light as the environmental stim-

ulus, called phototropism. Literally, angiotropism means a 

“turning towards a vessel or having an affinity for a vessel.”

Even though a term should not be used before it is defined 

properly, angiotropism and angiotropic are used in a variety 

of different circumstances. They demonstrate that angiotro-

pic and angiotropism are not employed consistently: When 

referring to melanoma, they are used for cells that “occupy 

a pericytic location,” and authors specifically emphasize that 

there should be no evidence of intravasation in that circum-

stance. When referring to a specific type of lymphoma, so 

called intravascular lymphoma or angiotropic lymphoma 

signals exactly the opposite, namely, confinement of the 

neoplastic cells of lymphoma to a vascular lumina. Some 

authors use angiotropic synonymously with the term “angio-

invasive,” and they designate it by the presence of neoplastic 

cells within vessel walls. Yet other authors employ angiotro-

pic for inflammatory cells being present around vessels, that 

being synonymous with “perivascular,” or for inflammatory 

cells being present within vessel walls, that being a normal 

finding in any kind of perivascular dermatitis when small 

vessels are concerned, whereas it is a sign of vasculitis when 

large vessels are concerned, such as is the case, i.e., in peri-

arteritis nodosa. Meaningful definition of a term, however, 

should not be dependent on the diseases entity to which it is 

applied, but it should be clear and independent of the disease 

for which it is disposed.

Many questions remain unanswered, i.e., why is angiot-

ropism not used for distribution of melanocytes in a con-

genital nevus? Why not for neutrophils in nodular vasculitis? 

Why not for proliferations of endothelial cells of Kaposi’s 

sarcoma, which usually surround a preexisting vessel in the 

“promontorium sign”? Why not fat deposits around vessels 

such as amyloid in systemic amyloidosis? And why not for 

presence of melanoma cells within a vessel? It appears that 

authors make no clear distinctions between angiotropic and 

angiocentric; between angiotropic and angiodestructive; 

between angiocentric and perivascular, or between angiotro-

pic and intravascular.

Interestingly, the majority of usages of angiotropism in 

literature of dermatopathology refer to malignant condi-

tions, such as melanoma and lymphoma, which are known 

to be capable of spreading through sanguineous or lymphatic 

vessels. That journey of malignant cells, however, can not be 

seen through the microscope. A pathologist can only identify 

the precise location of cells in relation to preexisting vascu-

lar structures. In fact, intravascular as well as perivascular 

and angiocentric location of cells is much more commonly 

encountered in benign lesions than in malignant ones. But 

in benign lesions, we usually do not attribute any prognos-

tic meaning to these cells, whereas neoplastic cells in and 

around blood vessels are often considered to be synonymous 

with metastasis.

Dermatopathologists seem to use the word angiotropism 

only after they have come to the conclusion that a lesion is 

a malignant proliferation. Application of the term angiotro-

pism implies invariably that a dermatopathologist expects a 

certain behavior of the cells. But dermatopathologists should 

limit themselves to describing accurately what they really 

see. For this reason, the word angiotropism should not be 

used in a description of microscopic findings in sections of 

tissue. The terms intravascular, perivascular, and intramural 

are purely descriptive and therefore more accurate as stated 

earlier.

ANLAGE: in an embryo, an aggregation of cells that repre-

sent progenitors of tissue or an organ.

An anlage is an aggregation of cells in an embryo that 

signifies a stage incipient in the development of a tissue or an 

organ. Anlage is synonymous with primordium. It is impre-

cise to define anlage as “foundation of a subsequent devel-

opment” because it is not a foundation, but an initial stage 

in development (which is subsequent) and because develop-

ment does not necessarily mean formation of a tissue or an 

organ. An anlage refers specifically to that aggregation of 

cells visualizable as representing the very first stage in devel-

opment of a tissue or an organ. At about 10 weeks in the life 

of an embryo, two anlagen appear on the undersurface of 

surface ectoderm, namely, that which gives rise to the infun-

dibulo-apocrine-sebaceous follicular unit on one hand and 

that which eventuates in the eccrine unit on the other.

The word anlage is employed mostly by authors Euro-

pean, and especially ones German-speaking. Americans tend 

to use the word primordium in its stead, but, in actuality, 

that is not done very often. In fact, most textbooks of derma-

tology and dermatopathology do not provide much informa-



32 Review  |  Dermatol Pract Concept 2012;3(2):4

tion about embryology of the skin in general or structures 

adnexal (epithelia and non-epithelial) in particular.

ANNULAR: in the shape of a ring, syn, annulare.

The term anulus or annulus is Latin for little ring or fin-

ger ring, the Latin word for ring being anus. An annulus is 

circular, but the word is not synonymous with a circle; in 

terms geometric, an annulus is the region between two con-

centric circles, whereas a circle is solid. A lesion is round but 

the center is different from the border. Thus, a round lesion 

is not necessarily annular. In dermatology, the word annular 

applies to a lesion that is circular in the shape of a ring, and 

the term nummular to one that is circular and solid.

The word annular is used to describe the shape of 

lesions clinical. It is true that annular and round are dif-

ferent from one another and, therefore, should not be used 

interchangeably; in a lesion annular, the center is different 

from the periphery, whereas in a round lesion the center 

and the periphery are more or less the same. Nevertheless, 

an annular lesion is round, which means that any part at 

the circumference of it is equidistant from the center of it. 

Most lesions that are said to be annular clinically are not 

truly annular geometrically. The term annular is employed 

widely and incorrectly to designate lesions whose contour is 

closed and that may be round, oval, or polycyclic. Annular 

is used, therefore, interchangeably and wrongly with cir-

cular, circinate, arcuate, and polycyclic, none of which are 

shaped like a ring. For this reason among others, the appel-

lation “annular erythemas” is a misnomer; most lesions of 

diseases grouped under that title have configurations arcu-

ate and polycyclic, as well as annular. The term “granuloma 

annulare” derives from but a single manifestation clinical of 

that disease, namely, a papule or plaque ring like because of 

an elevated border and a depressed center. Other presenta-

tions clinical of granuloma annulare are discrete papules, 

plaques, and nodules devoid of a shape like that of a ring, 

and papules and plaques whose configuration is arcuate or 

oval, but not annular.

ANONYCHIA: absence of nail, i.e., nail plate.

Anonychia is defined correctly in dictionaries of medi-

cine as well as in textbooks of dermatology as absence of 

nails, meaning absence of nail plates. The term tells noth-

ing about the cause of that absence, which includes diseases 

of character as different as lichen planus, pemphigus vul-

garis, erythema multiform, epidermolysis bullosa dystro-

phica, infection by fungi, or effects adverse of trauma and 

drugs and even aberrations in utero that result in congenital 

absence of nails. The term anonychia is analogous to atrichia 

which designates absence of hair. The word anonychia alone 

however does not allow any conclusion to be drawn about 

the nature of the defect, i.e., injury to the nail matrix, any 

more than the word atrichia communicates anything about 

the nature of the defect responsible for it, i.e., injury to cells 

in the follicular matrix.

Anonychia is employed correctly when it designates con-

ditions in which nail plates are absent. That applies to con-

genital absence of nails, as well as to absence of nails that 

follows on inflammatory diseases (or neoplastic ones like 

mycosis fungoides) that affect the nail matrix. When the nail 

is absent or destroyed, anonychia is likely to be permanent. 

If, however, matrical cells remain visible after injury to them, 

such as occurs after episodes febrile in the extreme, then 

anonychia is likely to be transient; the nail matrix begins to 

manufacture a nail plate anew.

APHTHA: small ulcer on a mucous membrane.

An aphtha is a small ulcer that occurs on a mucous mem-

brane. It is not restricted to the oral mucosa. When aphthae 

appear concurrently in the mouth and on the genitalia the 

possibility of Behcet’s disease should come to mind. An aph-

tha is a term for a clinical feature morphologic and is not 

synonymous with a disease, namely, aphthosis. An ulcer may 

be situated on skin or on mucous membrane, whereas an 

aphtha, by definition, is confined to a mucous membrane. 

An ulcer on a mucous membrane and on skin may be sur-

rounded by a rim of redness and may be covered by a grayish 

or yellowish, exudate.

Defects in aphthosis, in primary infection by herpes sim-

plex, as well as in lesions on mucous membranes of Behcet’s 

disease, are called aphthae. The term aphthous ulcer is used 

interchangeably with aphtha, but that is redundant because 

an aphtha is an ulcer, i.e., one situated on a mucous mem-

brane. The macule, vesicle, or pustule that precedes the 

aphtha in Behcet’s disease or aphthosis is not called an aph-

tha, because an aphtha is a small ulcer, that is, a defect in 

both mucosal epithelium and lamina propria. The appear-

ance clinical and histopathological of an aphtha does not 

allow differentiation between Behcet’s disease and recurrent 

aphthosis, but the course clinical does, i.e., oral and genital 

manifestation of aphtha and/or associated symptoms of the 

eyes and of the brain signifies Behcet’s disease.

APHTHOID: similar to aphthae

APHTHOUS: relating to or characterized by aphthae

APLASIA: lack of development of a tissue or an organ.

Although “aplasia” designates lack of development of a 

tissue or an organ, it is not just a failure to develop normally; 

hypoplasia also fulfills that definition. As far as development 

in an embryo is concerned, aplasia of a tissue or an organ 

may be present at birth, but aplasia of tissue that may develop 

during the course of a lifetime, like of the bone marrow, may 

manifest itself at any time, i.e., after chemotherapy for leuke-

mia, aplasia of bone marrow may result. Even in hematology 

it is not correct to define aplasia as “incomplete, retarded, or 



Review  |  Dermatol Pract Concept 2012;3(2):4 33

defective development, or cessation of the usual regenerative 

process,” because that definition includes hypoplasia.

“Aplasia” appears almost exclusively in dermatology 

and dermatopathology in the term aplasia cutis congenita, 

a group of rare diseases congenital characterized by either 

lack in a locus discrete of skin and/or subcutaneous tissue. 

Lesions of aplasia cutis congenita may present themselves 

clinically as an ulcer at birth, but usually by that time they 

have healed with a scar that comes to be covered by a thin 

epidermis. Aplasia also may be employed for lack of devel-

opment of any kind, like that of a limb or of red blood cells.

APLASTIC: pertaining to aplasia.

APO-: prefix meaning off, away from.

APOCRINE: denoting a method of secretion whereby the 

product of a gland accumulates in the apical part of cells, 

which then detaches in a manner that has been likened to 

“decapitation,” “pinching off,” and “snouts.”

The notion of “losing cellular tissue in the process of 

secreting” is inadequate for definition of the term apocrine 

because that is what happens, too, in holocrine secretion, 

such as that of sebaceous glands in which the cell in its 

entirety becomes the product of secretion. Apocrine secre-

tion is not simply a “pinching off” of the free end of the 

secretory cell, but is separation complete of the apical part 

from the rest of the cell. That part apical of the cell is differ-

ent from the rest of it because products secretory accumulate 

there prior to the separation taking place. The apical portion 

of the cell is not incorporated in the secretion, but rather 

itself consists largely of the product secretory. Parentheti-

cally, it is illogical to say that apocrine secretion occurs in 

apocrine glands and mammary glands, because mammary 

glands are apocrine glands.

The purpose of apocrine glands is to produce a secretion, 

known colloquially as “decapitation secretion,” the exact 

role of which is not understood. The function appreciated 

best is the secretion of cells of the mammary gland, which is 

an apocrine gland, specialized to produce colostrum. Apo-

crine glands are identifiable morphologically by the apical 

part of cytoplasm giving the appearance of being “pinched 

off” or “decapitated.” An “apocrine system” per se does not 

exist; apocrine glands at different sites anatomic are spe-

cialized to produce secretion as different from another as 

“mother-milk” and cerumen. The adjective apocrine is used 

not only to denote a component of the gemisch known as a 

type of secretion, but to convey a sense for “pertaining to or 

derived from apocrine glands.” Apocrine glands are situated 

normally in the axillae, perineum, periumbilical region, and 

eyelids, and to an extent lesser, on the face and scalp.

Other clues to apocrine glands or differentiation towards 

them although not as specific as decapitation secretion 

include fringe, vacuoles in a ring at the periphery of a lumen, 

mucinous cells, signet ring cells, polygonal cells, plasma-

cytoid cells, large round granules in cytoplasm, lipofuscin, 

elongated tubules, papillations, continuity of tubules (other 

than sebaceous ductal ones) and infundibula, and the pres-

ence, in sections from the same biopsy specimen, of a ham-

artoma or neoplasm that shows follicular and/or sebaceous 

differentiation.

However, as noted earlier, the finding of unquestionable 

decapitation secretion in a proliferation, primary in the skin 

is virtually specific for apocrine differentiation.

APOPTOSIS: a type of necrosis in which cells characterized 

by pyknosis and karyorrhexis are removed by phagocytosis.

If apoptosis means “the death of cells which occurs as a 

normal part of an organism’s development,” then every kera-

tocyte that matures to become a cornified cell of the stratum 

corneum of epidermis, of the hair shaft, in the process of 

dying, which is the case for every cell, and of the nail plate 

should rightly be considered apoptotic. The “death” of any 

keratocyte could be deemed “programmed,” that is, to end 

as a dead cell, a corneocyte in the stratum corneum, in the 

hair shaft, or in the nail plate. The life span of every cell in 

the body is limited genetically, but surely not all cells are des-

ignated apoptotic. It makes no sense to invoke “requirement 

of energy of the process” as a criterion for differentiating 

apoptosis from necrosis; that requirement cannot be iden-

tified morphologically. A “deletion of selected cells in both 

physiologic and pathologic processes” also cannot be the 

basis for criteria morphologic. Characterizing apoptotic cells 

as “single homogenous eosinophilic necrotic cells (Civatte- 

or colloid-bodies),” “fragmentation into membrane bound 

particles,” or “marked by the shrinkage of the cell, con-

densation of chromatin, formation of cytoplasmatic blebs, 

fragmentation of the cell into membrane-bound apoptotic 

bodies” hardly justifies the concept; each of those findings 

are possessed by cells that in classic pathology Virchowian 

qualify as necrotic.

Controversies should rage (but do not) about definition 

of the terms “apoptosis” and “apoptotic.” The fact that defi-

nition, at times, is constructed solely on the basis of findings 

morphologic at other times on the basis of a process physi-

ological, and on the basis at other times pathologic, indicates 

how flawed irreparably is the concept of apoptosis. Mor-

phologically, cells said to be apoptotic are typified by pykno-

sis and karyorrhexis, those criteria for more than 150 years 

having been signs agreed on for necrosis. In the short space 

of 30 years, the concept of apoptosis has become accepted 

universally; despite the fact that it has never been defined 

comprehensibly. “Programmed cell death” is not a definition, 

but a phrase that conveys ignorance of principles fundamen-

tal of physiology and of pathology. Curiously, the concept 

derived initially from observation of changes affiliated with 

a process physiologic (i.e., necrosis of individual cells of the 



34 Review  |  Dermatol Pract Concept 2012;3(2):4

bulb and the stem of a hair follicle as it involutes in catagen), 

but soon was extended to findings associated with nearly 

every process pathologic in every organ, even being invoked 

as the key to pathogenesis of cancer. Moreover, apoptosis 

sometimes is used in regard to differentiation of a process 

and at other times to refer to loss of differentiation of a pro-

cess. Some authors claim that irradiation causes apoptosis 

and that the “sunburn cell” is the example stereotypical of 

an apoptotic cell, whereas others acknowledge that irradia-

tion and ultraviolet light may cause necrosis. No one has yet 

refuted the assertion that the attributes cytologic claimed to 

be identifying of so-called apoptosis, to wit, pyknosis and 

karyorrhexis are the very same ones requisite for recogni-

tion of necrosis. All of this renders it impossible to employ 

the term apoptosis in a fashion rational and meaningful, but 

apologists for the term make no effort whatsoever to respond 

to criticism of it but they proceed to expand the number of 

conditions claimed by them to be characterized by it!

APOPTOTIC: pertaining to or characterized by apoptosis.

APPENDAGES: structures produced in the skin, emerge 

from the skin, and extend beyond the surface of the skin, 

namely, hairs and nails. Matrical cells of mature hairs are 

seated in a follicular bulb and matrical cells of nails are posi-

tioned in the matrix of a nail unit.

In general, appendage is a part attached to a main struc-

ture. The term does not convey anything, however, about 

the function of the part appended, i.e., whether it is subordi-

nate or not. In dermatology, the term appendage designates 

structures that are manufactured in the skin and that extend 

beyond it, to wit, hair and nails. In contradistinction, the term 

adnexa designates epithelial (follicular-sebaceous-apocrine 

units, eccrine units, and matrix and bed of nail units) and 

nonepithelial (smooth muscles, nerves, vessels) structures that 

are housed entirely in the skin (and subcutaneous fat).

As is apparent readily, the term appendage often is 

employed when adnexal structures really are meant. The 

only true skin appendages are hair and nails, and those struc-

tures, per se, are not associated with any neoplasm; so-called 

skin appendage tumors are actually adnexal proliferations 

of the adnexa of skin (and/or subcutaneous fat); benign and 

malignant proliferations may differentiate toward epithelial 

and nonepithelial structures of adnexa.

ARBORIZATION: describes a tree-like shape that is a result 

of inward turning of epithelial structures of adnexa at the 

periphery of a structure such as a common wart, a seborrheic 

keratosis, or a pyogenic granuloma around which the change 

sometimes is called, inaccurately, an “epidermal collarette.” 

In truth, the elongated collars of epithelium are eccrine ducts 

and hair follicles, not epidermal rete ridges.

ARCHITECTURAL: pertaining to architecture.

ARCHITECTURAL ATYPIA AND ARCHITECTURAL 

DISORDER: clichés that are meaningless and, therefore, to 

be eschewed. For the term “architectural atypia” and “archi-

tectural disorder” to have meaning repeatable, there must be 

a definition agreed-on of “architectural typia” and “architec-

tural order,” but none exists. In fact, the standard for archi-

tectural typia and architectural order of skin is normal skin 

itself and, therefore, any deviation from normal skin by any 

neoplasm, benign or malignant, nevus or melanoma, quali-

fies as architectural atypia and architectural disorder, both of 

which fail to inform in general and about diagnosis specific 

in particular.

ARCHITECTURE: in general, the design, in its entirety, of 

the structure of a thing; in dermatopathology, the design of 

an abnormal condition of the skin as assessed by visualiza-

tion of the structure in its entirety and of its constituent parts.

Interestingly, neither the noun architecture nor the adjec-

tive architectural is defined in standard dictionaries devoted 

to medicine general or in any textbook of dermatology and 

dermatopathology. In the most recent edition of Dorland’s 

Illustrated Medical dictionary, architecture is defined tau-

tologically as pertaining to architectural pattern; no defini-

tion of architectural pattern is provided there. In dermato-

pathology, architecture pertains to the overall structure of 

an abnormal condition as it is assessed at scanning magni-

fication of a conventional microscope, with particular refer-

ence to each of the components, including distribution and 

arrangement of cells, as well as of noncellular constituents, 

such as fibers and deposits.

It is apparent from the quotations above that the words 

architecture and architectural are employed commonly in 

textbooks of dermatology and dermatopathology, although 

a precise definition of those terms cannot be found in any of 

them. What truly is meant by intrinsic epidermal architec-

ture, architectural atypia, or architectural disorder is impos-

sible to fathom; the terms are opaque. If such designations 

are meaningless, how can they possibly be helpful to those 

charged with responsibility for determining whether a par-

ticular neoplasm is benign or malignant? Ackerman never 

referred, ever, to “architectural atypia,” except to decry the 

use of it. He did introduce the concept of silhouette (architec-

tural pattern) of a proliferation as being the representation 

morphologic of the behavior biologic of that particular neo-

plasm and, therefore, the surest route to deciding whether 

that neoplasm is benign or malignant. He also ridiculed 

repeatedly the concept of “architectural disorder,” asking 

rhetorically how that purported phenomenon could possibly 

be identified when no one had ever supplied a definition of 

“architectural order.” For Ackerman, the word atypia never 

should be used for architecture (i.e., “dysplastic nevus”) of 

a proliferation or for an unconventional presentation of a 



Review  |  Dermatol Pract Concept 2012;3(2):4 35

common disease (i.e., “atypical pityriasis rosea”), but only 

for nuclear characteristics of cells, especially pleomorphism 

and heterochromasia (and much less so for large size and 

hyperchromasia).

ARCUATE: shaped like an arc or a bow. Syn. arciform.

In dermatology, the adjectives arcuate and arciform are 

used synonymously to describe lesions that clinically are 

shaped like either a bow or an arc. A lesion arcuate may 

come into being over time, like papules of granuloma annu-

lare become confluent, or by growth continous, such as a 

plaque of melanoma. It is imprecise to define the arcuate as 

being arranged in arches because that criterion is satisfied 

equally by the term polycyclic.

In textbooks and in articles given to dermatology and 

dermatopathology, the adjectives annular, gyrate, figurate, 

circinate, arcuate, and polycyclic often are used interchange-

ably or in conjunction with each other. In most instances, no 

definition is provided for any of them. An annulus is a ring 

or ring like structure, a gyrate lesion is circular, round, or 

spiraled, and a figurate lesion may assume any number of 

geometric shapes. Circinate means rounded, arcuate means 

formed like an arc, and polycyclic refers to a group of bow-

shaped lesions that have become confluent to form a special 

design. Annular or gyrate lesions may evolve from ones arcu-

ate or circinate (circular) or they may resolve asymmetrically, 

so that an arc or bow actually comes into existence as the 

lesion resolves. A single disease, such as urticaria, bullous 

pemphigoid in the urticarial stage of it, and mycosis fungoi-

des in the plaque stage, may express itself in the form of all 

of the shapes of lesions just mentioned.

ARRECTOR: the muscle of hair erection. Syn. arrector mus-

cle, arrector pili muscle.

Arrector has only one meaning in dermatology and der-

matopathology, namely, erection of the smooth muscle affili-

ated with a hair follicle. A designation more correct than 

muscle of hair erection is muscle of follicular erection, but 

arrector pili muscle, arrector muscle, arrector pili, or sim-

ply arrector are synonyms for it. The arrector pili muscle is 

smooth muscle that originates from bulges of the isthmus of 

hair follicles and seems to insert at the base of epidermal rete 

ridges. When the muscle contracts, a papule ever so-subtle of 

normal skin comes into being in the form of what clinically 

is called “cutis anserine” by physicians and “goose bumps” 

by laypersons.

Some hamartomas and neoplasms may consist of smooth 

muscle of follicular erection, for example, leiomyoma of one 

type (the other type being composed of smooth muscle affili-

ated with blood vessels rather than with hair follicles). The 

so-called bulge is not single a structure but rather several 

bulges of isthmic epithelium. Although the exact site of inser-

tion of the arrector pili muscle has to this day not been dem-

onstrated beyond doubt, almost certainly it is the base of 

epidermal rete ridges and not the dermal papillae. That is 

true in general for origin and insertion of muscles, to wit, 

from one type of structure to another of the same type.

ARTERIOLE: smallest of arteries that end as capillaries.

Arterioles sometimes are referred to as precapillary arter-

ies, that is, the smallest arteries of the body which terminate 

in a network of capillaries. In contrast to capillaries them-

selves, the wall of arterioles contains smooth muscle. Arteri-

oles are differentiated histologically from venules by posses-

sion of an internal elastic membrane.

Under normal circumstances, arterioles end in a network 

of capillaries, i.e., the superficial and deep plexuses of the 

reticular dermis, as well as in conditions pathologic, such as 

the hyperplasia known as pyogenic granuloma; the vascu-

lar malformation designated spider angioma and the benign 

neoplasm, referred to as cirsoid aneurysm. The number of 

layers of smooth muscle is not relevant to establishing a 

vessel as an arteriole; what matters is that it contains some 

smooth muscle.

ARTERY: a vessel that conveys blood away from the heart 

and that consists of three layers termed intima (endothe-

lium, connective tissue, internal elastic membrane), media 

(smooth muscle, and elastin), and externa (connective tis-

sue). Syn. arteria.

Artery is a vessel that conveys blood away from the heart. 

Most arteries, therefore, carry oxygenated blood except for 

pulmonary and umbilical arteries in an embryo. The wall of 

arteries usually is thicker than those of corresponding veins 

and the lumen of them is smaller and rounder. The wall of 

an artery consists of three layers, namely, intima, media, and 

externa, the latter also named adventitia. The intima is made 

up of endothelium that covers connective tissue as well as a 

more or less prominent layer of smooth muscle that is sur-

rounded by an internal elastic membrane. The media is fash-

ioned entirely of smooth muscle in arteries of the so-called 

muscular type, but it also contains elastic fibers in those that 

are found close to the heart, e.g., the aorta. The adventitia 

consists of connective tissue (collagen and elastin), and con-

tains nerves and, occasionally, blood vessels, the so called 

vasa vasorum. Sometimes, elastic fibers form an external 

elastic membrane, but that structure always is less prominent 

than the internal elastic membrane.

Artery is used correctly to designate vessels that convey 

oxygenated blood from the heart to the rest of the body. 

Arteries branch and become arterioles, which, in turn, 

become capillaries. A vascular plexus consists of arteries, 

capillaries, and veins, not of capillaries only. In the skin, the 

two plexuses in the dermis, the superficial one in the upper 

part of the reticular dermis and the deep one in the lower part 

of the reticular dermis, are connected to one another through 



36 Review  |  Dermatol Pract Concept 2012;3(2):4

“intercommunicating” vessels. Arteritis means inflammation 

of an artery, so-called arteritis temporalis being associated 

commonly with arteries that may no longer be pulsating, 

because the lumen of the vessel has been obliterated conse-

quent to the effects of the inflammatory process. Arteries in 

the skin and subcutaneous tissue always are of the muscu-

lar type, arteries of the elastic type being found only in the 

immediate vicinity of the heart. It is not necessary, therefore, 

to designate arteries in the skin “muscular.”

ARTIFACT: something that is not natural but made by 

human beings deliberately or by instruments technologic.

ARTIFACTUAL: not natural, made by human beings or by 

technology. Syn. artefactual, artificial, artifactitious, facti-

tious, facticial.

The adjective artifactual is derived from the Latin word 

arte, meaning art, and the verb facere, meaning to make, it 

designating something that comes into being by manipula-

tion of humans or by the effects of instruments of technol-

ogy. That which is present in nature never is artifactual, 

whereas findings that are pathologic may come about as a 

consequence of a “natural” process, such as one infectious, 

immunologic, or metabolic, or as a result of manipulation 

external. That being the case, as far as changes in viable tis-

sue are concerned, that which is artifactual also is patho-

logic, i.e., trichotillomania or factitious panniculitis.

Artifactual is used in dermatopathology in two different 

circumstances. First, it designates findings, clinically and his-

topathologically, that are caused by trauma inflicted by the 

person himself/herself or by another person. Trichotilloma-

nia and traction alopecia are examples of those phenomena. 

Second, all changes in sections of tissue that is introduced 

by defective technique of a physician in the course of biopsy, 

or of a machine, or of a histotech in a laboratory during the 

process of preparation of tissue are designated artifactual, 

i.e., crushing of cells during manual extraction of a specimen 

from the skin. Both usages are correct. The words artifactual, 

artificial, artifactious, artifactitious, facticious, and facticial 

are used interchangeably. Contrary to popular belief facticial 

changes in the skin may be diagnosed for what they are by 

paying attention to the criteria for them.

ASTEATOSIS: condition of slight scaliness purported to be 

“dryness” secondary to decrease in normal quantity of lipids 

in the skin.

“Asteatosis” literally means a condition in which fat is 

lacking, but that is not what dermatologists intend when 

they use it. They mean fine scaling, usually on the extremities 

and particularly on the extensor aspect of the legs, a condi-

tion they call “dry skin,” which they deem to be common, 

and which they ascribe often to “bathing too frequently” or 

to “using harsh soaps.”

Some European authors use “asteatosis” synonymously 

with “sebostasis,” although there is no evidence at all that 

the fine scaling is attributable to a decrease in secretion 

sebaceous or in sebum. Combining the adjective “astea-

totic” with the term “eczema” or “dermatitis” implies that 

an inflammatory disease of the skin is either caused by aste-

atosis (which is merely the presence of fine scales) or that 

the asteatosis results from the dermatitis, neither of those 

theses being compelling. In brief, there is no true asteatotic 

dermatitis or asteatotic eczema (see definition [actually 

absence of it] of “eczema”); asteatotic has to do only with 

subtle scaling and nothing at all to do with inflammation. 

The confusion is compounded by linking asteatotic eczema 

to eczema craquele, which has never been shown to be spon-

giotic dermatitis, and to nummular dermatitis, which is an 

authentic spongiotic dermatitis that may eventuate in spon-

giotic vesicles. In sum, if asteatotic is to be employed at all, 

it should refer only to paltry scaling that probably is physi-

ologic rather than pathologic.

ASTEATOTIC: pertaining to asteatosis.

ASTEROID: in the shape of a star, in the shape of the flower 

aster.

“Asteroid” is derived from the Greek word aster (star) 

and designates structures that have the shape or appearance 

slightly of a star. In regard to appearance histopathologic, 

asteroid refers to a structure somewhat circular associated 

with elements linear oriented centrifugally, thereby simulat-

ing the points of a star. In reality, what is termed “asteroid,” 

conventionally, by histopathologists resembles only vaguely 

a star.

In dermatopathology, “asteroid” is used mostly for bod-

ies found in macrophages, ones both mononuclear and mul-

tinucleate (histiocytic giant cell). The structures once were 

considered to be specific for sarcoidosis, but, in time, it 

became apparent that they were found in cells of granulo-

matous inflammation of all kinds. Moreover, “asteroid” is 

employed also for blastospores in sporotrichosis. In each of 

those instances, the term is utilized more or less correctly 

because “asteroid bodies,” as well as “sporothrix asteroid,” 

are reminiscent somewhat of a star.

ASYMMETRY: lack of symmetry; in dermatopathology, 

marked variation in structure of two halves of a lesion as it 

is assessed at scanning magnification of a microscope con-

ventional and in dermatology uneven distribution and shape 

of lesions on halves of the body.

Symmetry and asymmetry in dermatopathology and der-

matology usually refer to silhouette architectural of lesions 

histopathologically and distribution and shape of lesions 

clinically, the symmetry and asymmetry being assessed bilat-

erally. Bilateral symmetry means that a lesion can be divided 



Review  |  Dermatol Pract Concept 2012;3(2):4 37

by a longitudinal plane into halves that are mirror images 

of one another. Never in biology, however, is a lesion as it 

is assessed clinically or histopathologically absolutely sym-

metrical. The terms symmetry and asymmetry, therefore, are 

relative, asymmetry usually referring to differences marked 

in the “halves” of a lesion than to true “absence of symme-

try.” Interestingly, no definition of asymmetry can be found 

in any textbook of dermatopathology or of dermatology.

The terms asymmetry and symmetric are used to charac-

terize distribution and shape of lesions clinically and silhou-

ette of lesions histopathologically. Asymmetry is mentioned 

often as a criterion for malignancy, i.e., in the so-called 

ABCD rule (asymmetry, border irregularity, color variabil-

ity, diameter> 6.00 mm) for diagnosis clinical of melanoma. 

Unfortunately, that simplistic mnemonic alone does not 

work for many “pigmented lesions” of the skin, no small 

number of benign conditions, such as many congenital nevi 

and Clark’s nevi, fulfilling the criteria, and of melanoma fail-

ing to fulfill them, chief among those melanomas being those 

that develop in prepubescent children, hardly any of those 

ever being diagnosed clinically as melanoma. Considering 

the fact that asymmetry is used as a criterion histopatho-

logic for malignancy, it is surprising that no attempt has been 

made to define that word in any textbook of dermatopathol-

ogy. In sections of tissue, only two dimensions of a lesion can 

be assessed. Therefore, a lesion that seems to be symmetrical 

in two dimensions may be asymmetrical in the third dimen-

sion, which may not be visualizable in a particular section of 

tissue, that reality not being uncommon in circumstance of 

melanoma arising in association with a melanocytic nevus 

and when the blade of a microtome cuts only through that 

part of the lesion consisting of nevus, the melanoma in con-

junction with it not having been sampled.

It should be noted that symmetry or lack there of is only 

one criteria (but a major one) for the diagnosis of melanoma. 

A constellation of criteria must be used for melanoma and 

for all proliferations to determine benignancy verses malig-

nancy. Most feel there is a higherarchy of criteria. Some 

being more important then others. (e.g., Ackerman feels that 

symmetry is more important then circumsciption, etc.)

ATOPY: a genetic disposition toward development of aller-

gic rhinitis, allergic asthma, and allergic urticaria. Pruritus is 

a common symptom, and response to it by furious rubbing 

and scratching produces the skin disease known as atopic 

dermatitis.

ATRICHIA: means absence of hair. Syn. atrichiosis, atrichosis.

Atrichia is defined correctly as absence of hair, but the 

term itself does not tell anything about the reason for that 

absence, which may be congenital or acquired and may occur 

in the presence of hair follicles or in the absence of them. The 

adjective atrichial, therefore, refers to absence of hair, and 

not to absence of follicles. Although the word alopecia usu-

ally is used in common parlance of dermatology to identify 

a condition characterized by absence of hair, rarely does a 

definition of atrichia make clear the distinction between alo-

pecia (loss of hair) and atrichia (absence of hair), the terms 

not being synonymous. “Atrichia can be understood well in 

the context of its derivation from a- (absence of) and trichos 

(hair), in contrast to alopecia, which comes from the Greek 

alopex (fox), the reference being to loss of the mange of a 

fox. Not all conditions that are termed alopecia are reminis-

cent of a fox’s mange clinically, but all of them are character-

ized by loss of hair to extent various.

Rarely is the word “atrichia” employed in Textbooks of 

dermatology and dermatopathology. Some authors use it 

only to designate absence congenital of hair. Others mention 

atrichia in regard to absence of hair shafts in the presence 

of follicles, in contradistinction to aplasia in which follicles 

are lacking entirely. In fact, the word atrichia conveys noth-

ing other than absence of hair, the cause of that absence not 

being communicated, it hardly ever being identifiable clini-

cally. Alopecia areata, traction alopecia, and alopecia muci-

nosa (the latter being one of many manifestations of mycosis 

fungoides) may present themselves as atrichia.

ATROPHIC: pertaining to atrophy. Syn. atrophied

ATROPHODERMA: atrophy of skin, that is, reduction in 

amount of tissue in the dermis, especially elastic tissue but 

also often of collagen. Syn. atrophia cutis, atrophodermia.

Atrophoderma is atrophy of skin, but the loss essential to 

what is seen clinically as atrophy pertains to loss of dermis, 

not of epidermis. If, however, there is loss of dermal papillae, 

it is inevitable that that will be followed by loss of epider-

mal rete ridges. The loss of epidermis in that circumstance 

is paltry in comparison to loss of volume of dermis, and it is 

the latter which is responsible for the signs clinical of atro-

phy. An atrophoderma can be localized or widespread, as is 

the case, too, for many other processes pathologic of skin. 

Although the term has been employed for conditions like 

atrophodermia ulerythematosa or atrophoderma of Pierini 

and Pasini, the word atrophoderma does not refer to any 

specific condition per se. Atrophy has different causes and 

assumes different appearances clinically. In the majority vast 

of instances, atrophy is not a result of “improper” develop-

ment of the skin, but a consequence of the effects of products 

released from inflammatory cells, lymphocytes in particular, 

fibrocytes, which then manufacture connective tissue altered 

markedly. That is what happens in conditions like atrophic 

lichen planus and lichen sclerosus et atrophicus. But products 

of inflammatory cells, in particular neutrophils, can destroy 

fibers and hereby induce changes of atrophy in a condition 

such as cutis laxa. Anetoderma is not a synonym for atropho-

derma, but rather is one kind of atrophoderma, characterized 



38 Review  |  Dermatol Pract Concept 2012;3(2):4

by loss of both elastic fibers, and to a lesser extent collagen, in 

the upper half of the reticular dermis with resultant slackness 

in the form of a pouch. In contrast, atrophy of dermal papil-

lae leads to skin that displays a shiny surface, loss of normal 

skin markings, and facility for wrinkling easily.

Atrophoderma is used most often in dermatology for the 

atrophoderma of Pasisni and Pierini, which in actuality, is 

nothing other than a late stage of morphea. The term fol-

licular atrophoderma is a contradiction in the sense that it 

is infundibular epidermis that withers, not the dermis per se. 

Because the term “atrophoderma” is generic and does not 

refer specifically to anyone condition, and because it encom-

passes so many different manifestations morphologic of loss 

of dermis, it has little utility for parlance of dermatology and 

dermatopathology.

ATROPHY: loss of substance consequent to reduction in 

amount of tissue. Syn. atrophia

Atrophy is neither a condition in which there is failure to 

develop fully nor an alteration regressive, but one that results 

from a loss of substance. It is a term that refers to reduction, 

morphologically, in amount of tissue. The term implies noth-

ing about cause, mechanism, or type of tissue lost. It can 

occur during embryogenesis, i.e., in incontinentia pigmenti, 

or after birth, in poikiloderma vasculare atrophicans (myco-

sis fungoides) and it can follow on a process inflammatory or 

one neoplastic. Atrophy can affect the epidermis, the dermis, 

or the subcutaneous tissue, or a combination of them. When 

there is loss of dermal papillae and, subsequently, of epider-

mal rete ridges, the skin appears shiny and crinkled (superfi-

cial atrophy); when there is loss of a rather discrete zone in 

the upper half of the reticular dermis, the skin pouches out 

(midatrophy); when there is loss of adipocytes in the subcu-

taneous fat, a gully forms (deep atrophy).

So-called macular atrophy is actually papular; it is a type 

of anetoderma that comes into being by virtue of loss of elas-

tic tissue and also of collagen in the reticular dermis. Aneto-

derma is but one type of atrophy; it is not a synonym for 

atrophy. Atrophie blanche, the end stage of livedo vasculitis, 

may be atrophic, but it may be characterized only by post-

inflammatory pigmentary changes without any signs overt 

of atrophy. The best example of superficial atrophy is lichen 

sclerosus et atrophicus, of midatrophy anetoderma, and of 

deep atrophy lipodystrophy.

ATYPIA: deviation from the normal; not conforming to 

type. In histopathology, nuclei of cells that are crowded, 

pleomorphic, and heterochromatic in comparison with the 

usual appearance of nuclei of that particular type of cell. Syn. 

atypism.

The definition of “atypia” as a state of being not typi-

cal or the condition of being irregular or not conforming 

to type is based on derivation of the word from the Greek 

a- (not) and typos (type), but it does not inform much to 

a student of the subject. In pathology in general, the term 

atypia is used specifically to designate characteristics nuclear 

that are different from the appearance of nuclei of normal 

cells in regard to size, shape, and/or color, the cliché for that 

being nuclei that are “large, hyperchromatic, and pleomor-

phic.” Curiously, a definition of atypia is found but rarely 

in textbooks of dermatology, dermatopathology, and general 

pathology, although the identification of atypia is said to be 

of importance crucial for identification of proliferations as 

being malignant. Pleomorphic nuclei, hyperchromasia of 

nuclei, coarse nuclear membranes, clumping of chromatin, 

large nucleoli, an increase in ratio of nucleus/cytoplasm, 

and abnormal mitotic figures often are mentioned as attri-

butes ancillary in definitions of the term atypia. Hardly ever 

cited, however, is crowding of nuclei, which is much more 

helpful in assisting a histopathologist in regard to coming 

to diagnosis of malignant proliferations than are large size 

and hyperchromasia of nuclei. As a matter of fact, large size 

alone is of no importance in the distinction of a benign from 

a malignant proliferation; large monomorphic nuclei are not 

regarded as being atypical.

Hyperchromasia of nuclei in itself is of no benefit in 

the differentiation of a benign from a malignant process. 

For example, normal lymphocytes are so deeply blue when 

stained by hematoxylin and eosin that they seem sometimes 

to be black, and, therefore, lymphocytes never can be judged 

to be hyperchromatic. In brief, the three signs most impor-

tant of atypia in order descending are crowding of nuclei, 

pleomorphism (variation markedly in size and shape), and 

heterochromasia (variation markedly in the intensity of stain-

ing). There is no correlation direct between atypia nuclear 

and malignancy biological witness for example, the “mon-

ster” nuclei in some dermatofibromas and xanthogranulo-

mas, inflammatory conditions both and in some benign neo-

plasms like “classic” Spitz’s nevus and ancient schwannoma. 

In reverse, some malignant neoplasms are devoid of cells that 

exhibit nuclear atypia, chief among them being lymphocytes 

in the patch stage of mycosis fungoides, mesenchymal cells 

at any stage of dermatofibrosarcoma protuberans, and neo-

plastic cells of a metastasis to skin of renal-cell carcinoma.

“Atypia” is not used exclusively to designate attributes 

pathologic of nuclei. Some authors employ the term “cyto-

logic atypia” (linguistically, it would be more correct to speak 

of “atypia of nuclei” or nuclear atypia), others “architectural 

atypia” which is meaningless utterly because no definition 

has been proffered ever of “architectural typia.” Equally 

opaque are designations like atypical “classic” Spitz’s nevus, 

atypical blue nevus, and atypical fibrous histiocytoma. Cli-

nicians also have gotten into the act of “atypia” and, in the 

process, have muddled matters further. For example, der-

matologists not only refer to “atypical pityriasis rosea” and 



Review  |  Dermatol Pract Concept 2012;3(2):4 39

“atypical psoriasis” but to atypical (dysplastic) moles, bet-

ter designated Clark’s nevi, (which are the most common by 

far of all types of melanocytic nevi), to atypical (dysplastic) 

mole syndrome (which is not a syndrome because it does 

not consist of a group of signs (and sometimes of symptoms) 

that together constitute a particular .condition, but rather 

a single finding, namely a number of Clark’s nevi, and to 

atypical mycobacteria (which are atypical only because 

Mycobacterium tuberculosis was judged arbitrarily to be 

typical). It becomes apparent that recognition of atypia is 

reputed to be helpful for diagnosis of malignant neoplasms 

such as melanoma, yet a benign neoplasm of melanocytes, 

namely, “classic” Spitz’s nevus, may sport nuclei more strik-

ingly atypical than in most melanomas. It is incorrect to use 

terms like “endothelial atypia,” because it is not the endothe-

lium itself of angiosarcoma that is atypical but the cells that 

make it up. A term like atypicality is unsatisfactory because 

the noun pertaining to the adjective is atypia, not atypicality, 

and usage of the latter term for features of malignancy of a 

neoplasm adds nothing noteworthy. What is meant by “reac-

tive atypia” is mere speculation, although it is used often to 

convey a sense for atypia of cells of an inflammatory process 

(when general pathologists invoke the word “reactive,” as 

they often do, they mean “inflammatory process”), and a big 

nucleolus is not in itself a sign of atypia, it being but one 

attribute of an atypical nucleus. In dermatopathology, atypia 

should be used only to designate nuclei of cells that possess 

certain characteristics repeatable that pertain to size, shape, 

and/or color in contrast with the appearance normal of cells 

of the same particular type and for nothing else.

In conclusion, some noted dermatopathologists believe 

there really is no need to use the word atypia or atypical 

in dermatology or pathology including dermatopathology. 

Even in regard to nuclei; those can be described simply as 

being “large,” “pleomorphic,” or “heterochromatic” without 

any reference at all to atypia or atypical. The point here is to 

“say what you see.”

ATYPICAL MELANOCYTIC HYPERPLASIA: a phrase 

that is wrong conceptually and linguistically. Literally, it 

denotes an increase in fashion abnormal of melanocytes, but 

those who use the term really mean an increase in number of 

abnormal melanocytes; the “hyperplasia” is not, what they 

mean to be atypical, but rather the melanocytes themselves. 

Furthermore, what is designated “hyperplasia” actually is 

neoplasia; (although this word is also poorly defined) the 

proliferation of melanocytes does not involute, an attri-

bute essential to hyperplasia authentic. The phrase “atypi-

cal melanocytic hyperplasia” superseded “active junctional 

nevus” and preceded “pagetoid melanocytic proliferation” 

in the lexicon of evasions by histopathologists from a diag-

nosis of “nevus” or “melanoma,” it having been in parlance 

common from the mid 1960s to about 1980. Those three 

terms unconstructive were replaced in the early 1980s by 

mild, moderate, and severe “dysplasia,” that hedge being the 

one utilized most often to this day for the purpose of avoid-

ing issuance of a diagnosis direct of “nevus,” “melanoma” or 

“melanoma arising in an existing nevus” or “I do not know” 

and therefore the lesion must be removed completely. Of 

course, why one “does not know” is discussed.

AUTOECZEMATIZATION: not definable.

Not surprisingly the term “autoeczematization” rarely 

is defined in dictionaries or textbooks of dermatology and 

dermatopathology. Leider and Rosenblum assert that the 

word is synonymous with autosensitization, and that is the 

position largely of Dorland’s Illustrated Medical Dictionary 

in 2000. Its definition also is not helpful because “spread 

of lesions from a circumscribed focus of eczema” requires 

a definition lucid of eczema for the phrase to have mean-

ing and no such definition exists. Criteria morphological for 

recognition of autosensitization are not provided in any of 

the definitions just quoted. In short, the word has no place in 

dermatology or dermatopathology.

Autoeczematization” is a synonym for “autosensitiza-

tion” and for “id reaction,” and is claimed by some authors 

to be characterized by a “widespread vesicular eruption” 

typified histopathologically by “spongiotic dermatitis.” 

Other authors emphasize that the condition comes into 

being secondary to an existing “localized infectious focus,” 

(“focus of infection”) a concept that was rife in the 1930s 

and 1940s when such a focus of infection in the teeth, ton-

sils, or gall bladder was sought for any patient who had what 

was designated “autosensitization,” “autoeczematization,” 

or for “Pustular Bacterial of Andrew” (which was simply 

pustular psoriasis on palms and soles). Needless to say, der-

matologists today are loathe to recall that once a “focus of 

infection” was suspected, it was not unusual for the patient 

to be relieved of all teeth, the tonsils, and the gallbladder.

There are no criteria histopathologic for distinguish-

ing “autoeczematization” from allergic contact dermatitis, 

nummular dermatitis, or dyshidrotic dermatitis, which may 

manifest itself first as a localized eruption and later as one 

widespread that is determined by microscopy conventional 

to be spongiotic dermatitis.

AUTOSENSITIZATION: not definable.

Rarely is the term “autosensitization” ever defined and 

when it has been, the definition provided is unenlightening, 

i.e., sensitization towards one’s own tissues” and “sensitiv-

ity to one’s own cells fluids, or tissues.” Those phrases are 

reminiscent vaguely of the concept current of so-called auto-

immune diseases, but what is called “autosensitization” or 

“autoeczematization” has nothing whatsoever to do with 

lupus erythematosus and rheumatoid arthritis. Moreover, 

the term “auto-immunization” itself is opaque. That being 



40 Review  |  Dermatol Pract Concept 2012;3(2):4

true, those “auto-” words are best eschewed. See also autoec-

zematization.

The word “autosensitization” is used as a synonym for 

“autoeczematization” and “id” reaction. But no author 

makes any effort, let alone one serious, to define or explain 

any of those terms. Some authors contradict others in regard 

to description of features clinical of what they call autosensi-

tization. Equally unclear is what is meant by “dissemination 

often widespread and quick, of a previous localized eczema-

tous’ process” on one hand and presentation as “vesicular 

and on the palms” on the other. No author of a textbook 

of dermatology or dermatopathology provides criteria based 

on findings repeatable for identification morphologic, i.e., 

(clinically or histopathologically) of the condition they refer 

to as autosensitization, and no attempt is made to distinguish 

histopathologically that condition reported from allergic con-

tact dermatitis, nummular dermatitis, and dyshidrotic derma-

titis. In actuality, on grounds histopathologic alone, the four 

“entities” cannot be differentiated one from another. It is not 

an overstatement that the phenomenon autosensitization is 

“poorly understood and somewhat difficult to describe.” It 

may be that the phenomenon itself is ill-conceived.