Untitled Observation | Dermatol Pract Concept 2015;5(2):8 57 DERMATOLOGY PRACTICAL & CONCEPTUAL www.derm101.com Case report A 75-year-old male farmer presented to a primary care skin cancer practice in West Australia with a 6-month history of an enlarging painless lesion on his left cheek with no history of any possible precursor lesion. The patient was of Italian parentage with Fitzpatrick skin photo-type 3. There was a past history of treatment of two separate squamous cell carci- nomas in-situ, one on the forehead and the other on an ear, in the previous two years. Other comorbidities included asthma, coronary heart disease, chronic obstructive pulmonary dis- ease and arthritis. There was no history of nevus sebaceous and there was neither history nor clinical signs suggestive of Cowden’s syndrome. Examination showed a single small non-pigmented nodu- lar lesion located on the left cheek in continuation with a small, pigmented macular lesion (Figure 1). Dermatoscopy (Figure 2) revealed a raised pink lesion, 3.5 mm in diameter, with a radial arrangement of vessels peripherally, with centered blood vessels in the middle of the lesion, these vessels being centered in skin-colored clods. No keratin structures (keratin scale, white structureless areas or white circles) were seen. At one edge of this lesion, in direct contact with it, was a heavily pigmented flat lesion, 1 mm in Trichilemmoma in continuity with pigmented basal cell carcinoma; with dermatoscopy and dermatopathology Moayad Al Kaptan1, Joseph Kattampallil2, Cliff Rosendahl3 1 Molescan Clinic, Cooloongup, WA, Australia 2 Clinipath Pathology, Osborne Park, WA, Australia 3 School of Medicine, The University of Queensland, Australia Key words: trichilemmoma, pigmented basal cell carcinoma, dermatoscopy, dermoscopy, dermatopathology Citation: Al Kaptan M, Kattampallil J, Rosendahl C. Trichilemmoma in continuity with pigmented basal cell carcinoma; with dermatoscopy and dermatopathology. Dermatol Pract Concept 2015;5(2):8. doi: 10.5826/dpc.0502a08 Received: February 12, 2015; Accepted: March 3, 2015; Published: April 30, 2015 Copyright: ©2015 Al Kaptan et al. 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. Funding: None. Competing interests: The authors have no conflicts of interest to disclose. All authors have contributed significantly to this publication. Corresponding author: Cliff Rosendahl, MBBS, PhD, 5 Larbonya Crescent, Capalaba, Queensland, Australia 4157. Tel. +61 419 769 970; Fax. +617 3245 3011Email: cliffrosendahl@bigpond.com A case of trichilemmoma in continuity with a pigmented basal cell carcinoma is presented with der- matoscopy and dermatopathology. The distinction between the two lesions was evident dermatoscopi- cally and was confirmed dermatopathologically. While trichilemmoma has been reported in associa- tion with basal cell carcinoma and dermatoscopy images of four previous cases of trichilemmoma have been published, no previous dermatoscopy image has been published of trichilemmoma associated with basal cell carcinoma. ABSTRACT mailto:cliffrosendahl@bigpond.com 58 Observation | Dermatol Pract Concept 2015;5(2):8 high power an eosinophilic mantle of thickened basement membrane, mimicking the outer root sheath of the hair folli- cle infundibulum, was seen. Peripheral palisading was evident adjacent to the basement membrane and extending from that there were clear cells which were banal cytologically, lacked mitosis or individual cell necrosis (apoptosis) and contained an abundant amount of glycogen within their cytoplasm. The BCC component (Figure 3 B1 and B2) showed super- ficial BCC at the dermo-epidermal junction. In the high power view melanin pigment could be seen. diameter with a pattern of pigmented lines radial, converging (Figure 2). The lesion was subjected to an excision biopsy with a 4 mm peripheral margin and submitted for dermatopathologi- cal evaluation. Dermatopathology (Figure 3) showed both the trichil- emmoma and BCC (basal cell carcinoma) components. The trichilemmoma (Figure 3 A1 and A2) was a well-circum- scribed, sharply demarcated lesion with surface papilloma- tosis, horn cysts and a degree of central desmoplasia. Under Figure 1. Clinical image of a focally pigmented nodular lesion on the left cheek of a 75-year-old man. [Copyright: ©2015 Al Kaptan et al.] Figure 2. Dermatoscopy images (polarized left, non-polarized right) of the lesion shown in Figure 1. There is a focal pigmented macular component with lines radial converging and a larger non- pigmented nodule with a radial arrangement of vessels peripherally and a centered arrangement of vessels centrally. [Copyright: ©2015 Al Kaptan et al.] Figure 3 A and B. Derma- topathology images of the lesion shown in figures 1 and 2. A1: Low power view of the trichilemmoma component showing a well-circum- scribed, sharply demar- cated lesion with surface papillomatosis, three horn cysts and a degree of desmoplasia centrally. A2: Higher power view) shows a thickened basement membrane (black arrow), peripheral palisading (yellow arrow) and clear cells (green arrow). B1: Low power view of the BCC component show- ing superficial BCC at the dermo-epidermal junction. B2: Higher power view of the BCC with low light, showing melanin pigment (arrow). [Copyright: ©2015 Al Kaptan et al.] Observation | Dermatol Pract Concept 2015;5(2):8 59 sented here are consistent with those published previously, with a radial pattern of vessels peripherally and centred ves- sels centrally. Association with a BCC is a previously reported, unusual variation, consistent with both lesions having hair- follicle derivation. This case demonstrates the utility of using a decision algo- rithm in esoteric cases with the final diagnosis to be delivered by the gold standard of dermatopathology. References 1. Tsai J-H, Huang W-C, Jhuang J-Y, et al. Frequent activating HRAS mutations in trichilemmoma. Br J Dermatol 2014;171(5):1073– 77. 2. Sano DT, Yang JJH, Tebcherani AJ, Bazzo LA de PM. A rare clinical presentation of Desmoplastic Trichilemmoma mimicking Invasive Carcinoma. An Bras Dermatol 2014;89(5):796–98. 3. Ackerman AB. Trichilemmoma. Arch Dermatol 1978:114(2):286. 4. Brownstein MH. Trichilemmoma. Benign follicular tumor or viral wart? Am J Dermatopathol 1980:2(3):229–31. 5. Sellheyer K. Basal cell carcinoma: cell of origin, cancer stem cell hypothesis and stem cell markers. Br J Dermatol 2011;164(4): 696–711. 6. Wang Y, Bu W-B, Chen H, Zhang M-L, et al. Basal cell carcinoma, syringocystadenoma papilliferum, trichilemmoma, and seba- ceoma arising within a nevus sebaceus associated with pigmented nevi. Dermatol Surg 2011;37(12):1806–10. 7. Yoon DH, Jang IG, Kim TY, Kim HO, Kim CW. Syringocystad- enoma papilliferum, basal cell carcinoma and trichilemmoma arising from nevus sebaceus of Jadassohn. Acta Derm Venereol 1997;77(3):242–43. 8. Crowson AN, Magro CM. Basal cell carcinoma arising in asso- ciation with desmoplastic trichilemmoma. Am J Dermatopathol 1996;18(1):43–8. 9. Lallas A, Moscarella E, Argenziano G, et al. Dermoscopy of un- common skin tumours. Australas J Dermatol 2014;55(1):53–62. 10. Horcajada-Reales C, Avilés-Izquierdo JA, Ciudad-Blanco C, et al. Dermoscopic pattern in facial trichilemmomas: Red iris-like structure. J Am Acad Dermatol 2015;72(1 Suppl):S30–2. 11. Rosendahl C, Cameron A, Tschandl P, et al. Prediction without Pigment: a decision algorithm for non-pigmented skin malig- nancy. Dermatol Pract Concept 2014;4(1):9. 12. Rosendahl C, Cameron A, McColl I, Wilkinson D. Dermatoscopy in routine practice— “chaos and clues.” Aust Fam Physician 2012;41(7):482–87. Conclusions Trichilemmoma is a benign tumor derived from the external sheath cells of pilosebaceous units [1] and desmoplastic trichilemmoma is a rare variant, which can present clinically with features suggesting invasive malignancy [2]. There has been controversy as to whether trichilemmomas are actually aged warts, this belief being proposed by well-known derma- topathologist Bernie Ackerman [3] but vigorously opposed by others including Marty Brownstein [4]. Basal cell carcinoma is a malignant tumor, of trichoblast differentiation but uncertain origin, although it is probably of follicular derivation [5], predilection for non-glabrous skin being consistent with this. Trichilemmoma has previously been reported in associa- tion with BCC in the context of lesions arising in a preexisting nevus sebaceous [6,7]. In addition, three cases of desmoplastic trichilemmoma arising in association with BCC without a preexisting nevus sebaceous have been reported [8]. The dermatoscopy of four trichilemmomas has been reported [9,10] with images being presented for three of them [10]. In the first case reported, without a photograph, the dermatoscopic features were described as “keratin masses; perivascular whitish halos” [9]. The other three were reported together, with the first two described as having a hyperkera- totic central area with peripheral erythematous radial lines, the third having a “peripheral radiated red area.” All three were then presented as depicting what the authors called a “red iris like structure.” Examination of the photographs published in fact displayed a non-pigmented lesion in each case with a radial arrangement of vessels peripherally and structureless white centrally with some centred vessels [11]. In the case we report, the clinician interpreted the lesion as a pigmented lesion and assessed it using the chaos and clues decision-algorithm [12]. The lesion was regarded as chaotic (asymmetrical) with the clues of an eccentric structureless (pink) area as well as lines radial segmental, which lead to a clear decision to do an excision biopsy. The pathologist, as is often the case with esoteric lesions, was able to deliver the answer to which particular type of malignancy this was. The dermatoscopic features of the trichilemmoma pre-