Dermatology: Practical and Conceptual Observation | Dermatol Pract Concept 2017;7(4):16 81 DERMATOLOGY PRACTICAL & CONCEPTUAL www.derm101.com The Patient A 66-year-old female presented to our clinic with a 12-month history of a new, growing, asymptomatic nodule on her right leg. The physical examination revealed a firm, slightly depressible, pink nodule with light brown peripheral pig- mentation and superficial visible vessels, measuring 10 mm in maximum diameter (Figure 1). Dermoscopy disclosed a central white structureless area, surrounded by an erythematous halo with areas of light brown atypical network. Additionally, fine linear-irregular and medium caliber, well-focused comma-like vessels were seen (Figure 2). Complete surgical excision of the lesion was performed. Histopathological examination revealed an intradermic nod- ular lesion with few small fusiform cells, abundant eosino- philic collagen bundles and capillary vessels (Figure 3). Immu- nohistochemistry was negative to CD34 and S100 protein. Diagnosis Atrophic dermatofibroma. Clinical Course As it is considered a benign non-melanocytic lesion, a con- servative management was proposed. No further unnecessary therapeutic procedures were performed. Discussion Dermatofibroma (DF) is one of the most common skin neo- plasms seen by dermatologists. Out of the various histopatho- logical subtypes of DF, the atrophic variant is considered rare. Clinical and dermoscopic diagnosis of DF is straightfor- ward in most cases. However, deeply atypical clinical and Nodular lesion with polymorphous vascular pattern Virgínia Coelho de Sousa1, André Oliveira2 1 Department of Dermatology, Hospital de Santo António dos Capuchos, Centro Hospitalar de Lisboa Central, Lisbon, Portugal 2 Centro Académico de Medicina, University of Lisbon, Lisbon, Portugal Key words: dermatofibroma, dermoscopy, comma-like vessels, dermatopathology Citation: Coelho de Sousa V, Oliveira A. Nodular lesion with polymorphous vascular pattern. Dermatol Pract Concept 2017;7(4):81-83. DOI: https://doi.org/10.5826/dpc.0704a16 Received: July 31, 2017; Accepted: September 8, 2017; Published: October 31, 2017 Copyright: ©2017 Coelho de Sousa 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: Dr. Virgínia Coelho de Sousa, Department of Dermatology and Venereology, Hospital de Santo António dos Capuchos, Alameda de Santo António dos Capuchos, 1169-050 Lisbon, Portugal. Tel. +351 213136300. E-mail: virginiacoelhodesousa@ gmail.com Dermatofibroma (DF) is one of the most common skin neoplasms seen by dermatologists. Out of the various histopathological subtypes of DF, the atrophic variant is considered rare. Clinical and dermo- scopic diagnosis of DF is straightforward in most cases. However, deeply atypical clinical and dermo- scopic presentations can simulate other benign and malignant tumors. We present a case of atrophic DF, describing its dermoscopic features and the correlation with histopathology. ABSTRACT https://doi.org/10.5826/dpc.0704a 82 Observation | Dermatol Pract Concept 2017;7(4):16 white scar-like patches; peripheral homogeneous area with a central white scar-like patch; or peripheral homogeneous area with a central white network; and atypical pattern [3]. Vascular structures can be present in 49.5% of DF. The most common vascular structure is erythema, followed by dotted vessels [3]. Vascular structures are one of the criteria used for the dermoscopic diagnosis of melanoma and other pigmented and vascular tumoral lesions that may simulate melanoma [4]. We present a case of a new, growing, nodular lesion pre- senting in an elderly patient. Dermoscopy showed polymor- dermoscopic presentations can simulate other benign and malignant tumors [1]. Dermoscopy is a fast, noninvasive technique that increases diagnostic accuracy for both melanocytic and non-melano- cytic skin tumors, allowing for better differentiation of clini- cal simulators of melanoma [2]. Common dermoscopic features of DF include pigment network, white scar-like patch and white network. Ten der- moscopic patterns were described, according to the presence or absence of peripheral pigment network. DF with peripheral pigment network are divided in four patterns: total delicate pigment network; peripheral delicate pigment network with central white scar-like patch; peripheral delicate pigment network with a central white network; and peripheral deli- cate pigment network with a central homogeneous area. DF without peripheral pigment network can present as total white network; total homogeneous area; total or multiple Figure 1. Clinical presentation of a nodular lesion located on the leg. [Copyright: ©2017 Coelho de Sousa et al.] Figure 2. Dermoscopic presentation with a central white struc- tureless area, surrounded by areas of light brown atypical network (arrows). Fine linear-irregular (circles) and medium caliber, well- focused comma-like vessels (arrows) were seen (polarized contact dermoscopy, x10). [Copyright: ©2017 Coelho de Sousa et al.] Figure 3. Histopathology showing an intradermic nodular le- sion with few small fusiform cells, abundant eosinophilic collagen bundles and capillary vessels (hematoxylin-eosin, x40). [Copyright: ©2017 Coelho de Sousa et al.] Observation | Dermatol Pract Concept 2017;7(4):16 83 ous tumors. Histopathological examination should always be performed in such confounding lesions. References 1. Ferrari A, Argenziano G, Buccini P, et al. Typical and atypical der- moscopic presentations of dermatofibroma. J Eur Acad Dermatol Venereol. 2013;27:1375-1380. 2. Argenziano G, Soyer HP, Chimenti S, et al. Dermoscopy of pig- mented skin lesions: result of a Consensus Meeting via Internet. J Am Acad Dermatol. 2003;48:679-693. 3. Zaballos P, Puig S, Llambrich A, Malvehy J. Dermoscopy of derma- tofibromas: a prospective morphological study of 412 cases. Arch Dermatol. 2008;144:75-83. 4. Argenziano G, Zalaudek I, Corona R, et al. Vascular struc- tures in skin tumors: a dermoscopy study. Arch Dermatol. 2004;140(12):1485-1489. 5. Kilinc Karaarslan I, Gencoglan G, Akalin T, Ozdemir F. Different dermoscopic faces of dermatofibromas. J Am Acad Dermatol. 2007;57(3):401-406. 6. Menzies SW, Kreusch J, Byth K, et al. Dermoscopic evaluation of amelanotic and hypomelanotic melanoma. Arch Dermatol. 2008;144(9):1120-1127. 7. Alves JV, Matos DM, Barreiros HF, Bártolo EA. Variants of der- matofibroma – a histopathological study. An Bras Dermatol. 2014;89(3):472-427. phous vascular structures including erythema, linear-irregular and comma-like vessels. Comma-like vessels are the dermoscopic hallmark of dermal nevi, being rarely described in DF [5]. The presence of comma-like vessels in a regular distribution or as the dominant vascular type is considered a negative predictor for amelanotic melanoma [6]. However, considering the atypi- cal clinical and dermoscopic presentation of polymorphous vascular structures described as a feature of amelanotic mela- noma, excision was mandatory to rule out this entity. Histo- pathology later confirmed the presence of a benign tumor. To our knowledge, this is the first dermoscopic descrip- tion of the rare atrophic variant of DF. Atrophic DF is identi- fied by dermal atrophy with prominent sclerotic collagen, as well as low cellularity. It has been proposed that dense elastic fibers around the vessels interfere with blood circula- tion, causing dermal atrophy, and thus low cellularity [7]. The white strutureless area seen on dermoscopy correlates with the dense collagen fibers found on dermis. Well-focused, medium caliber comma-like vessels represent superficial ves- sels running above the dermal collagen bundles. DF can thus present with a wide range of dermoscopic patterns, sometimes mimicking melanoma and other cutane-