Untitled Quiz | Dermatol Pract Concept 2015;5(3):6 25 DERMATOLOGY PRACTICAL & CONCEPTUAL www.derm101.com Clinical presentation A 61-year-old white female presented with a 7 x 4 mm nodule that was firm to palpation on her right leg (Figure 1) of 5 months’ duration. The lesion was not painful, but bleeding with minimal trauma. Dermoscopic appearance The main findings were milky red-white areas, ulceration and atypical vessels on the palpable component and two pigmented areas at the periphery that were asymmetrically distributed (Figure 2). Dermatoscopy: A nodule on a woman’s leg Ramon Pigem1, Susana Puig1, Lidia Maroñas-Jiménez2, Josep Malvehy1 1 Melanoma Unit, Department of Dermatology, Hospital Clinic, IDIBAPS, Universitat de Barcelona, Barcelona, Spain 2 Department of Dermatology, Hospital Doce de Octubre, Madrid, Spain Citation: Pigem R, Puig S, Maroñas-Jiménez L, Malvehy J. Dermatoscopy: A nodule on a woman’s leg. Dermatol Pract Concept 2015;5(3):6. doi: 10.5826/dpc.0503a06 Copyright: ©2015 Pigem 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. Corresponding author: Ramon Pigem, MD, Melanoma Unit, Department of Dermatology, Hospital Clinic of Barcelona, C/Villarroel 170, 08036 Barcelona, Spain. Tel. +34 932279867; Fax: +34 932275438. E-mail: rpigem@clinic.ub.es Figure 1. The lesion is located on the right leg, just below the right knee. It is an asymmetrical erythematous plaque with ill-defined bor- ders. The pigmented area is attached to a palpable and ulcerated nodule. [Copyright: ©2015 Pigem et al.] Figure 2. Asymmetry in its structures with a palpable area (right side of the picture) that presents atypical vessels and ulceration is seen. On the other side (left), adjacent to the nodule, a delicate pigmented area may be observed. [Copyright: ©2015 Pigem et al.] 26 Quiz | Dermatol Pract Concept 2015;5(3):6 have been already reported [1]. Even though dermoscopy may be useful in the recognition of compound tumors, some cases may be more difficult to recognize. In the present case the main differential diagnosis was melanoma. Amelanotic/ hypomelanotic melanoma is characterized clinically by the presence of asymmetry and ulceration, whereas irregular pig- mentation and certain vascular patterns (milky-red areas and dotted and linear irregular vessels) are commonly seen in the dermoscopy of these tumors, similar to the present case [2]. References 1. Zaballos P, Llambrich A, Puig S, et al. Dermoscopy is useful for the recognition of benign-malignant coumpond tumours. Br J Dermatol 2005;153:653-6. 2. Zalaudek I, Kreusch J, Giacomenl J, et al. How to diagnose non- pigmented skin tumors: a review of vascular structures seen with dermoscopy: part I. Melanocytic skin tumors. J Am Acad Dermatol 2010;63:361-74. What is your diagnosis? Diagnosis The lesion was totally excised to rule out malignancy with a final diagnosis of a compound tumor. The nodule with erosion and atypical vessels corresponded to an infiltrating basal cell carcinoma (Figure 3), whereas the firm area with pigmentation to a dermatofibroma (Figure 4). Discussion A compound (collision) tumor is the result of two different neoplasms occuring in the same lesion. Correct diagnosis is important in order to offer proper treatment when benign and malignant lesions coexist. In the literature several compound tumors and their dermoscopic features, including the asso- ciation between dermatofibroma and basal cell carcinoma, Figure 3. Compound tumor. The histopathologic analysis revealed an infiltrating basal cell carcinoma. Erosion is observed on the tu- mor surface (epidermis) and a tumoration of small basophilic cells forming micronodules and infiltrating cords with peripheral pali- sading surrounded by stroma is observed. There is also an inflam- matory infiltrate (hematoxilin and eosin stain 10x). [Copyright: ©2015 Pigem et al.] Figure 4. Compound tumor. The other tumoral component of this lesion was a dermatofibroma. A not very well defined dermal tu- moration of fusocellular cells with epidermal hyperplasia and hyper- pigmentation of the basal layer are seen (hematoxilin and eosin stain 10x). [Copyright: ©2015 Pigem et al.]