Dermoscopic features of aneurysmal dermatofibroma: A case report and review of the literature

Dear Editor, Aneurysmal dermatofibroma (ADF), also known as aneurysmal fibrous histiocytoma, is a relatively rare form of dermatofibroma (DF), accounting for less than 2% of all cases.1,2 Only a few reports have addressed the relation between the dermoscopic and histopathological findings of ADF. We report a case of ADF with detailed dermoscopic presentations. A 61yearold woman was referred to our department for a nodule on the left cheek with a 2year history (Figure 1a). Clinical examination found a soft, black, immovable nodule of 14.0 mm × 7.0 mm. Her past history showed no significant trauma to the area. Dermoscopy with polarized light revealed a diffuse bluish or reddish homogeneous area with white linear structures (Figure 1b). We observed scarlike white patches and peripheral delicate pigment networks. Based on the observations above, we suspected the lesion to be a fibrous tumor, adnexal tumor, hemangioma, or malignant tumor including melanoma. The surgical specimens showed distinct abnormal spindled histiocytes and fibroblasts in the dermis (Figure 1c). The extravasation of erythrocytes and the proliferation of capillaries were recognized (Figure 1d). The brown deposits were positive for Berlin blue (Figure 1e) but negative for FontanaMasson (Figure 1f), indicating that those deposits were hemosiderin. The cells were positive for CD68 (Figure 1g) and CD163 (Figure 1h), but negative for MelanA (Figure 1i), HMB45, SOX10, AE1/AE3, CD34, D240, αSMA, S100, and desmin (not shown). The Ki67 index range was between 10% and 20%. Taken together, the diagnosis of ADF was made. No recurrence has been observed for eight months. Zabballos et al.3 reported a redbluish homogeneous area with white structures and a peripheral delicate pigment network with vascular structures as common dermoscopic findings of ADF, which