Abstract

Cutaneous angiosarcoma is the most common form of angiosarcoma. Classically, angiosarcoma has been described in three distinct clinical scenarios; typically head & neck of older adults, postoperative radiotherapy, and chronic lymphedema. The histomorphology is diverse and the so called “foamy cell variant” is extremely rare with less than five cases described in literature till date. This case is of an 88 year-old man with an initial biopsy described as purpura r/o nevus, and subsequent sampling of a 10 x 7 cm plaque. Initial superficial shave biopsy of the frontal scalp showed scattered irregular superficial dermal vessels lined by plump endothelial nuclei. A moderately dense lymphocytic infiltrate, extravasated erythrocytes and occasional foamy histiocytes were noted, diagnosed as benign hemangioma. In four months, the lesion progressed and additional punch biopsies from the vertex scalp showed infiltrative mononuclear cells with vacuolated/foamy cytoplasm (resembling foamy histiocytes). There were also irregular vascular spaces lined by spindled to epithelioid cells with hyperchromatic nuclei dissecting collagen bundles. A background mixed infiltrate, extravasated erythrocytes and hemosiderophages was noted. Tumor (foamy cells included) was highlighted by CD31, ERG, patchy D2-40, CD34, and CD10 while negative for HHV8, SOX10, S100, pancytokeratin and CD163 necessitating the diagnosis of angiosarcoma, foamy cell variant. The histomorphology of the foamy cell variant of angiosarcoma appear banal hence, can be misdiagnosed as a benign vascular neoplasm. A high clinical and histopathologic index of suspicion is needed to appropriately sample and carefully examine these extremely rare lesions to prevent underdiagnosis and subsequent mismanagement of patients.

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