Foamy cell angiosarcoma is a diagnostic pitfall: a case report of an angiosarcoma mimicking xanthoma.

The authors report a case of cutaneous angiosarcoma, composed predominantly of cytologically bland foamy cells, mimicking cutaneous xanthoma, dermal clear cell mesenchymal neoplasm, or clear cell dermatofibroma. The tumor occurred on the forehead and scalp of an 86-year-old white man with no history of radiation exposure. The tumor cells were positive for CD31, CD34, D2-40, FLI-1, and ERG, and were negative for CD68 and CD163. Conventional vasoformative areas, with atypia and mitoses that led to the correct final diagnosis, were found only in 1 of the 2 performed biopsies. Foamy cell angiosarcoma is probably one of the least common variants of cutaneous angiosarcoma and represents an important diagnostic pitfall.