Primary cutaneous epithelioid angiosarcoma: a clinicopathologic study of 13 cases of a rare neoplasm occurring outside the setting of conventional angiosarcomas and with predilection for the limbs.

Epithelioid angiosarcomas are rare aggressive neoplasms that occur most frequently in deep soft tissues. Primary cutaneous lesions are rare, and there are discrepant findings in the literature regarding their behavior. In this study, we report a series of 13 cases of primary cutaneous epithelioid angiosarcoma and analyze their clinicopathologic features. The tumors arising in the conventional settings for cutaneous angiosarcoma (ie, in the head and neck region of elderly patients, and those occurring postradiation or associated with lymphedema) were excluded. Primary cutaneous epithelioid angiosarcoma occurred in adults (mean age, 66 y) with an equal sex distribution, and presented as solitary (n=10) or multiple (n=3) nodules ranging in size from 8 to 80 mm, with a predilection for the limbs (n=10). Histopathologically, the tumors comprised infiltrative sheets of atypical epithelioid cells within the dermis with or without the involvement of the subcutis. Vascular channel formation and intracytoplasmic lumina were seen, at least focally, in most cases. Mitoses were readily identified and necrosis was seen in 40% of the cases. The tumors were immunoreactive for vascular markers, with CD31 and FLI-1 offering the highest sensitivity. Pancytokeratin was positive in two thirds of the cases, and epithelial membrane antigen was positive in one-quarter of the cases. There was rare focal expression of Melan-A (n=2) and smooth muscle actin (n=3). Follow-up information was available for 11 patients. Six patients died of metastatic disease after a median follow-up of 12 months (range, 3 to 36 mo), and 1 patient died of unrelated causes. These findings suggest that primary cutaneous epithelioid angiosarcoma occurring outside the conventional settings of angiosarcoma is a highly aggressive malignant tumor with mortality rates in excess of 55% after 3 years.