"Proximal-type" epithelioid sarcoma in a young girl.

Epithelioid sarcoma is a rare, malignant soft-tissue neoplasm occurring on the distal extremities of young adults. Its histologic features consist of a proliferation of rounded to plump, spindle-shaped cells with abundant eosinophilic cytoplasm around areas of necrosis, simulating a granulomatous process. Recently a different type of epithelioid sarcoma has been described and named "proximal-type" epithelioid sarcoma. It is found mostly in the pelvic and perineal areas of young to middle-aged adults. On microscopic examination, the tumor is characterized by a proliferation of epithelioid-like cells with rhabdoid features in the absence of a granuloma-like pattern, and immunohistochemically it coexpresses vimentin, cytokeratin, epithelial membrane antigen, and CD34. As we found no report of proximal epithelioid sarcoma in the dermatologic literature, we describe an additional case in a 12-year-old girl. This type of tumor appears to be somewhat more aggressive than the classical, distal type and it should be considered in the differential diagnosis of tumors showing rhabdoid features, in particular extrarenal malignant rhabdoid tumor.