Epithelioid sarcoma. Enzymatic histochemical and electron microscopic evidence of histiocytic differentiation.

A 63-year-old man had epithelioid sarcoma. Light microscopy showed the tumor to resemble granuloma annulare. Enzymatic histocytochemical and ultrastructural studies demonstrated the tumor's histiocytic features. Literature review of epithelioid sarcoma and granuloma annulare showed them to have a similar anatomic distribution.