[Case of epithelioid sarcoma of the lower extremity]

A 26-year-old woman with epithelioid sarcoma is reported. An 8 X 4 cm mass was present in the pretibial region of the right leg. The operative specimen revealed a solid mass with necrosis and hemorrhage. Histologically, the tumor consisted of large round or oval cells with rich and eosinophilic cytoplasm and many vascular invasions. Electron-microscopically, the tumor was composed of light and dark cells. The dark cells showed abundant microfibrils in their cytoplasm compared to the light cells. We posit that the tumor was of synovial cell origin because of the presence of cytoplasmic microfibrils, pinocytotic vesicles and filopodias or microvilli-like structures.