Biphasic synovial sarcoma of oral cavity.

Synovial sarcoma is a mesenchymal spindle cell tumour, which is unrelated to synovium and shows variable epithelial differentiation. Typically, synovial sarcoma arises in the soft tissues of the extremities but cases in the head and neck region are less common and oral cavity involvement is extremely rare. A 17-year-old girl presented with a gradually increasing swelling on the right cheek for 2 years, which on biopsy, revealed a biphasic tumour comprising fascicles of spindle shaped cells with gland formation by epithelial cells and scattered masts cells. Histological diagnosis of biphasic synovial sarcoma was confirmed on immunohistochemistry by strong positivity for EMA, S-100 and CD-99 in both epithelial as well as spindle cell areas.