Synovial sarcoma of female urethra: a case report and review of the literature.

Synovial sarcoma (SS) is a rare malignant soft tissue sarcoma that originates from primitive mesenchymal cells with epithelial differentiation potential. It is most commonly found in the limbs and trunk. In the urinary system, it is mostly found in the kidneys. However, synovial sarcomas originating from the external urethra are extremely rare. Only one case of synovial sarcoma arising from the vulvar urethral orifice has been reported previously, and we report a second case of synovial sarcoma of the urethral orifice. In addition, a total of 16 vulvar synovial sarcomas were identified and the literature are analyzed in this report reviews from 1966 to the present.