Abstract

Synovial sarcoma is one of the most common malignant soft tissue tumors in paraarticular regions. However, it is very rare to occur without any apparent relationship to synovial or articular structures. We report a case of synovial sarcoma manifested as a subcutaneous nodule in the upper lip. A 12-year-old boy complained of a palpable tender mass in the upper lip for several months. Under the impression of a benign soft tissue neoplasm, surgical excision was done. The mass, 1.5 cm in maximum diameter, was easily separated from surrounding tissues. Microscopically, this tumor showed a characteristic biphasic pattern of synovial sarcoma. On immunohistochemical and ultrastructural studies, the tumor cells showed evidence of epithelial differentiation. There was no evidence of joint-related, primary lesions or metastatic foci. This report describes a case of synovial sarcoma arising in very unusual location and size for histologically typical synovial sarcoma.

• Keywords: Synovial sarcoma;Lip;