Synovial Sarcoma : Intro & Sites
Synovial sarcoma (SS) is a slow growing tumor that makes up 5%-10% of all soft tissue sarcomas. It is usually seen around para-articular region of extremities in close association with joint capsules, tendon sheaths, and bursae. Despite its name, SS rarely involves the joint cavity and there is no evidence that it arises from the synovial membrane. Intra-articular synovial sarcomas make up less than 5% of all synovial sarcomas. Almost 85% to 95% of cases arise in the extremities, especially around the knee joint followed by foot, lower leg-ankle region, and hip-groin area. Tumors arising in upper extremities are evenly distributed among wrist, elbow, shoulder, and hand. After extremities, head and neck region is the next most common site of involvement and accounts for 5% to 10% of all synovial sarcomas. They occur in paravertebral space and present as parapharyngeal or retropharyngeal mass near carotid bifurcation. Uncommon locations in the head and neck region include thyroid, paranasal sinuses, parotid, and tonsil. About 5% of cases involve trunk, including chest wall and abdominal wall. Anecdotal cases have been reported in virtually every anatomic site and organ. Slide courtesy of Piero Picci, M.D., Director, Laboratory of Experimental Oncology, Instituto Ortopedico Rizzoli, Bologna, Italy. Used with permission.