Synovial cell sarcoma.

Synovial cell sarcoma frequently presents as a painful periarticular mass in the lower extremity of a young male patient. The mass may appear encapsulated and is calcified in approximately 50 percent of cases. Surgery is the mainstay of therapy, with radical resection often necessary to prevent local recurrence. The maximal five-year survival rate is 40 percent. Survival is associated with small lesions, absence of metastases and histologically low-grade lesions in younger patients.