Magnetic resonance appearance of intra-articular synovial sarcoma: case reports and review of the literature.

Intra-articular synovial sarcoma is extremely rare. The authors report the magnetic resonance appearance of 2 cases of intra-articular synovial sarcoma and review the current medical literature on this subject. Intra-articular synovial sarcoma must be considered in the differential diagnosis of a heterogeneously enhancing multiloculated intra-articular mass, especially in the knee joint, that does not have the typical radiological features of either synovial osteochondromatosis, pigmented villonodular synovitis, or synovial hemangiomas.