Imaging and differential diagnosis of synovial sarcoma.

Synovial sarcoma is an uncommon malignant tumor, most frequent in the lower extremity, predominantly in young males. The authors review the clinical history, the different radiographic manifestations and MR appearance of the entity. The MR findings cannot be considered specific for synovial sarcoma. A heterogeneous septated mass located close to a joint, a tendon or a bursa is most indicative of the tumor. The radiographic features of a soft tissue mass with associated calcifications and bony erosions in the lower extremity should suggest a synovial sarcoma. The most likely differential diagnoses are discussed.