Synovial sarcoma with lung metastases


Biopsy of the intra-articular knee lesion showed synovial sarcoma. The finding of a soft tissue mass with calcification close to a joint in a young patient should strongly suggest this diagnosis. 5-10% are intra-articular. Pigmented villonodular synovitis (PVNS) was considered in the differential in this case, but this is not correct as PVNS does not calcify.