Bone involvement in synovial sarcoma

Eighteen cases of synovial sarcoma are described showing radiological evidence of bone involvement. They were chosen from a total series of sixty-five synovial sarcomas. Detailed descriptions of the X-ray appearances are given. Cases showing pressure atrophy of bone without other changes were not included. A classification into broad groups is suggested.

Various conclusions are drawn and a brief differential diagnosis is offered based on the appearances of the cases presented. It is emphasized that the joint is often not involved, that joint effusions are exceptional, and that these tumours may involve bone remote from a neighbouring joint.

It is thought that the so-called ‘typical appearances’ are not necessarily the most frequent manifestation of bone involvement, but that where there is osteolysis or periosteal proliferation in a bone showing pressure atrophy then synovial sarcoma is a likely diagnosis. Adjacent bones frequently show secondary changes. Soft-tissue calcification, although useful in diagnosis, is too infrequent to be of great value.

Metastasis to bone is not uncommon in synovial sarcoma, and one such case of particular interest is described.