Chondrosarcoma of synovium has been described. There is controversy as to whether malignant degeneration takes place leading to a secondary malignant process. However, there have been at least 19 well documented cases of such a secondary malignant process. Unfortunately, there are no clear cut radiological studies that can differentiate the entities. Metastasis is the hallmark of malignancy and pulmonary spread was present in 7 of the 19 cases.
Symptoms develop form the irritation of the synovium and mechanical properties of the loose bodies.
The process is insidious and may go on for years before being diagnosed. Once diagnosed removal of the loose bodies with synovectomy provides the best chance for eradication of the disease. In the presented case of this 8 year old boy, close follow up is necessary to diagnose recurrence and hopefully minimize the risk of degenerative arthritis.