Odyssey of an elbow synovial chondromatosis.

Synovial chondromatosis of the elbow is an uncommon condition. However, a chondrosarcoma arising from the former is remarkably rare. The authors report a case of an elbow chondrosarcoma secondary to synovial chondromatosis in a 38-year-old woman. Before the development of chondrosarcoma, the patient underwent 3 operations and 3 sessions of radiosynovectomy because of continuous recurrence of synovial chondromatosis on the left elbow. After the last radiosynovectomy, magnetic resonance imaging and biopsy showed a grade II chondrosarcoma secondary to synovial chondromatosis. The patient underwent further surgery and custom-made arthroplasty because of aseptic loosening of the prosthesis. Four months after the last intervention, 3 subcutaneous nodes appeared on the patient's elbow and were histologically found to be a recurrence of chondrosarcoma (grade III). Amputation by disarticulation of the shoulder was performed in addition to biopsy of another subcutaneous node on the abdomen. The biopsy showed metastasis of chondrosarcoma. At final follow-up, the patient had lung metastasis 7 years after the initial diagnosis. A reason for the manifestation of primary synovial chondromatosis and its progression to chondrosarcoma has not been found. Synovial chondromatosis progressing to chondrosarcoma in the elbow was reported in only 1 case, with no clear initial diagnosis. The role of radiosynovectomy in the development of chondrosarcoma is unknown, and no reports have described the treatment of elbow synovial chondromatosis. Although synovial chondromatosis is benign, its metaplastic nature is a marker of possible malignancy, especially with signs of recurrence and aggression. The role of radiosynovectomy in malignant changes should be examined in future studies.