Synovial chondromatosis of the temporomandibular joint.

Synovial chondromatosis is a benign, chronic, progressive synovial metaplasia that will not resolve spontaneously. Although it is non-neoplastic, the condition can be easily mistaken histologically as malignant. Seven patients with synovial chondromatosis involving the temporomandibular joint have been seen at the Mayo Clinic; two of these have been described previously. Of the remaining five, four have had the lesions evaluated histologically. The fifth patient, recently treated at the Mayo Clinic, has had no recurrence of symptoms a year after surgery.