Synovial Chondromatosis Identified on TMJ Evaluation

A 74-year-old female with a history of cancer was referred for TMJ evaluation by a clinician at a TMJ and sleep practice. The clinician suspected the significant bony changes observed were related to degenerative joint disease (osteoarthritis) and requested a second opinion given the patient's oncologic history. In addition to an osteophyte at the anterior aspect of the condyle, the radiologist identified a large loose ossified body at the posterior aspect of the right condyle. Comparison with prior imaging revealed the ossified body was not present on a 2017 study but had developed by the time of a 2022 scan, and it was associated with malocclusion and a dental midline shift to the left. The radiologist noted that these findings are suggestive of synovial chondromatosis, a rare condition, rather than routine degenerative joint disease. This distinction is clinically significant because the two conditions require different treatment approaches: degenerative joint disease may be managed with splint therapy or observation, while synovial chondromatosis requires surgical removal of the loose bodies and abnormal synovial tissue. If not properly identified and treated, synovial chondromatosis can lead to further joint destruction, occlusal changes, facial asymmetry, and possible extension into the middle cranial fossa.