Relapsing Polychondritis Concomitant With Synovial Chondromatosis of the Temporomandibular Joint.

Relapsing polychondritis (RP) is a rare, multisystem autoimmune disease characterized by inflammation, structural damage, and impaired function of cartilaginous tissues throughout the body. In the craniofacial region, this rare disease has been reported to affect structures of the ear and nose; however, reports of temporomandibular joint (TMJ) involvement are scarce. A second uncommon disorder of cartilage is synovial chondromatosis (SC), a progressive and proliferative disorder of the synovial membrane associated with the formation of variably sized cartilaginous and calcified loose bodies, often causing dysfunction of the joints and enlargement of the joint capsule. It commonly affects the larger joints; TMJ involvement is uncommon. We present the case of a 45-year-old woman with previously diagnosed RP in whom right TMJ pathology subsequently developed, undergoing arthroscopy and biopsy followed by arthroplasty, which was proved to be SC, likely due to her autoimmune disease. To our knowledge, this is the first case describing concomitant SC of the TMJ presumably from pre-existing RP.