Synovial chondromatosis of the joint is a rare benign condition characterized by the formation of metaplastic cartilage in the synovium of the joint resulting in numerous attached and unattached osteocartilagenous bodies. Involvement of the temporomandibular joint (TMJ) is uncommon. Arthrotomy is usually applied to remove the larger particles and the affected synovial tissues. The authors report the case of a 48-year-old female with a large solitary synovial chondroma in the left TMJ. The larger mass was removed successfully via an additional incision in the anterior wall of external auditory meatus under the guidance of arthroscopy. The patient has been symptom-free for 5 years postoperatively.
Synovial chondromatosis (SC) of the joint is a rare benign condition characterized by the formation of metaplastic cartilage in the synovium of the joint resulting in numerous attached and unattached osteocartilagenous bodies . It usually affects larger joints, especially the knees. Involvement of the temporomandibular joint (TMJ) is uncommon. The main clinical features of this entity are preauricular swelling, pain, and restricted movement of the mandible. Surgical therapy is usually necessary because SC does not respond to nonsurgical treatment and does not undergo spontaneous resolution. Arthrotomy is commonly applied to remove the free particles and the affected synovial tissues . The smaller loose bodies can be removed with arthroscopy . Whether the large loose bodies can be removed arthroscopically is controversial. The authors report a case of large solitary SC of the TMJ successfully treated with arthroscopy.
A 48-year-old woman was referred in June 2003 with a chief complaint of pain in the left TMJ on opening the mouth and left preauricular tenderness. Physical examination revealed a symmetric face with no swelling of the left preauricular region, severe tenderness in the left TMJ, a maximal mouth opening of 37 mm with a slight deviation to the left, and a normal occlusion. There was clicking when she opened her mouth maximally. The patient had no history of trauma, septic arthritis or rheumatoid arthrosis. Arthrography revealed a blunt articular structure with the contrast media in the upper and lower joint space. A provisional diagnosis of disc perforation of the TMJ was given. The patient received physical therapy and arthrocentesis in the following 6 months, but she did not respond well. A subsequent MRI showed a mass with low signal foci behind the condyle in T 1 -weighted and T 2 -weighted images ( Fig. 1 ). The disc was in a normal position and no perforation was suspected. A neoplasm in the upper joint cavity was diagnosed. Exploration of the left TMJ was performed under general anaesthesia on 24 March 2004. Under arthroscopy, the articular disc was seen to be in the normal position. A 16 mm × 9 mm opalescent glistening loose body was discerned in the posterior recess of the superior joint compartment ( Fig. 2 A) . The synovial membrane was reddened and swollen, but no obvious proliferation of synovium was found. The loose body could not be removed using a cannula because of its size. A 12 mm additional incision was made in the anterior wall of the external auditory meatus. Access to the posterior recess of the upper compartment was gained with a mosquito hemostat via this incision ( Fig. 2 B). Under arthroscopic guidance, the mosquito hemostat was moved to approach and seize the loose body, which was removed through the additional incision with the hemostat ( Fig. 2 C–E). It was formed by the fusion of three particles ( Fig. 2 F). Lavage was conducted and a nearly normal view of the upper joint cavity was obtained ( Fig. 2 G). It took 15 min to complete the entire surgical procedure. Histologic examination revealed that the loose body was composed of hyaline cartilage covered by fibrous connective tissue ( Fig. 3 ). A diagnosis of SC of the TMJ was made.
At the 5-year follow-up appointment, the patient’s condition was much improved; she was able to eat a normal diet without pain. Physical examination revealed there were no tenderness and clicking in the left TMJ. Her maximal interincisal opening was 46 mm, and she had normal occlusion. There were no complications. Follow-up MRI showed no evidence of recurrence of SC ( Fig. 4 ).