Synovial chondromatosis (SC) is a metaplastic disorder characterized by the formation of cartilaginous nodules inside the articular space. SC is uncommon in the temporomandibular joint (TMJ). A few reports suggest a correlation between a traumatic episode and the development of SC. The authors describe the diagnosis, treatment and follow-up of a patient with unilateral SC of the left TMJ in conjunction with bony resorption on the mandibular condyle and a clear traumatic etiology. They review and comment on previous reports in the literature.
Synovial chondromatosis (SC) is a rare condition in which there is cartilaginous metaplasia of the mesenchymal remnants of the synovial tissue of the joints, it is more of an active metaplastic process than a neoplastic one. SC is characterized by the formation of cartilaginous nodules in the synovium and inside the articular space (loose bodies). Usually only one joint is involved; this is most often the knee, and less commonly the hip, elbow, wrist, ankle or shoulder, although the temporomandibular joint (TMJ) may also be affected. The etiology of SC is unknown, but possible causes could be trauma, rheumatoid arthritis or other forms of inflammatory joint disease. The case described here presents a well-documented case for the traumatic origin of SC.
A 50-year-old man was referred with a history of facial trauma stemming from a bicycle accident. Radiological examination revealed a non-displaced fracture of the left mandibular condyle ( Fig. 1 ), which was treated by closed reduction and intermaxillary elastic fixation. After removal of the intermaxillary fixation, the patient had an uneventful postoperative course with improvement of his occlusal deficit and no pain.
2 years later the patient returned with a complaint of severe pain in left preauricular region and a presumptive diagnosis of post-traumatic arthritis. He reported swelling of the left preauricular area that had been evident for 2 months ( Fig. 2 A) and limitation of mandibular opening (20 mm) with deviation to the right side. On examination, the left TMJ area was swollen and crepitant, with a hard mass of about 3 cm × 3 cm. Facial nerve function was intact and there was no evidence of palpable cervical lymphadenopathy. Diagnostic imaging was performed with panoramic radiography that confirmed complete healing at site of the previous fracture ( Fig. 2 B). Computed tomography (CT) showed erosion of the left condyle, with slight bone destruction, but no destruction of the glenoid fossa or temporal bone, and an expanded articular cavity ( Fig. 2 C). Magnetic resonance imaging (MRI) revealed multiple nodules inside the superior articular cavity of an expanded TMJ, with obliteration and severe displacement and destruction of the articular disc. There was distension of the capsule and fluid in the TMJ ( Fig. 2 D).
Under general anesthesia, a preauricular incision was performed with exposure of the left TMJ ( Fig. 3 A) . The distended lateral capsule was incised and both upper and lower compartments were explored. Straw-colored synovial liquid was aspirated at operation and discectomy and high condylectomy were performed with removal of a conglomerate of 35 irregular loose bodies ( Fig. 3 B). The nodules were of a pearly white or pink hue, of varying shape and ranging in size from 2 to 10 mm ( Fig. 3 C). Condylar shaving was performed for the slight bone destruction associated with this case. The wound was drained and closed in layers. The postoperative course began with immediate articular physiotherapy after 2 days. A Michigan splint was applied at night to improve TMJ function and masticatory muscle relaxation. The patient was discharged on the fifth day postoperatively.
Histopathological examination confirmed SC. The nodules were of cellular hyaline cartilage covered by a fine fibrous layer, and sometimes by synovial lining cells without focal osteoid formation ( Fig. 4 ).
2 years later the patient reported no pain and no limited jaw movements, with 48 mm of mouth opening and no deviation. Diagnostic imaging showed no local recurrence after total removal of the lesion.