Abstract: Objective：To give a reference for the early diagnosis and treatment of the cysts arising from the temporomandibular joint. Methods: Nine patients finally diagnosed as temporomandibular joint cysts at the Peking University Hospital of Stomatology from May 1998 to August 2013 were selected and reviewed. Their clinical manifestations, imaging features, diagnoses and differential diagnoses, treatments and followups were summarized and discussed. Results: In the 9 patients, 3 were males and 6 females. Their ages ranged from 33 to 62 years with a median age of 39 years; the course of the disease ranged from 2 weeks to 3 years with a median of  4 months. The image examinations were performed with conventional X-ray examinations in 7 cases, CT scans in 8 cases, MRI in 6 cases and ultrasound in one case. Of the 9 cases, 7 were finally diagnosed as ganglion cyst and 2 as synovial cyst. Ganglion cysts mainly presented as the mass of preauricular area or joint area, with no obvious symptoms or only local discomfort, occasionally with pain. The synovial cysts manifested as the painful swelling of preauricular area and limited mouthopening, accompanying with occlusal disorders. The treatments included surgical resection in 8 cases, repeated arthrocenteses and lavages in one case. The follow-ups were from 3 months to 9 years, one case with recurrence, and the remaining eight cases without recurrence. Conclusion: MRI examinations are very helpful in the early diagnosis and treatment planning of temporomandibular joint cysts. Surgical resection can have good results. Repeated arthrocenteses and lavages also have a good result, which may be an alternative choice for synovial cyst, but more accumulation of clinical experience is further needed.

Key words: Temporomandibular joint, Ganglion cyst, Synovial cyst