Synovial cyst is a cystic lesion that usually occurs in the periarticular areas of the wrists, knees and ankles, but rarely around the temporomandibular joint （TMJ）. In this report, a case with a synovial cyst that occurred around the TMJ is described. The patient was an 82-year-old woman with the chief complaint of paresthesia of the lower lip, who was referred to our department. T2-weighted magnetic resonance （MR） images revealed two continuous high signal lesions on the inner side of the left mandibular ramus and in the left condyle respectively. Fine-needle aspiration was performed via the oral cavity, and a viscous liquid was aspirated. Then, the paresthesia of the lower lip gradually improved. At 7months after the aspiration, the two high signal lesions on the MR images disappeared. The clinical course and imaging data of this case were consistent with the findings of a synovial cyst, and there was no recurrence on the MR imaging at 2-year follow-up after the aspiration.
