Synovial cysts of the temporomandibular joint are rare. They commonly occur in the wrist, knee and feet. The main symptoms of synovial cysts occurring in the temporomandibular joint include preauricular pain and swelling, and surgical removal is the gold-standard treatment. A 54-year-old woman who presented with swelling of the right temporomandibular joint visited Kyungpook National University Dental Hospital. She had undergone enhanced computed tomography from another hospital, which showed a 1.1 × 0.8 × 1 cm well-defined rounded cystic lesion on the lateral area of the right temporomandibular joint. A synovial or ganglion cyst was suspected. The cystic lesion was surgically removed under general anesthesia and was histopathologically diagnosed as a synovial cyst. Histopathological findings show a lumen surrounded by loose fibrous tissue, and the lining is in a folded form and is composed of synovial cells.

Ⅰ. INTRODUCTION
Ⅱ. CASE REPORT
Ⅲ. DISCUSSION

• 박재홍(경북대학교 치과대학병원 구강악안면외과학 교실) | Jae-Hong Park (Department of Oral and Maxillofacial Surgery, Kyungpook National University Dental Hospital, Daegu, South Korea)
• 김도형(경북대학교 치과대학병원 구강악안면외과학 교실) | Do-Hyoung Kim (Department of Oral and Maxillofacial Surgery, Kyungpook National University Dental Hospital, Daegu, South Korea)
• 최소영(경북대학교 치과대학병원 구강악안면외과학 교실) | So-Young Choi (Department of Oral and Maxillofacial Surgery, Kyungpook National University Dental Hospital, Daegu, South Korea)
• 이성탁(경북대학교 치과대학병원 구강악안면외과학 교실) | Seong-Tak Lee (Department of Oral and Maxillofacial Surgery, Kyungpook National University Dental Hospital, Daegu, South Korea) Corresponding author