A 34-year-old male patient presented with a gradual facial asymmetry and occasional discomfort in the right temporomandibular joint (TMJ). Initial evaluation, including panoramic radiography, suggested facial asymmetry secondary to condylar elongation. However, computerized tomography and magnetic resonance imaging demonstrated the existence of a condylar mass and multiple calcified lesions within the right TMJ. The patient did not recognize any occlusal changes, but it was suspected that the occlusion had changed based on the cast analysis. The patient underwent a condylectomy and mass excision, which confirmed the diagnosis of osteochondroma with concurrent synovial chondromatosis. Approximately three weeks of postoperative physical therapy were required to achieve stable occlusion. This case is notable for two reasons. First, the simultaneous occurrence of osteochondroma and synovial chondromatosis is extremely rare. Second, the gradual occlusal changes associated with TMJ lesions can go undetected, increasing the chance of misdiagnosis.

• 신승은(원광대학교 치과대학 산본치과병원 구강악안면외과) | Seung Eun Shin (Wonkwang University College of Dentistry, Sanbon Dental Hospital, Department of Oral and Maxillofacial Surgery, Republic of Korea)
• 남정우(원광대학교 치과대학 산본치과병원 구강악안면외과, 원광대학교 치과대학 원광치의학연구소) | Jung Woo Nam (Wonkwang University College of Dentistry, Sanbon Dental Hospital, Department of Oral and Maxillofacial Surgery, Republic of Korea, Wonkwang Dental Research Institute, College of Dentistry, Wonkwang University, Republic of Korea) Corresponding author