Challenges in distinguishing chondrosarcoma from synovial chondromatosis of the temporomandibular joint

Chae, Jong-Seong; Leem, Dae Ho; Ku, Jeong-Kui

doi:2026.64.7.259

J Korean Dent Assoc > Volume 64(7); 2026 > Article

Case Report

Journal of Korean Dental Association 2026;64(7):259-264.
DOI: https://doi.org/10.22974/jkda.2026.64.7.005 Published online July 31, 2026.

Challenges in distinguishing chondrosarcoma from synovial chondromatosis of the temporomandibular joint

Jong-Seong Chae¹

, Dae Ho Leem¹

, Jeong-Kui Ku^1,2

¹Department of Oral and Maxillofacial Surgery, School of Dentistry, Jeonbuk National University, Jeonju, Korea
²Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam, Korea

Correspondence: Jeong-Kui Ku, Tel: +82-31-787-2780,
Email: kujk@snubh.org

Received: 16 March 2026 • Revised: 8 June 2026 • Accepted: 15 June 2026

Abstract

Synovial chondromatosis is a rare benign disorder that can closely mimic chondrosarcoma, particularly in the temporomandibular joint (TMJ), where both conditions are uncommon. We report a diagnostically challenging case of an 81-year-old female presenting with preauricular pain, swelling, and limited mouth opening. Radiologic evaluation, including computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography-computed tomography (PET-CT) revealed multiple calcified loose bodies, condylar erosion, and a poorly defined mass, initially suggesting synovial chondromatosis. Surgical intervention was performed under the assumption of a benign lesion. However, histopathologic examination demonstrated high-grade (grade III) chondrosarcoma with marked cellular atypia and increased mitotic activity. This case highlights the limitations of relying solely on clinical and radiologic findings for diagnosis. Accurate differentiation between synovial chondromatosis and chondrosarcoma requires comprehensive evaluation, including histopathologic confirmation. Clinicians should maintain a high index of suspicion when atypical or aggressive imaging features are present in TMJ lesions.

Key Words: Chondromatosis, Synovial; Chondrosarcoma; Temporomandibular Joint; Diagnosis, Differential