Biomarker expression related to chondromatosis in the temporomandibular joint.

Background: Synovial chondromatosis is usually detected at a late stage based on free bodies in joint space. The purpose of this study was to identify biomarkers for cell proliferation and chondrogenesis in the primary stage of synovial chondromatosis in the temporomandibular joint (TMJ).Clinical Presentation: A 67-year-old female was referred for right side TMJ pain. Magnetic resonance imaging (MRI) findings suggested an intra-joint space lesion, but no free bodies were observed intraoperatively. Pathological examination led to diagnosis of Milgram stage 1 synovial chondromatosis. Biomarkers related to mesenchymal stem cells (MSCs), cell proliferation, and chondrogenesis were observed in immunohistopathological examination of specimens.Clinical Relevance: The findings suggest that MSCs with chondrogenic potential and growth activity are present at the start of cartilage formation in the synovial membrane. These cells may be the origin of disease. Those findings improve understanding of the etiology and disease progression of synovial chondromatosis in the TMJ.