Background: Distinguishing low and high inflammatory arthropathies of the temporomandibular joint (TMJ) and assessing the role of immune-mediation (IMM) in synovial membrane disease poses challenges due to lack of validated diagnostic criteria. The purpose of this study was to describe serologic, arthroscopic, and histopathologic findings suggestive of IMM and distinguishing findings of IMM in inflammatory arthropathies.

Methods: Chart review of 70 TMJ arthroscopy patients, performed at MGH in 2021. 62 women and 3 men met inclusion. Basic statistical analysis was performed on associations between: serology, arthroscopic and synovial biopsy histopathologic findings.

Results: A positive ANA (n=30) was most frequently associated with histopathologic findings of inflammatory infiltrates, synovial hyperplasia, or reactive synovial changes. Higher ANA titers were associated with inflammatory infiltrates (INF). Nearly one-third of patients had histologic findings of INF with lymphocytes, plasma cells, and/or chronic INF. Histologic presence of INF, without plasma cells, occurred in 20% of biopsies and was associated with arthroscopic findings of chondromalacia, adhesions, and joint stenosis.

Conclusions: These preliminary findings may represent an undefined subtype of inflammatory, IMM TMJ synovial disease. We have initiated further studies to identify molecular characteristics and validate diagnostic criteria. Development of targeted immunologic treatments for inflammatory TMJ arthropathies will follow.