Objective: This study aimed to investigate the inflammatory cytokine profile in the synovial fluid (SF) of temporomandibular joint (TMJ) in patients with synovial chondromatosis (SC).

Patients and methods: Ten patients with unilateral SC (SC-group) were enrolled in the study. All SC-group patients were classified into the Stage III of Milgram’s Classification because many cartilaginous loose bodies were arthroscopically detected in the superior joint compartment. The control group (CR-group) consisted of 11 volunteers who had no symptoms in the TMJ after undergoing a successful TMJ irrigation for unilateral chronic closed lock. The levels of TNF-alpha, IL-2, 4, 6, 8, 10, VEGF-A and aggrecan in the aspirated SF were compared between the SC-group and CR-group. The immunohistochemical stain of VEGF-A was also evaluated in the surgical specimen of synovial membrane with cartilaginous metaplasia obtained from some SC-group patients.

Results: The levels of IL-6, VEGF-A, and aggrecan in the SC-group were significantly higher than those in the CR-group. Other cytokines were not detected in both groups. In the immunohistochemical study, VEGF-A was strongly expressed by synovial cells around the cartilaginous nodules.

Conclusions: IL-6 and VEGF-A would contribute to the pathogenesis of SC. Furthermore, up regulation of IL-6 and VEGF with lack of the investigated anti-inflammatory cytokines (IL-4,10) suggests that intra-articular inflammatory reaction still exists even in the SC classified into the Milgram’s Stage III.

Conflict of interest: None declared.