Synovial chondromatosis of the temporomandibular joint: MRI findings with pathological comparison.

OBJECTIVES: The aim of this retrospective study was to characterize MRI findings of synovial chondromatosis in the temporomandibular joint (TMJ) by correlation with their pathological findings.

METHODS: 22 patients with synovial chondromatosis in unilateral TMJ were referred for plain MRI prior to surgical management and pathological examinations. Parasagittal and coronal proton density-weighted imaging and T₂ weighted imaging were performed for each case.

RESULTS: MRI demonstrated multiple chondroid nodules and joint effusion in all patients (100%) and amorphous iso-intensity signal tissues within expanded joint space and capsule in 19 patients (86.4%). On T₂ weighted imaging, signs of low signal nodules within amorphous iso-intensity signal tissues were used to determine the presence of attached cartilaginous nodules in pathology, resulting in 100% sensitivity, 60% specificity and 90.9% accuracy. Signs of low and intermediate signal nodules within joint fluids were used to detect loose cartilaginous nodules and resulted in 80% sensitivity, 42.9% specificity and 68.2% accuracy.

CONCLUSIONS: MRI of synovial chondromatosis in TMJ was characterized by multiple chondroid nodules, joint effusion and amorphous iso-intensity signal tissues within the expanded space and capsule. The attached cartilaginous nodules in pathology were better recognized than the loose ones on MRI. Plain MRI was useful for clinical diagnosis of the disorder.