Synovial chondromatosis of the temporomandibular joint: CT and MRI findings.

We report a rare case of synovial chondromatosis of the temporomandibular joint (TMJ) in a 31-year-old man. CT examination showed a mixed soft tissue mass with small calcifications near the right TMJ joint space. MR images revealed a heterogeneous mass on the different sequences and, after contrast administration, originating in the right TMJ. Cytology showed chondroid cellularity. The lesion was surgically removed and final histological study demonstrated the diagnosis of a synovial chondromatosis. We highlight the importance of the complementary findings from CT and MR, especially the important specific feature described for TMJ synovial chondromatosis related to the mixed density within the mass, in order to perform an accurate preoperative diagnosis whenever there is an absence of ossified loose bodies.