Temporomandibular joint synovial chondromatosis with a giant cell component.

Synovial chondromatosis is a benign locally aggressive neoplasm that rarely affects the temporomandibular joint (TMJ). This report describes a case of synovial chondromatosis in a 34-year-old woman presenting TMJ pain and mandibular deviation with limited mouth opening. Imaging examinations revealed multiple calcified masses within the TMJ. During surgery, cartilage fragments were easily detached. On histological examination, multiple coalescent nodules of hyaline cartilage with areas of endochondral ossification and mild cell pleomorphism were observed, together with a significant giant cell component within a chondroid matrix. The presence of giant cell infiltration in synovial chondromatosis is extremely rare, leading to a differential diagnosis that included osteogenic, chondrogenic, and giant cell-rich tumours.