Tophaceous pseudogout of the temporomandibular joint: report of a case.

An 85-year-old man was found to have a calcified mass protruding from the joint space of the right temporomandibular joint (TMJ). Microscopically, the removed mass consisted of chondromyxoid tissue with atypical chondrocytes, resembling a cartilaginous tumor. However, the chondromyxoid tissue contained abundant deposits of rod-shaped to rhomboid crystals which proved to be calcium pyrophosphate dihydrate (CPPD) crystals. The review of the literature revealed that tophaceous pseudogout was the most common variant of CPPD deposition disease involving the TMJ.