Pigmented villonodular synovitis of the temporomandibular joint.

Pigmented villonodular synovitis is a proliferative disorder affecting the synovium and may be an aggressive local process with bone destruction and invasion of contiguous structures. Involvement of the temporomandibular joint is very rare. We report a rare case of pigmented villonodular synovitis of the temporomandibular joint that invaded the infratemporal fossa with bone destruction of the mandibular condyle. Magnetic resonance imaging was effective in delineating the extent of the lesion in the infratemporal fossa. Fine-needle aspiration cytology showed multinucleated giant cells and round or spindle-shaped cells with hemosiderin deposits. The tumor was resected en bloc through a combined temporocervical and infratemporal fossa approach. The postoperative histological diagnosis was a variant of pigmented villonodular synovitis. Fine-needle aspiration cytology and magnetic resonance imaging proved to be useful in the preoperative diagnosis of pigmented villonodular synovitis of the temporomandibular joint and in the preoperative planning that is required to obtain adequate surgical margins.