Diffuse pigmented villonodular synovitis of the temporomandibular joint diagnosed by fine-needle aspiration cytology

Diffuse pigmented villonodular synovitis is a rare tumor in the temporomandibular joint region. This article deals with a 32-yr-old male who suffered from pain and swelling in the right temporomandibular joint region associated with restricted mouth opening. Computed tomography showed a tumor lateral to the temporomandibular joint. Arthrography revealed a displaced temporomandibular joint disk. Fine-needle aspiration cytology showed characteristic cellular changes, including rounded or oval cells with abundant cytoplasm and intracytoplasmatic hemosiderin deposits and numerous multinucleated giant cells without nuclear atypia. A benign mesenchymal lesion suggestive for pigmented villonodular synovitis was diagnosed and later verified at histologic examination. Fine-needle aspiration cytology seems to be useful for this diagnosis.