Diffuse tenosynovial giant cell tumour of the temporomandibular joint.

Tenosynovial giant cell tumour (TGCT) is a rare benign proliferative disorder of the synovium characterised by destructive invasion by synovial-like mononuclear cells. Two variants have been distinguished: a localized (TGCT-L) and a diffuse (TGCT-D) type. TGCT usually affects adults with a peak incidence in the fifth and sixth decades of life and is more often seen in women than in men. One of the most common soft tissue tumours of the hand (finger joints and tendon sheaths), it is exceedingly uncommon in the head or neck. Only three cases of TGCT-D have been described in the literature. This report presents a case of TGCT-D in the temporomandibular joint.