Extra-articular diffuse-type giant cell tumour of the temporomandibular joint.

Diffuse-type giant cell tumour (DTGCT) is a benign but destructive proliferative disorder of the synovium of joint capsules, tendons and bursae. Lesions originating from the articular synovium may grow intra-articularly or expand widely extra-articularly. Rare cases may develop only in peri-articular tissues. Temporomandibular joint (TMJ) involvement is exceptional and only two cases of purely extra-articular TMJ-DTGCT have been reported. The authors report an additional case of extra-articular TMJ-DTGCT. The clinical features, histopathological characteristics, imaging modalities and diagnostic methods for DTGCT are discussed together with a literature review based on the clinical aspects of TMJ involvement.