Diagnostic imaging of pigmented villonodular synovitis of the temporomandibular joint associated with condylar expansion

Pigmented villonodular synovitis (PVNS) is a rare lesion of the temporomand ibular joint. We report a case which was initially misdiagnosed as a paroti d tumor. CT revealed a well-defined mass demonstrating higher attenuation t han the adjacent soft tissue with marked expansion of the mandibular condyl e. MRI clearly delineated the extent of the lesion which had very low signa l intensity on both TLW and T2W sequences due to the effect of hemosiderin. The usefulness of these imaging procedures in diagnosis of PVNS is discuss ed.