Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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December 17, 2015
Pigmented Villonodular Synovitis of the Temporomandibular Joint
- Background:
- Pigmented villonodular synovitis (PVNS) of the temporomandibular joint (TMJ) is a rare benign proliferative disorder of the synovium.
- Clinical Presentation:
- PVNS of the TMJ presents with symptoms that include periauricular mass, trismus, malocclusion, hearing difficulties, tinnitus, and joint pain.
- Key Diagnostic Features:
- The most characteristics finding is an enlarging mass centered within the TMJ and with low signal intensity on T1-, T2-, and proton density-weighted sequences, due to hemosiderin deposition. The blooming of low signal intensity caused by the magnetic susceptibility artifact from hemosiderin in these lesions as seen on gradient echo images is nearly pathognomonic.
- CT is very sensitive in demonstrating areas of bone erosion and the extent of the tumor. Its attenuation may be slightly increased relative to muscle, owing to hemosiderin deposition.
- Differential Diagnosis:
- Synovial chondromatosis: Multiple calcified loose bodies within the joint space are characteristic
- Hemophilia: Usually affects multiple joints
- Malignant synovioma: It is almost always extra-articular and may contain calcifications
- Tuberculosis: Clumps of hemosiderin deposits are more indicative of PVNS rather than of tuberculous arthritis
- Chondroblastoma: Occurs predominantly in young people and has scattered mottled or stippled calcifications
- Treatment:
- Surgical resection
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