Presentation
Posterior swelling of the ankle.
Patient Data
In the posterior articular recess of the ankle, in continuity with the astragal-calcaneal joint, there's a nodule synovial hyperplasia that encroaching the Kager fat pad. Sagittal GE T2-weighted MR image shows within the mass small foci of low signal intensity that representing hemosiderin deposition (blooming artifact). No bone erosion is detectable.
Case Discussion
Pigmented villonodular synovitis is an uncommon disease characterized by hyperplastic synovium, large effusions and bone erosions. The most common differential diagnostic are hemophilic arthropathy, synovial chondromatosis, synovial hemangioma, and synovial sarcoma. Magnetic resonance imaging is effective in distinguishing this pathology because it can reveal the deposition of hemosiderin in PVNS.
Case courtesy: Dott. Francesco Filieri