Adult onset polyarticular pigmented villonodular synovitis

Pigmented Villonodular Synovitis (PVNS), typically, presents as a chronic monoarthritis affecting medium to large joints or tendon sheaths. Polyarticular presentation of PVNS is extremely rare, mostly reported in children and has not yet been reported in adults. We report a case of polyarticular PVNS, presenting in adulthood. We made the diagnosis based on characteristic MRI findings and typical histopathological changes. Patient was successfully managed with synovectomies and was not subject to inappropriate DMARDs. We suggest, that PVNS should be considered in the differential diagnosis of seronegative polyarthropathy, to avoid a delay in diagnosis and consequent delay in appropriate treatment. To our knowledge, this is the first case report of PPVNS presenting in adulthood, and serves as an example of atypical presentation of a rare condition.