Pigmented villonodular synovitis combined with developmental hip dysplasia: a case report

Hip dislocation secondary to developmental dysplasia of the hip (Crowe type IV DDH) in adults is a debilitating condition, and associated with increased postoperative complication rate. Pigmented Villonodular Synovitis (PVNS) is an uncommon benign but locally aggressive disease, which mostly affects the large, synovium-lined joints. PVNS of hip joint accounts for 15% of all PVNS cases. But rarely, it may extend beyond the articular capsule and present as a periarticular mass. Here, we report a 67-year-old woman, who has PVNS 50 years after she was diagnosed with Crowe type IV DDH, complained of acute and persistent pain with a buttock mass coming from the right hip. Her initial presentation, diagnostic workup, and treatment will be discussed, along with a brief review of the literature.