Focal Pigmented Villonodular Synovitis in the Hip Joint – A Rare Case Report

Pigmented villonodular synovitis is characterized by villous/nodular proliferation of the synovial membrane affecting commonly the knee joint. Involvement of the hip ankle, shoulder, and elbow joint is distinctly uncommon. Young adults are mainly affected and present with localized pain with/without joint stiffness and swelling. Etiology thought to be due to synovial hyperplasia following chronic inflammation. The role of trauma is controversial. Radiography and computed tomography scan are not diagnostic in the early stages. MRI is useful in the diagnosis and follow-up. Histology reveals nodular proliferation lined by hyperplastic synovium beneath which are sheets of histiocytes, hemosiderin laden macrophages and osteoclast-like giant cells. Colony-stimulating factor 1 gene overexpression is seen in histiocytic cells. Syniovectomy is the mode of treatment. Total hip arthroplasty may be required for extensive disease. A high index of clinical suspicion is required to diagnose this rare disease to prevent the limitation of joint mobility and destruction.