[Diagnosis and surgical therapy of diffuse pigmented villonodular synovitis of the hip joint].

Pigmented villonodular synovitis (PVNS) of the hip is a monoarticular proliferative process involving the synovial membrane. A chronic inflammation as well as a neoplastic process have been proposed in the literature. PVNS is usually found in adults aged 20-50 years, without sex predilection. The knee is by far the commonest location, followed by the hip. We present a detailed case report of a 25-year-old man with PVNS of the hip. The physical examination was completely normal. Radiographs of the hip show erosions in the head and neck of the femur and the acetabulum. Magnetic resonance imaging showed a suspected malignant soft tissue mass involving the hip joint. The diagnosis of PVNS was confirmed by arthroscopy and biopsy, and the treatment of choice was an open synovectomy. One year after the operation the clinical examination was normal.