Pigmented Villonodular Synovitis of the Knee Joint in a 10-Year-Old Patient Treated With an All-Arthroscopic Synovectomy: A Case Report

Pigmented villonodular synovitis (PVNS) is a relatively rare, benign lesion characterized by exuberant proliferation of the synovial tissue that most commonly affects the knee and hip joint. Magnetic resonance imaging (MRI) is the imaging modality of choice for the diagnosis of PVNS. The disease is confirmed histologically by examination of the synovial tissue removed. The mainstay of treatment is synovectomy, performed in an open, arthroscopic, or combined fashion. Although postoperative adjuvant external beam radiotherapy can improve the local recurrence rate, the course of the disease is not always uneventful. We present a rare case of a 10-year-old boy presented to our orthopaedic department with a four-month history of intermittent right knee pain and swelling. MRI revealed joint effusion and extensive nodular synovial proliferation suggestive of PVNS. An arthroscopic synovectomy was performed and histological examination confirmed the diagnosis. The postoperative course was uneventful. Clinical suspicion of PVNS is essential in children with chronic knee pain and swelling. Arthroscopic synovectomy is an effective and reliable treatment option.