A Rare Case of Synovial Chondromatosis of Knee with both Intra-articular and Extra-articular Involvement: A Case Report

Introduction: Synovial chondromatosis (SC) is a relatively rare benign disorder characterized by developing many nodules composed of cartilage within the synovial cavities of joints. It impacts several joints, with the knee joint being the most often affected. Extra-articular involvement, such as bursae or tendon sheaths, is rare. Furthermore, the coexistence of intra- and extra-articular SC is an infrequent condition. Hence, we present a rare case of SC with intra- and extra-articular involvement. Case Presentation: The patient, a 38-year-old woman, reported experiencing progressive right knee discomfort for 2 months. In addition, a growing mass was observed on the medial aspect of the right knee that was noticeable for the past 2 months. MRI examination revealed the presence of both intra-articular and extra-articular lesions. A two-step surgical procedure, including arthroscopy synovectomy involving the debridement of the lesions and removal of the extra-articular mass through an open incision, was performed. Histopathological analysis confirmed SC. At the 1-year follow-up, the patient reported complete relief of discomfort in the right knee. Conclusion: The coexistence of extra-articular and intra-articular SC is an exceedingly rare condition. Surgical removal of the loose bodies and a synovectomy performed as thoroughly as possible constitute the mainstay of treatment in managing SC. Keywords: Synovial chondromatosis, extra-articular, intra-articular, joint loose bodies, knee