Primary synovial chondromatosis

Abstract

Background: Primary synovial chondromatosis (SC) is a rare disease of the synovial membrane of unclear etiology. A brief review of the current state of knowledge on this disease is presented. Methods: Reviews and recent case reports on SC were systematically evaluated and compared with data from our own patients. Results: Based on recent genomic data, SC is classified as a benign neoplasm. Mutations in the fibronectin 1 gene (FN1) and/or the activin A type II receptor gene (ACVR2A) are present in 60% of patients. Diagnostic evidence is provided by magnetic resonance imaging (MRI) and usually arthroscopic biopsy of the synovium. We demonstrate in one case that the cartilage aggregates of SC are not always radiologically shadow forming. Differential diagnoses include monarthritides of other causes, other joint and muscle diseases with mineralization and other diseases originating from the synovial membrane. Malignant transformation occurs in 2–4%. Therapeutically, the arthroscopic approach has gained acceptance in recent years, which is adapted to the extent of the disease. Conclusion: Genomic studies and recent case series and case reports shed new light on SC. Therapeutically, recent work has predominantly used an arthroscopic approach.