Primary Intra-articular and Extra-articular Synovial Chondromatosis in a Child: A Rare Cause of Shoulder Pain in Children.

Synovial chondromatosis is a rare condition with chondroid metaplasia of the synovial membrane and multinodular proliferation of the synovial membrane of the joints, tendons and bursae without any certain etiology. The disease generally presents in monoarticular form; and the most commonly involved joint is the knee. It commonly occurs in third and fifth decades of life. Synovial chondromatosis of the shoulder in children is extremely rare; and up to now, only two cases have been reported in the literature. Herein, we report synovial chondromatosis of the shoulder joint in a child with both intraarticular and extraarticular involvement. To the best of the authors' knowledge, this is the first case in the literature with both intra- and extra-articular involvement of synovial chondromatosis of the shoulder joint in children. Key Words: Synovial chondromatosis, Metaplasia, Children.