Primary intra-articular synovial chondromatosis represents an uncommon condition involving mainly the large joints predominantly of middle-aged adults. We herein document the first case of synovial chondromatosis affecting the acromio-clavicular joint of a 10-year-old girl, characterized by a solitary huge intra-articular osteochondromatous body (giant synovial chondromatosis) that had caused dislocation and deformation of the lateral portion of the clavicle. Successful surgical treatment consisted of removal of the osteochondral body and replacement of the clavicle by fixation with a K-wire.
