Fibrous metaphyseal defects

: Fibrous metaphyseal defects (FMD) are tumor-like bone lesions according to the WHO classification of 1994. They are found in children and adolescents. FMD occur at characteristic points in the circumference of long bones. Depending on age, the distance to the epiphyseal line varies. The longitudinal axis of FMDs in the direction of the epiphysis meets a tendon or ligamentous structure inserting at the growth plate line. This tendon, which inserts at the perichondrium of the epiphyseal cartilage and the surrounding periosteum, seems to have a causal relationship in the pathogenesis of FMDs. In 152 specimens obtained from the autopsy of long tubular bones with open epiphyseal growth plates, the tendons and ligamentous structures inserting into the perichondrium of the epiphyseal plate cartilage were examined. Within the site of two tendon-inserting areas (Ranvier's node), the pathomorphological picture revealed that the normal medullary tissue is displaced by fibroblastic tissue. In addition to the etiopathogenesis of FMD's the radiological, clinical and histological features and the prognosis are discussed.