Multiple Hereditary Exostoses. Clinical problems and therapeutic options

Multiple Hereditary Exostoses (MHE) is a rare autosomal dominant disorder characterized by the presence of multiple osteochondromas. Patients often present with growth disturbances and angular deformities of the long bones, and a limited range of motion of the joints. In adults, the risk of malignant transformation of osteochondroma into chondrosarcoma exists, with an estimated incidence of 3–6%. In addition to the physical deformities, pain is a significant problem for patients with MHE and the disease has a profound negative influence on activities of daily living, occupation and school performance.In the treatment of patients with MHE, knowledge about the various disorders encountered and the natural course of the disease, as well as appropriate timing of interventions are essential. Surgical treatment may not only include the excision of osteochondromas but also limb reconstruction procedures to correct deformities. During childhood, however, this may be limited to procedures such as hemiepiphysiodesis for valgus deformity of the knee and ankle to prevent more extensive surgery at older age. Furthermore, early recognition of malignant degeneration of osteochondroma and the immediate treatment of chondrosarcoma are of the utmost importance for patient survival. Therefore, periodic screening in children as well as adults is highly recommended.