Multiple hereditary exostosis and Ollier's disease: how to tell the difference and next steps

Abstract

Both hereditary multiple exostosis (HME) and Ollier's disease (OD) present with focal bony expansions. However, they have distinct aetiologies and prognosis. HME causes multiple osteochondromas that are exophytic growths outside of the bone, typically around the metaphysis and diaphysis and affecting particularly the fibular and ulna more than the tibia and radius. In contrast, OD causes multiple enchondromas that are expansile bony masses in the diaphysis of the limbs and hand bones. Both conditions tend to spare the skull, are asymmetric and can lead to significant deformity. OD can lead to shortened deformed bones with gross local swelling. HME can cause a Madelung deformity of the wrist and short stature. Both present during childhood. The major difference is in the risk of malignancy. The risk of skeletal malignancy is much higher in OD, and patients with OD also have increased risk of other cancers such as of the ovary and liver. In the absence of targeted medical therapies, surgical treatment is focused on removing lesions that, if left, have a high potential for functional loss along with robust surveillance for both local complications and malignant transformation.