Using their own personal series of 19 cases of leprosy complicated by massive osteolysis (AO), along with a comparison of these cases with data from previously published reports, the authors review the principal clinical and radiological findings of these manifestations which are not observed except in cases of leprosy where neuropathy is present, even though other factors (perforating plantar ulcers, poor hygiene, traumatisms) may play a contributing role independent of possible interference from non specific osteoarthritis or Hansen's bacilla, itself. After reviewing other causes of massive osteolysis and discussing the pathogeny of these manifestations during leprosy, the authors refer to the various therapies which can prevent or stabilize osteolysis or aid the patient to better tolerate its manifestations.