Currently there are no clearly-defined systemic or local therapies for the bone disease, and results of the use of conventional surgical treatment of sites of impending fracture have been universally disappointing. In this study, we will treat osteolytic lesions in the long bones of the upper and lower extremities, the sites of potential fracture, with a novel surgical approach. This will involve 1) the removal of abnormal tissue through percutaneous aspiration, and 2) the use of skeletal precursor cells taken from the unaffected sites, mixed with a bone grafting substitute, and injected into the affected sites to bring about an improvement in local bone quality and overall patient function.