Massive osteolysis (phantom bone, spontaneous absorption of bone, or disappearing bone disease) is a bizarre entity characterized pathologically by angiomatosis. Its etiology is unknown, the clinical progression and prognosis are unpredictable, and treatment is uncertain. Absorption, initially localized to one bone, often extends to involve those adjacent to such a degree that clinically the ultimate impression can hardly be considered anything less than “malignant.” The associated angiomas, however, are histologically benign and no pathologically malignant tissue is present. Deformity and disability may be extensive; widespread involvement of ribs and vertebrae may cause death. Since the first case of spontaneous absorption of bone recorded by Jackson (7, 22) in 1838, at least 38 additional cases have been documented. Gorham and Stout (9, 10), in a review of 24 of these, emphasized the hemangiomatous nature of the bone in the zones of osteolysis. Three years later, Johnson and McClure (17) reviewed 8 add...