Megavoltage therapy in patients with aneurysmal bone cysts.

Three adolescent patients with similar destructive lesions involving the pelvis were found to have unresectable aneurysmal bone cysts. All 3 patients appear to have permanent control and good function from 2 to 7 years after megavoltage irradiation with 4,000 rads. No complications or late sequelae have occurred, and follow-up radiographs demonstrate reconstitution and calcification of the affected bone. A slightly lower dose may be just as effective in controlling such lesions.