Case report 714. Postirradiation osteosarcoma after radiation of metastatic skeletal lesion.

Two cases of postirradiation osteosarcoma are presented--one in a 76-year-old woman with breast carcinoma and subsequent osteosarcoma after radiation therapy for a metastatic lesion in the right tibia, and the other in a 16-year-old girl with hepatocellular carcinoma metastatic to the left tibia and osteosarcoma after radiation therapy to that bone. Microscopically, both cases were high-grade spindle cell lesions with osteoid production. Both patients fared poorly. This is a rare complication of radiation therapy.