Radiation-induced bone sarcoma following total body irradiation: role of additional radiation on localized areas

A 44-year-old patient who had had acute monoblastic leukemia developed an o steosarcoma of the pelvic bones 5 years after an allogeneic bone marrow tra nsplant from his HLA-identical sister. He had additionally received superfi cial cutaneous radiation of the legs and pelvis, over the 3 weeks prior to total body irradiation (TBI), because of cutaneous leukemic lesions. The tu mor was a fibrohistiocytomatous osteogenic sarcoma. The first lesion was in the right ilium, and a second lesion appeared 18 months later, symmetrical ly on the left ilium. Despite treatment, the patient died from metastases. At the time of diagnosis of radiation-induced sarcoma, the patient was free of leukemia and had several risk factors already reported to favor the dev elopment of solid tumors in stem cell recipients. These include acute leuke mia, TBI and graft-versus-host disease. As he developed symmetrical lesions of the pelvic bone, and because of the histology of the radiation-induced tumor, we assumed that the additional radiation of the skin prior to TBI ma y have contributed to the pathogenesis of this malignant fibrous histiocyto ma. Therefore, the risk/benefit ratio should be carefully considered in unu sual indications. These patients should benefit from a close follow-up of t he superimposed areas.