Total body irradiation-induced osteochondromata.

Nine patients developed osteochondromata, a mean of 6 years after total body irradiation (TBI) given before bone marrow transplantation for childhood leukaemia. This represents 23% of patients receiving TBI during the period from 1981 to 1989 surviving > or =5 years after bone marrow transplantation. The patients were followed up for a mean of 12.5 years from diagnosis of leukaemia and a mean of 2.5 years from diagnosis of osteochondromata. No osteochondroma, including three lesions removed surgically, showed evidence of malignant change. Six patients received growth hormone for irradiation-induced growth hormone deficiency, but this did not appear to influence the natural history of the osteochondromata. Radiation-induced osteochondromata (RIO) are often multiple and are indistinguishable from the more common idiopathic type. The incidence of RIO after TBI was higher than that reported after local irradiation.