Osteochondroma after total body irradiation: an age-related complication.

BACKGROUND: The discovery of a mass lesion in a long-term cancer survivor causes significant anxiety. The causes of such a mass include benign osteochondroma, which has been reported following focal irradiation and total body irradiation (TBI). PROCEDURE: To establish the incidence of osteochondromas following TBI, the medical records of all children treated at the Sydney Children's Hospital who received TBI as part of the conditioning prior to bone-marrow transplantation between 1978 and 1997 were reviewed.
RESULTS: Five of 58 children who received TBI as part of the conditioning therapy for bone-marrow transplantation and who have been followed for at least 30 months post-irradiation, developed osteochondromas. All five of the patients had been under 5 years of age when they received TBI (mean 2.4 years), giving an incidence of osteochondroma of 24% in those who received TBI in the first 5 years of life. No osteochondromas have been diagnosed among the 37 patients who were aged between 5 years and 15 years at the time of receiving TBI. The mean latent time to diagnosis of osteochondroma was 4.6 years (range 2.5-9 years). Two patients developed multiple osteochondromas. Two patients required resection of their osteochondromas because of symptoms. Neither showed malignant degeneration.
CONCLUSIONS: Younger patients are at increased risk of osteochondroma following TBI. Review of the available literature suggests a low malignant potential of radiation-induced osteochondromas. Knowledge about the behaviour of post-irradiation osteochondromas will help clinicians manage patients appropriately. Copyright 2003 Wiley-Liss, Inc.