Osteochondroma after total body irradiation: an age-related complication

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).

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.

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.

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.