Radiation-induced tumors of the central nervous system occurring in childhood and adolescence - Four unusual lesions in three patients and a review of the literature

The authors report four very rare radiation-associated tumors (or radiation -induced tumors; RITs) of the central nervous system (CNS) and review the l iterature on this topic. The purpose of this study was to determine the pos sible relationship between the harmful effects of radiation therapy, the sh ortest and the longest interval between the time of irradiation and the occ urrence of the secondary tumor, and possible predisposing factors. The tumo rigenic effects of therapeutic irradiation of the CNS have been mentioned i n the literature, but the authors' literature search did not disclose eithe r many reports of cases such as their own or a satisfactory and concise dis cussion on the different aspects of the late and catastrophic complications of this method of adjunct therapy to the CNS. Four rare cases of RIT in th ree patients are presented: a unique case of intradural meningioma of the c ervical spine, which was irradiated successfully only for the patient to pr esent with a new high-grade cerebral astrocytoma 4 years later, a paraventr icular cavernoma and a fronto-temporo-orbital chondrosarcoma. These second RITs became symptomatic in the 17th, 16th and 15th years of life, respectiv ely, in these young patients. The primary lesions were ependymomas, two in the IV ventricle and one in the left hemisphere. The time intervals between radiation and secondary tumor presentation were 14 and 18 years, 9 years a nd 28 months, in the order in which these patients presented. All the patie nts survived the second operation except the one with chondrosarcoma, who d ied in spite of repeated surgical interventions and adjunct therapies. It i s concluded that the development of secondary RITs does not necessarily req uire a very long time interval; that although sarcomas ale the most common RITs of the CNS in childhood and adolescence, benign and other rare and cur able lesions may also occur in the field or vicinity of the field of radiat ion; and that in view of the possibility of occurrence of different types o f RITs after varying time intervals in a single patient, whole-life follow- up of similar patients is mandatory.