Malignant cerebellar astrocytoma developing 15 years after radiation therapy for a medulloblastoma

A case of malignant cerebellar astrocytoma occurring 15 years after the radiation therapy for a medulloblastoma is reported. The tumor developed at the same site of irradiation after a sufficient latent period and was completely different from medulloblastoma in its histology. This tumor fulfilled the criteria of radiation-induced neoplasm. Only seven similar cases have been reported up to the present. Whole neuraxis irradiation following a gross total resection is a standard treatment for medulloblastoma, but the possibility of the development of radiation-induced tumors must be borne in mind for a long time after the radiation therapy for medulloblastoma.