Reversible delayed radiation effect on the brain after radiotherapy of malignant astrocytoma.

A 14-year-old boy with a malignant astrocytoma in the third ventricle, who showed reversible delayed radiation effects on the brain, is presented. One and a half months after the completion of a course of radiation therapy, the patient gradually became drowsy complaining of headaches, general malaise and disturbance of gait. The symptoms and abnormalities in the CT scans were the most severe seven months after irradiation and then spontaneously subsided. CT scan could not differentiate it from a recurrence of the tumor when first seen, but was extremely useful in following these findings.