Radiation-induced edema after radiosurgery for pontine arteriovenous malformation. A case report and detection by magnetic resonance imaging.

A 29-year-old woman, who had undergone stereotactic radiosurgery for a pontine arteriovenous malformation, experienced sudden onset of facial nerve palsy with trigeminal nerve disturbance 19 months after irradiation. Magnetic resonance imaging revealed significant radiation-induced edema surrounding the nidus. Angiography demonstrated total obliteration of the arteriovenous malformation 24 months after irradiation. Further magnetic resonance imaging studies, performed 28 months after treatment, showed that, despite the persistence of symptoms, the radiation-induced edema had subsided.