Intracranial hemorrhage from an aneurysm encased in a pilocytic astrocytoma--case report and review of the literature.

The authors present an unusual complication of a recurrent chiasmal/hypothalamic pilocytic astrocytoma. From his second year of life onwards, the patient was repeatedly operated on and also underwent external radiation therapy (54 Gy total dose) 1 month after the first subtotal tumor resection. Nine years after irradiation, the patient was referred to our center with a sudden onset of severe headache, vomiting and neck stiffness. Computed tomography, magnetic resonance imaging, and cerebral angiography demonstrated an intratumoral, intraventricular, and subarachnoidal hemorrhage from an anterior communicating artery aneurysm encased in the pilocytic astrocytoma. The aneurysm was clipped and the patient recovered nicely from the hemorrhage. Three years later, the patient suddenly died of cardiac failure. Autopsy disclosed vessel wall changes compatible with radiation-induced vasculopathy. In light of this finding, the importance of radiation therapy and intracranial neoplasms for aneurysm formation is discussed.