Intracranial aneurysm formation following radiotherapy.

Two patients sustained a subarachnoid haemorrhage secondary to radiation-induced vasculopathy and associated aneurysm. A 65-year-old woman was treated by radiotherapy for a stereotactically biopsied left parieto-temporal astrocytoma. Three-and-a-half years later, she suffered a subarachnoid haemorrhage secondary to a giant aneurysm arising from the middle cerebral artery bifurcation. A 44-year-old man sustained a subarachnoid haemorrhage 21 years after receiving whole brain irradiation for a large left parietal angioma. Angiography following his subarachnoid haemorrhage revealed a distal right middle cerebral artery aneurysm that was not visible on earlier angiograms. Both patients underwent craniotomy for their aneurysms with good postoperative recoveries.