Radiation-induced aneurysm and moyamoya vessels presenting with subarachnoid haemorrhage

A rare case of a ruptured internal carotid artery (ICA) aneurysm, with ICA stenosis and moyamoya vessels, was diagnosed in a young female patient afte r radiotherapy for optic glioma. Retrospective analysis revealed that an ex traordinarily high dose of radiation (110 Gy) had been delivered to the are a around the ICA in two therapeutic sessions. Clipping and wrapping of the aneurysm were performed and the patient made a good recovery. A review of t he literature suggested that rupture of radiation-induced aneurysms is a ra re event, but may be fatal. Considerable care must therefore be taken when delivering high-dose radiation to cerebral arteries. We suggest that the in cidence of radiation-induced moyamoya vessels is higher in younger patients .