Multiple Anterior and Posterior Circulation Intracranial Fenestrations presenting With Aneurysmal Subarachnoid Hemorrhage.

: Intracranial artery fenestrations are very rare, however, when found, there is a high association with cerebral aneurysms. : This report describes a patient with multiple anterior and posterior circulation intracranial artery fenestrations and an anterior communicating artery aneurysm presenting with a thunderclap headache found to have a subarachnoid hemorrhage (SAH). The patient was treated with open surgery via clipping after a diagnostic angiography and did very well. : There is an association between cerebral fenestrations and aneurysms, but it has not been studied in a prospective manner. This case is unusual in that the patient had both anterior and posterior circulation fenestrations, which is uncommon. Clinicians should have a high index of suspicion in patients being evaluated for SAH who have a cerebral artery fenestration with no aneurysm found.