Pituitary apoplexy associated with anterior communicating artery aneurysm and aberrant blood supply.

Pituitary apoplexy is an uncommon condition typically caused by acute, hemorrhagic expansion of the pituitary gland in patients with an adenoma that undergoes infarction. Although various risk factors have been described, the vascular events leading to apoplexy are not well understood. Disruption of microvascular blood flow is a well-known cause of morbidity from hemorrhage of an intracranial aneurysm, but pituitary apoplexy is rarely associated with aneurysmal subarachnoid hemorrhage. We report here a 46-year-old woman with pituitary apoplexy who developed subarachnoid hemorrhage from rupture of an anterior communicating artery aneurysm. Intraoperatively, she was found to have an unusual, large recurrent artery originating at the junction of the aneurysm and the A2 segment of the anterior cerebral artery that traveled to the suprasellar cistern and along the pituitary stalk. This recurrent hypophyseal artery established a direct vascular relationship between an intracerebral aneurysm and the pituitary gland.