Intracranial hemorrhage from undetected aneurysmal rupture complicating transphenoidal pituitary adenoma resection.

We report a case of a 39-year-old man who presented with a nonfunctioning pituitary macroadenoma which extended into the suprasellar region. He underwent a transcranial resection of the tumor followed eight months later by transsphenoidal surgery for the residual tumor. Postoperatively he developed massive subarachnoid and intraventricular hemorrhage. A cerebral angiogram revealed a leaking anterior communicating artery aneurysm which was not seen on the computed tomography angiography and magnetic resonance angiography before the surgery. Complications of transsphenoidal surgery, particularly vascular hemorrhagic complications, and risk of rupture of undetected aneurysms are discussed.