Rupture of anterior communicating artery aneurysm during transsphenoidal surgery for pituitary adenoma

The case of a 55-year-old man with a nonfunctioning pituitary adenoma associated with an anterior communicating artery aneurysm that ruptured during transsphenoidal surgery is presented. This small aneurysm was not detected on bilateral angiography of the carotid artery before surgery. Computed tomography (CT) scans showed the pituitary adenoma extending to the suprasellar region and the sphenoid sinus. After intracapsular removal of the tumor, cerebrospinal fluid from an intraspinal catheter became bloody and CT scans disclosed massive subarachnoid hemorrhage. Repeated angiography revealed a tiny anterior communicating artery aneurysm, which was clipped on the 37th day after the operation. Risk factors in the procedure of transsphenoidal surgery, especially of a pituitary adenoma with suprasellar extension, are discussed.