The progression of an infundibulum to aneurysm formation and rupture: case report and literature review.

Abstract

Infundibula (IFs) are funnel-shaped symmetrical enlargements that occur at the origins of cerebral arteries and are apparent on 7 to 25% of otherwise normal angiograms. They are frequently considered as normal anatomic variants of no pathogenic significance. We report the case of a ruptured posterior communicating artery aneurysm that had developed at the site of a previously known IF in a 49-year-old hypertensive woman. She had a poor conscious level at admission, with widespread subarachnoid hemorrhage and obstructive hydrocephalus. The patient was immediately ventilated, and an external ventricular drain was inserted. The aneurysm was successfully clipped; however, secondary hemorrhage occurred both before and during craniotomy. She developed marked hypernatremia and subsequently died. This is the 11th case of IF-to-aneurysm progression reported. It suggests that in certain cases, serial investigations may be indicated with IFs to detect aneurysm formation and preempt rupture.