Intracranial aneurysm arising from infundibular dilation

Infundibular dilations (IDs) are funnel-shaped enlargements in the origin of intracranial arteries. Usually, IDs occur at the junction between posterior communicating artery (PcomA) and internal carotid artery (ICA). Progression from an ID of the PcomA to aneurysms has been described, but is unclear whether an ID is a preaneurysmal state or a normal anatomical variant. The authors describe a 55-year-old female patient presenting multiple intracranial aneurysms with a small one arising from an ID at the level of posterior communicating segment of ICA. To the best of our knowledge, after a criterious search in the English literature, it is the first description of such unusual combination. The preoperative neurosurgical planning is discussed as well as the importance of intraoperative findings to the best management of this unusual situation.