title: An Unruptured Aneurysm Coexisting with an Infundibular Dilatation: A Case Report.
abstract: BACKGROUND
  Infundibular dilatation (ID) is a funnel-shaped enlargement of the origin of cerebral arteries. The coexistence of an aneurysm and ID is relatively rare. Patients with IDs are rarely followed up. However, some IDs have been reported to develop into aneurysms with subsequent rupture. Here we report on a case of an aneurysm that coexisted with ID of the posterior communicating artery.
  
  
  METHODS
  A 51-year-old woman underwent magnetic resonance imaging (MRI) to check for aneurysms and other problems. MRI revealed an unruptured aneurysm of the right internal carotid artery, for which the patient was admitted to our hospital. Three-dimensional computed tomographic angiography revealed an aneurysm, which protruded outward, and ID of the posterior communicating artery, which protruded inward. A right pterional craniotomy was performed with aneurysm clipping. The postoperative course was uneventful. In this report, we demonstrate operative views of the aneurysm and ID with the use of neuroendoscopy.
  
  
  CONCLUSIONS
  ID can develop into a true arterial aneurysm and potentially rupture. Therefore, we need to observe the patients with IDs carefully, particularly in young women.
authors.affiliation: Department of Neurological Surgery, Nippon Medical School.
authors.forename: Takao
authors.initials: T
authors.lastname: Kitamura
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Murai
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Shirokane
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Matano
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kitamura
authors.forename: Akio
authors.initials: A
authors.lastname: Morita
mesh_terms: D000783:Aneurysm / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging*; D003399:Craniotomy; D004108:Dilatation, Pathologic / Q000150:complications; D004724:Endoscopy; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D020769:Posterior Cerebral Artery / Q000000981:diagnostic imaging* / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D014656:Vascular Surgical Procedures / Q000379:methods