title: Bilateral internal carotid absence: a case report of a rare congenital anomaly.
abstract: BACKGROUND
  Bilateral internal carotid artery agenesis (ICAA) is a rare developmental anomaly of unknown etiology that is often associated with disruption of adequate perfusion to the central nervous system. Nevertheless, some patients remain asymptomatic due to collateral circulation involving the communicating arteries of the Circle of Willis. Secondary to the hemodynamical stress through the collateral circulation, affected patients are at an increased risk of developing subarachnoid hemorrhage and intracranial aneurysms.
  
  
  RESULTS
  We report an unusual case of a 62-year-old man with bilateral ICAA who expired following two asystolic events during minor surgery.
  
  
  CONCLUSIONS
  This case emphasizes the plasticity of the cerebral collateral circulation during development, to the point of normal cerebral perfusion throughout life with no ischemic complications.
authors.affiliation: Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Luis F
authors.initials: LF
authors.lastname: Gonzalez-Cuyar
authors.forename: Dora
authors.initials: D
authors.lastname: Lam-Himlin
authors.forename: Fabio
authors.initials: F
authors.lastname: Tavora
authors.forename: Allen
authors.initials: A
authors.lastname: Burke
authors.forename: Rudy J
authors.initials: RJ
authors.lastname: Castellani
mesh_terms: D000015:Abnormalities, Multiple; D002340:Carotid Artery Diseases / Q000151:congenital* / Q000473:pathology; D002343:Carotid Artery, Internal / Q000002:abnormalities*; D003097:Collateral Circulation; D017809:Fatal Outcome; D006801:Humans; D007431:Intraoperative Complications / Q000401:mortality; D008297:Male; D008875:Middle Aged