title: Congenital agenesis of internal carotid artery with ipsilateral Horner presenting as focal neurological symptoms.
abstract: Internal carotid artery (ICA) agenesis is a rare developmental anomaly and is most frequently asymptomatic, but it may also present as cerebrovascular accidents. The association with Horner's syndrome is exceptional. We present three cases of agenesis of ICA associated with Horner's syndrome and hypochromia iridum presenting as focal neurological symptoms. A system of collaterals develops as a consequence of agenesis of the ICA, making the majority of cases asymptomatic. Three types of collateral circulations have been described. These collaterals increase the risk of aneurysm formation and the occurrence of life-threatening subarachnoid hemorrhages. The association of congenital Horner's syndrome and hypochromia iridum without anhidrosis is highly suggestive of sympathetic pathway injury early in life. Such signs should prompt further diagnostic evaluation to demonstrate the presence of the agenesis of the carotid canal. Early diagnosis is essential to rule out potentially life-threatening associated vascular anomalies.
authors.affiliation: Service de Neurologie, Hôpital Henri Mondor, APHP, Faculté de Médecine, Université Paris XII, Créteil, France.
authors.forename: Wassim
authors.initials: W
authors.lastname: Farhat
authors.forename: Rechdi
authors.initials: R
authors.lastname: Ahdab
authors.forename: Hassan
authors.initials: H
authors.lastname: Hosseini
mesh_terms: D000328:Adult; D002343:Carotid Artery, Internal / Q000002:abnormalities* / Q000503:physiopathology; D002533:Cerebral Angiography / Q000379:methods; D002560:Cerebrovascular Circulation; D003097:Collateral Circulation; D005260:Female; D006732:Horner Syndrome / Q000150:complications* / Q000503:physiopathology; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D012039:Regional Blood Flow; D020521:Stroke / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D014057:Tomography, X-Ray Computed; D054079:Vascular Malformations / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D055815:Young Adult