title: Agenesis of internal carotid artery in a child with ipsilateral Horner's syndrome.
abstract: Horner's syndrome is characterized by a classic triad of ipsilateral pupillary miosis, partial eyelid ptosis, and facial anhydrosis. This case study reports a 7-year-old boy with right miosis, mild blepharoptosis, and iris hypopigmentation detected in a routine pediatric follow-up without ipsilateral facial anhydrosis, flushing, or pain. There was no history of birth trauma and test with cocaine provoked no response of the right pupil, suggesting right Horner's syndrome. Mediastinal tumor was ruled out and brain magnetic resonance imaging incidentally showed absence of flow in the right internal carotid artery. Subsequent magnetic resonance angiography demonstrated agenesis of the right internal carotid artery without other vascular-associated malformations. The final diagnosis was right, congenital Horner's syndrome due to ipsilateral internal carotid agenesis. We describe in detail the radiological findings and pathophysiological mechanisms of this unusual association.
authors.affiliation: Department of Child Neurology, Hospital Sant Joan de Déu for Children, University of Barcelona, Barcelona, Spain. cfons@hsjdbcn.org
authors.forename: Carmen
authors.initials: C
authors.lastname: Fons
authors.forename: Monica
authors.initials: M
authors.lastname: Vasconcelos
authors.forename: Mariona
authors.initials: M
authors.lastname: Vidal
authors.forename: Ramón
authors.initials: R
authors.lastname: Puy
authors.forename: Antonio
authors.initials: A
authors.lastname: Capdevila
authors.forename: Laia
authors.initials: L
authors.lastname: Sanchez
authors.forename: Jaime
authors.initials: J
authors.lastname: Campistol
mesh_terms: D002340:Carotid Artery Diseases / Q000151:congenital*; D002343:Carotid Artery, Internal / Q000002:abnormalities* / Q000473:pathology; D007839:Functional Laterality / Q000502:physiology*; D006732:Horner Syndrome / Q000151:congenital* / Q000175:diagnosis; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult