Agenesis of right internal carotid artery with associated anterior communicating segment aneurysm and azygos A2 segment: First description of a rare anatomic variant

• Published in: Interdisciplinary neurosurgery : Advanced techniques and case management 2021-09, Vol.25, p.101264, Article 101264
• Main Authors: Gómez, Diego F., Jaramillo-Velásquez, Daniel, Molina, Óscar I., Hakim, Fernando
• Format: Article
• Language: English
• Subjects: ACA aneurysm; Azygos; Collateral circulation; ICA dysgenesis
• ISSN: 2214-7519; 2214-7519
• DOI: 10.1016/j.inat.2021.101264

•ICA dysgenesis is a rare finding that usually remains asymptomatic due to collateral circulation.•Collateral circulation is under significant hemodynamic stress and there is increased incidence of intracranial aneurysms.•In some instances, predisposing congenital factors may also be responsible for aneurysm and vascular malformations in these patients.•Unruptured intracranial aneurysms in patients with ICA dysgenesis might need early therapeutic interventions.•There is not enough evidence to state aneurysms in these patients need a different approach than unruptured aneurysms in other clinical context. ICA dysgenesis is a rare finding and whose aetiology is not yet fully elucidated. Collateral circulation is very common; hence it is usually an incidental finding. Collateral circulation is under significant hemodynamic stress and therefore intracranial aneurysms are frequent in cases of ICA dysgenesis. We report the case of a 57-year old female who presented with headache and right ICA agenesis with associated anterior communicating segment aneurysm and azygos (unpaired) A2 segment. To the best of our knowledge this rare anatomic variant has not been reported. These patients should undergo thorough investigation for intracranial aneurysms and should receive prompt treatment. To date there is not enough information as to indicate specific treatment for aneurysms in these patients.