Internal Carotid Artery Absence: A Case Report and Literature Review

Internal carotid artery (ICA) absence is a rare congenital vascular anomaly. The resultant collateral blood supply has been categorized into six pathways, from type A to type F. The collateral blood supply often leads to asymptomatic presentations of ICA absence. However, ICA absence is closely linked to the development of aneurysms and their severe consequences, among other signs and symptoms. ICA absence is usually detected incidentally via computed tomography angiography (CTA) or digital subtraction angiography (DSA). There are currently no screening initiatives or treatments. In this case report, the authors will be discussing compiled evidence from various authors who have presented cases of incidentally found type A left ICA agenesis, and the surrounding literature.