Cerebral Aneurysms with Internal Carotid Artery Agenesis: A Unique Case Similar to Moyamoya Disease and Literature Review

A Rare and Unusual Cause of Ischemic Stroke to Be Aware of

Congenital absence of an internal carotid artery (ICA) is an extremely rare vascular anomaly. This case report presents an instance of right ICA agenesis to highlight the importance of early identification of this anomaly and its impact on disease presentation and complications. With transient ischemic attack (TIA), cerebrovascular accident (CVA), and cerebral aneurysms being among the chief presenting scenarios or course of the anomaly, it is important to have a high level of suspicion for these in patients with known ICA agenesis. Understanding the underlying development of this vasculature and its impact on cerebral circulation aids in identifying possible findings on imaging. This case report aims to delineate the pathophysiology of ICA agenesis, recognition of the vasculature that contributes to the anomaly, different presentations of the disease, complications, and obstacles in management.

Congenital unilateral absence of the internal carotid artery associated with aneurysms of different arteries: a review

There are four hundred and sixty- six cases of absent unilateral (398) and bilateral (68) internal carotid artery (ICA) published in online books, abstracts and original articles from 2020. to 2021. Of the 398 cases of absent unilateral ICA, 95 were associated with aneurysm. The analysis of these cases includes age, nationality and gender, location of aneurysm(s), description, and scheme of carotid-vertebrobasilar angioarchitecture mode in the brain base, as well as hypothesis on embryonic background of accompanying vascular variations and abnormalities. Calculated ratio between number of absent unilateral ICA cases and number of absent bilateral ICA cases is 5.8:1. The ratio between the total number of cases of absent unilateral ICA and those associated with aneurysms is 4.2:1. The association between the posterior communicating-middle cerebral anastomosis and intercavernous (trans-sellar or intercarotid) channel with absence of both anterior cerebral and anterior communicating arteries is common. More than half of the cases with aneurysms are located at the anterior segment vessels of the cerebral arterial circle. This review is based on the description and explanation of embryology and morphology of absent unilateral ICA with aneurysms, which would be significant contribution to published literature on this topic, especially due to the fact that nothing similar has been published since 1957.