Congenital absence of the internal carotid artery is a rare occurrence. Even more infrequent are cases where the patient has a bilateral absence of the internal carotid arteries. Reported is a case of a 52-year-old woman who presented with optic nerve neuropathy, and was incidentally discovered to have a congenital bilateral absence of her internal carotid arteries. During computed tomography angiography imaging looking for cerebral venous thrombosis, related to her preexisting condition of bilateral elevated optic discs and residual left optic neuropathy, the findings were made. The absence of the arteries is not always recognizably symptomatic, with most findings being incidental through imaging studies only. This is because collateral flow allows for sufficient cerebral circulation. However, this condition puts such patients at higher risk for conditions such as aneurysms and subsequently strokes where the collateral flow exists.
Chaudhry, S. R., Barreto, S., & Ezhapilli, S. R. (2018). Bilateral congenital absence of the internal carotid arteries: a case report. Radiology Case Reports, 13(6), 1146–1149. https://doi.org/10.1016/j.radcr.2018.08.006