Congenital absence of internal carotid artery with intercavernous anastomosis: Case report and systematic review of the literature

Abstract

<jats:p> The absence of an internal carotid artery is a rare congenital anomaly. In the absence of the internal carotid artery, collateral circulations develop through the circle of Willis, persistent embryonic arteries or transcranial collaterals of the external carotid artery. Six pathways of collateral circulation have been described. Intercavernous anastomosis is between cavernous segments of the bilateral internal carotid arteries and is rarely seen. Patients with an absence of the internal carotid artery can be completely asymptomatic. However, these patients can present with subarachnoid hemorrhage or stroke accompanying cerebral aneurysm or abnormal collateral. We combined our case with 33 previous publications to form a retrospective series including 35 cases of unilateral internal carotid artery agenesis with intercavernous anastomosis. </jats:p>

Unilateral agenesis of internal carotid artery associated with superior cerebellar artery aneurysm and anomalous origin of ophthalmic artery arising from the ipsilateral posterior communicating artery

“…The present case also presented with agenesis of the ICA on the left side. As agenesis of the ICA usually leads to sufficient collateral circulation to the affected side of the brain parenchyma, most cases are asymptomatic and are therefore frequently identified incidentally [1 , 4] . However, some patients can also present with subarachnoid hemorrhage from aneurysm rupture or symptoms related to associated vascular insufficiency due to changes in the collateral flow [3 , 5] .…”

“…Embryologically, the primitive ICA originates from the fetal third aortic arches and cranial extensions of the embryonic dorsal aorta around the 3-mm fetal stage [3 , 6] . ICA development is completed at 6 gestational weeks [1] . Although the exact mechanism of unilateral agenesis of the ICA has not been established, postulated causes of this developmental anomaly have been thought to present the sequela from an insult to the developing embryo [2] .…”

“…In the congenital absence of ICA, collateral circulation develops through the circle of Willis, persistent embryonic arteries, or transcranial collaterals of the external carotid artery [1] . Lie described 6 pathways of collateral circulation in association with the absence of the ICA [8] .…”

“…Other less common collateral flows are through persistent embryonic arteries or transcranial collaterals of the external carotid artery system [1 , 5] . It is associated with the embryonic period in which there is a disruption of ICA development [1] . The circle of Willis forms during the 7-24 mm stage of the embryonic period [1] .…”

“…Agenesis, aplasia, or hypoplasia of the internal carotid artery (ICA) are rare congenital vascular anomalies, seen in less than 0.01% of the population [1 , 2] . Most cases of ICA agenesis are clinically silent due to well-developed sufficient collateral circulations; therefore, it is usually detected incidentally on head and neck imaging [3] .…”