Congenital agenesis of internal carotid artery with ipsilateral Horner presenting as focal neurological symptoms

Abstract

Internal carotid artery (ICA) agenesis is a rare developmental anomaly and is most frequently asymptomatic, but it may also present as cerebrovascular accidents. The association with Horner’s syndrome is exceptional. We present three cases of agenesis of ICA associated with Horner’s syndrome and hypochromia iridum presenting as focal neurological symptoms. A system of collaterals develops as a consequence of agenesis of the ICA, making the majority of cases asymptomatic. Three types of collateral circulations have been described. These collaterals increase the risk of aneurysm formation and the occurrence of life-threatening subarachnoid hemorrhages. The association of congenital Horner’s syndrome and hypochromia iridum without anhidrosis is highly suggestive of sympathetic pathway injury early in life. Such signs should prompt further diagnostic evaluation to demonstrate the presence of the agenesis of the carotid canal. Early diagnosis is essential to rule out potentially life-threatening associated vascular anomalies.

An anatomical investigation of the carotid canal

“…In the computed tomographic study conducted by Motoshima et al [17], patients with Moyamoya disease presented with distinctively narrowed CCs than those of the control/asymptomatic group. As a result, the diameter of the CC is ultimately dependent on the embryological development of the ICA [10,23]. During weeks 3 and 4 of embryonic development, the ICA arises from the arteries of the third aortic arch and the distal segment of the dorsal aorta [10].…”

“…As a result, the diameter of the CC is ultimately dependent on the embryological development of the ICA [10,23]. During weeks 3 and 4 of embryonic development, the ICA arises from the arteries of the third aortic arch and the distal segment of the dorsal aorta [10]. Since the base of the skull only develops during week 5, the prior development of the internal carotid artery will determine the morphometric and morphological presence of the CC [10].…”

“…During weeks 3 and 4 of embryonic development, the ICA arises from the arteries of the third aortic arch and the distal segment of the dorsal aorta [10]. Since the base of the skull only develops during week 5, the prior development of the internal carotid artery will determine the morphometric and morphological presence of the CC [10]. Despite the rare occurrence of ICA hypoplasia or agenesis, it may often result in the formation of collateral circulations and subsequent intracranial haemorrhage [10].…”

“…Since the base of the skull only develops during week 5, the prior development of the internal carotid artery will determine the morphometric and morphological presence of the CC [10]. Despite the rare occurrence of ICA hypoplasia or agenesis, it may often result in the formation of collateral circulations and subsequent intracranial haemorrhage [10]. In the present study the mean distance of 27.94 mm recorded between the external margins of the CC and the summit of mastoid process was comparatively less than that reported by Cicekcibasi et al [8] (31.08 mm).…”

Congenital Horner Syndrome with Heterochromia Iridis Associated with Ipsilateral Internal Carotid Artery Hypoplasia

“…Associations with corpus callosum agenesis, meningocele, neurofibromatosis, Klippel-Feil syndrome, 22q11.2 deletion syndrome, coarctation of the aorta, and other cardiac anomalies have been described. 5 …”