Nonbifurcating Carotid Artery: A Case Report with a Review of Embryogenesis

Abstract

Patient: Male, 66Final Diagnosis: Nonbifurcating carotid arterySymptoms: No symptomsMedication: —Clinical Procedure: —Specialty: NeurologyObjective:Congenital defects/diseasesBackground:Vascular anomalies of the carotid vessels can be attributed to false embryogenesis. A rare variant called a nonbifurcating carotid artery (NBCA) exists, where typical carotid bifurcation is not recognizable with its typical branches of the external carotid artery (ECA) and internal carotid artery (ICA). This paper describes a case of this anomaly and reviews the embryogenesis of the carotid arteries for explanation.Case Report:A 66-year-old man received a routine health examination at our hospital. Initial carotid ultrasound indicated an absence of bifurcation in the right cervical carotid artery, and magnetic resonance imaging of the brain indicated an absence of the proximal cervical segment of the right ICA, with a remnant arterial stump at the expected bifurcation level. No evidence of the carotid bulb was identified. The common carotid artery seemed to continue cranially in the trunk of the ECA, where it exhibited extracranial branches. After distributing these branches, the carotid artery coursed medially at the C2 level, where it ascended into the carotid canal to become the petrosal segment of the ICA. This carotid anomaly was labelled an NBCA. No aberrant intracranial arteries were derived from the NBCA in this case.Conclusions:In this case, the arterial stump was considered a remnant from agenesis of the right ICA. We assumed that the NBCA most likely developed because of false regression of the third embryogenic aortic arch with persistence of the second aortic arch.

A nonbifurcating cervical carotid artery with a remnant of the proximal internal carotid artery that mimicked an aneurysm on magnetic resonance angiography

“…According to a review of the literature, only three cases of nonbifurcating cervical carotid arteries have ICA remnants [1,2,7]. We herein report the fourth case of a nonbifurcating cervical carotid artery with an ICA remnant that mimicked an aneurysm on MR angiography.…”

“…In this variation, the ECA has no proximal main trunk. However, it is believed that this variation is formed by segmental agenesis of the most proximal ICA [1,10]. This variation was initially named a nonbifurcating cervical carotid artery in 1990 by Morimoto et al [4].…”

Anomalous external carotid-internal carotid artery anastomosis diagnosed by computed tomography angiography: a case report

“…Embryologically, the ICA develops from the third aortic arch and the dorsal aortic roots cranial to the third aortic arch during early gestation [4 , 5] . In contrast, the ECA develops from 2 connected arteries [4 , 6] .…”

“…In contrast, the ECA develops from 2 connected arteries [4 , 6] . The ventral aortic roots cranial to the third aortic arch become the ventral pharyngeal artery and the ventral second aortic arch finally regresses [5] . The dorsal second aortic arch becomes the hyoid artery.…”

“…The dorsal second aortic arch becomes the hyoid artery. The stapedial artery, the main branch of the hyoid artery, connects the ventral pharyngeal artery and separates from the hyoid artery at the 24 mm embryonic stage [5 , 7] . The typical ECA then derives from the combination of the ventral pharyngeal artery and stapedial artery [5] .…”