Absent Internal Carotid Artery With Intact Circle of Willis

James W Sonne,Helen Kaiser,Shanna Williams

doi:10.7759/cureus.17090

Abstract

The internal carotid arteries are one of the primary suppliers of the Circle of Willis and cerebral blood flow, but the rare case of agenesis of the internal carotid artery can impair the functional redundancies of cerebral blood supply.In this study, routine, medical education-focused cadaveric dissection of an 80-year-old male cadaver (cause of death was ventricular tachycardia) was performed.A case of agenesis of the left internal carotid artery and the carotid canal was identified. Upon investigation, we found that the compensatory pattern of irrigation in the Circle of Willis did not conform to previously described cases in the scientific literature. Further literature review suggested that such agenesis can be associated with a wide range of conditions from stroke, migraine, tinnitus, and Horner’s syndrome.Due to the altered blood flow pattern, we caution the reading physician regarding the potential for ischemia and iatrogenic damage, particularly of the pituitary gland and eye. We suggest the use of neuroangiographic imaging in cases of agenesis of an internal carotid artery.

Highlights

We suggest the use of neuroangiographic imaging in cases of agenesis of an internal carotid artery
The internal carotid arteries bifurcate from the common carotid arteries to traverse the carotid canals and eventually provide blood supply, along with the vertebral arteries, to the brain by way of the Circle of Willis [1]
We describe a case of left-sided agenesis of the internal carotid artery verified by absent ipsilateral carotid canal identified during routine cadaveric dissection for medical education

Summary

Introduction

The internal carotid arteries bifurcate from the common carotid arteries to traverse the carotid canals and eventually provide blood supply, along with the vertebral arteries, to the brain by way of the Circle of Willis [1]. We describe a case of left-sided agenesis of the internal carotid artery verified by absent ipsilateral carotid canal identified during routine cadaveric dissection for medical education. Hyperplasia of the vertebral, basilar, and contralateral internal carotid arteries was present; but no other morphological variations or remnant arteries were identified, and a complete Circle of Willis was present. Aside from marked hyperplasia of the vertebral, basilar, and right internal carotid artery, the Circle of Willis and related branches were present without notable variation (Figure 2). Additional types reported include persistent segmental or developmental arteries that often branch from the basilar artery to form an internal carotid artery within the cranium

Discussion

Conclusions

Disclosures