Unilateral Agenesis of Internal Carotid Artery with Intercavernous Anastomosis: A Rare Case Report

Abstract

Unilateral agenesis of internal carotid artery (ICA) with intercavernous anastomosis is a rare congenital anomaly. We present a case of a 25-year-old female with 2-month history of holocranial headache. Neurological examination was unremarkable. Magnetic resonance imaging (MRI) with magnetic resonance angiography (MRA) showed absence of left ICA with an abnormal intercavernous vessel in the sella. Computed tomography (CT) showed absence of the left carotid canal. Doppler ultrasonography (USG) showed high resistance flow in the left common carotid artery (CCA). Since no hemorrhage or aneurysm was seen, patient was managed conservatively and is on regular follow-up. Based on our knowledge, this is the first case to demonstrate the features of unilateral agenesis of ICA with intercavernous anastomosis in X-ray, Doppler USG, CT, and MRI scans of the brain.

Agenesia de artéria carótida interna

“…A slight predominance among men and a preference for the left, at a ratio of 3:1, have been reported. [4][5][6] According to Lie, the term agenesis describes a complete absence of an organ or structure, whereas aplasia is caused by a lapse in development of an organ -the precursor of which is present -and hypoplasia is the term attributed to incomplete development. It is believed that unilateral agenesis is caused by mechanical or hemodynamic intrauterine stress.…”

“…The cause of bilateral agenesis is still unknown. 5,7 Development of the internal carotid initiates at a point at which the embryo has a 4-5 mm crown-rump length (CRL: the distance from the top of the cranium to the mid-point between the apexes of the buttocks) and is completed during the 6th week of gestation (CRL =10-14 mm). The circle of Willis forms at the 7-24 mm stage (gestational age of around 7 weeks).…”

“…7 Since Lie published these descriptions in 1968, other authors have reported presence of a persistent trigeminal artery surrounded by collaterals supplying flow in a patient with unilateral agenesis of the internal carotid. 5 It is important to identify compensatory anastomoses -such as intercavernous anastomoses -to avoid devastating perioperative complications in procedures such as trans-sphenoid access to the pituitary.…”

Internal carotid artery agenesis with stenosed intercavernous anastomosis: a case report

“…The third type which is similar to our patient is extremely rare, the affected ICA is absent from the origin, and an intercavernous anastomotic vessel communicates bilateral ICAs. Only 19 cases have been reported till now [ 2 - 3 ] .…”

“…The golden criteria to diagnose this disease may be cerebral angiography, while MRA and MRI examination are also helpful in showing the location of anastomotic artery and other tissues around. Computed tomography (CT) is very useful in illustrating the absence of the carotid canal [ 3 ] . In our case, we can also show the absence of the carotid canal in MRI images.…”