Agenesis of the internal carotid artery (ICA) is defined as the failure in the development of this structure and the complete absence of the carotid canal. It is considered a rare anomaly, with an incidence lower than 0.01% , usually presented as unilateral involvement, predominantly on the left side (3/1) and exceptionally presented bilaterally, there are currently only 26 documented cases of bilateral agenesis worldwide in literature . Inmost casespatientsremainasymptomatic forlongperiods of time due to the development of compensatory collateral circulation through the circle of Willis or persistent embryonic arteries, which can be sufficient to maintain cerebral perfusion, without ruling out possible limitations and complications of this adaptation of the vascular system . The first documented case was described by Tode in 1787 after performing a necropsy, and the first diagnosis “in vivo” was conducted by Verbiest in 1954 through cerebral arteriography .
The diagnosis is primarily made incidentally during a radiological examination by other causes,for example, after a cerebrovascular disease impact factor event such as a subarachnoid hemorrhage subsequent to the rupture of an aneurisma