Internal carotid artery (ICA) anatomical variations are relatively rare occurrences during diagnostic imaging procedures. Their presence can have important prognostic consequences in the evaluation of vascular neurological diseases. It is therefore important to have a good knowledge about these variations, in order to avoid unwarranted medical interventions. We present the case of a patient harboring a right ICA fenestration in the cervical segment, misdiagnosed as a dissection on computed tomography angiography, admitted in the Department of Neurology and treated accordingly. The possible pathological and embryological origins of arterial fenestrations are discussed, and a brief review of the literature related to ICA fenestrations is presented.