Fatal Subarachnoid Hemorrhage from an Aneurysm of a Persistent Primitive Hypoglossal Artery

Background: Persistent carotid–basilar connections have a prevalence of 0.14%. Recognizing such persistent fetal anastomoses between the carotid and the vertebrobasilar circulation is of great importance because they are reportedly associated with an increased prevalence of intracranial aneurysms.
Methods: We report the case of a 15-year-old female patient who presented with a World Federation of Neurosurgical Societies grade 5 subarachnoid hemorrhage from an aneurysm at the junction of a persistent primitive hypoglossal artery and the posterior inferior cerebellar artery origin. Supratentorially, unfortunately, there was no parenchymal blush or cortical venous return. Eventually, a multidisciplinary decision was made to withdraw care.
Results: Fifty-seven cases were reported in the literature to date of persistent hypoglossal arteries, 16 of which presented with an associated aneurysm, 5 with an arteriovenous malformation, and 6 with a subarachnoid hemorrhage. Our case is the youngest patient reported so far. Hypoplasia or aplasia of the vertebral artery often were encountered (36 and 13 cases, respectively), as well as carotid artery stenosis (15 cases).
Conclusions: Although uncommon, it is important to recognize persistent carotid-basilar connections, since they have a considerable hemodynamic impact on the posterior cerebral circulation via the carotid system. A critical reduction in the carotid blood flow will, therefore, have ischemic consequences in the posterior cerebral territories. In addition, such connections might be associated with anomalies of the vessel wall and be predisposed to aneurysm formation. The endovascular neurointerventionalist, as well as the vascular and skull base neurosurgeon, need to be aware of their anatomy and variations.