Persistent Primitive Hypoglossal Artery in a 55-Year-Old Woman with Recurrent Dizziness, Identified on Ultrasound and Computed Tomography Imaging

BACKGROUND Persistent primitive hypoglossal artery (PPHA) is a rare congenital condition due to an embryological vascular remnant consisting of an artery that usually originates at the C1-C2 vertebral level from the internal carotid artery (ICA), which bypasses the usual vertebral artery (VA) supply to the basilar artery (BA), and passes through the hypoglossal canal to the posterior fossa to connect to the vertebrobasilar system. This report describes the case of a 55-year-old woman presenting with dizziness due to a PPHA identified on ultrasound (US) and computed tomography (CT) angiography (CTA). CASE REPORT A 55-year-old woman presented with recurrent dizziness. First, carotid Doppler ultrasound (CDU) revealed the dilated left ICA with an increased peak systolic velocity (PSV) and an anomalous branch vessel at its distal end, plus hypoplastic bilateral extracranial VAs with high-resistance flow. Next, transcranial color-coded sonography (TCCS) showed no intracranial VA flow and reduced bilateral posterior cerebral arteries (PCAs) PSV upon left common carotid artery (CCA) compression. The combined findings of CDU and TCCS were suggestive of PPHA (eg, dilated left ICA with anomalous branch, hypoplastic bilateral VAs, reduced bilateral PCAs PSV upon left CCA compression). Subsequent CTA confirmed left-sided PPHA (ICA-C1 origin, hypoglossal canal passage, BA connection) and absent bilateral posterior communicating arteries. Finally, the patient received conservative medication. CONCLUSIONS This report presents a rare congenital vascular anomaly, PPHA, and aims to raise awareness of this condition, highlighting the approach to diagnosis using US and CT imaging.