Concomitance of Persistent Primitive Olfactory Artery and Basilar Artery Fenestration.

The cerebral arterial circle exhibits substantial morphological variability, occasionally encompassing rare congenital vascular variants. We report a unique case of a 64-year-old woman in whom computed tomography angiography (CTA) revealed the coexistence of a persistent primitive olfactory artery (PPOA) and basilar artery (BA) fenestration. The PPOA originated from the left anterior cerebral artery (ACA) and coursed anteroinferior toward the cribriform plate, where it formed a characteristic hairpin turn before resuming the typical A2 trajectory. Concurrently, a BA fenestration was identified, with the right anteroinferior cerebellar artery arising from the right limb of the fenestrated segment. The simultaneous occurrence of these two vascular morphological variants is a unique phenomenon. The recognition of such variations is critical, as both may alter cerebral hemodynamics, predispose to aneurysm formation, and complicate surgical or endovascular interventions. The awareness of these vascular variants is essential for accurate diagnosis and surgical planning. CTA and magnetic resonance angiography (MRA) remain reliable, non-invasive imaging modalities for the identification and characterization of these conditions.