A1 Segment Unruptured Aneurysm of Persistent Primitive Olfactory Artery Coexisted with Accessory Middle Cerebral Artery

•A persistent primitive olfactory artery (PPOA) is a rare anomaly of anterior cerebral artery (ACA).•PPOA is associated with greater rates of aneurysm compared with vessels without structural anomalies.•An accessory MCA is a variant of the middle cerebral artery (MCA).•We experienced a rare case of coexistence of PPOA with an unruptured aneurysm and accessory MCA.•Three-dimensional computed tomographic angiography (3D-CTA) has an excellent picture of the spatial relationship of the surrounding bony and vascular structure. A persistent primitive olfactory artery (PPOA) is a rare anomaly of anterior cerebral artery (ACA), which generally arises from the internal carotid artery (ICA), runs along the olfactory tract, and makes a hairpin bend to supply the territory of the distal ACA. PPOA is also associated with cerebral aneurysms. An accessory MCA is a variant of the middle cerebral artery (MCA) that arises from either the proximal or distal portion of the A1 segment of the ACA, which runs parallel to the course of the MCA and supplies some of the MCA territory. We experienced a rare case of coexistence of PPOA with an unruptured aneurysm and accessory MCA. Three-dimensional computed tomographic angiography (3D-CTA) has an excellent picture of the spatial relationship of the surrounding bony and vascular structure.