Background <p>Congenital cerebrovascular anomalies, such as middle cerebral artery hypoplasia and vertebral artery with an aortic arch origin, are well-documented in isolation but exceedingly rare in combination. Their coexistence may critically disrupt cerebral hemodynamics, yet clinical implications remain poorly characterized, highlighting the novelty of this case.</p> Case presentation <p>A 68-year-old male presented with chronic refractory dizziness that worsened with positional changes and showed no improvement after standard management for benign paroxysmal positional vertigo. Comprehensive neurovascular imaging, including multimodal angiography, revealed two coexisting anomalies—left middle cerebral artery hypoplasia with duplicate trunks and distal tortuosity, along with an aberrant left vertebral artery originating directly from the aortic arch, which exhibited extracranial tortuosity with impaired flow and was identified as non-dominant. The hemodynamic vulnerability was further compounded by a right fetal-type posterior cerebral artery and a patent left posterior communicating artery, with an anterior communicating artery that was not visualized. The patient received antiplatelet and statin therapy, but the symptoms persisted, underscoring the refractory nature of the condition.</p> Conclusions <p>This unique constellation of anomalies may create a fragile hemodynamic state, which likely contributed to the patient’s refractory symptoms. This case underscores the importance of comprehensive vascular evaluation, including assessment of the circle of Willis, in patients with unexplained neurological symptoms. Advanced angiographic assessment is crucial for accurate diagnosis and to avoid misinterpreting congenital variants as acquired pathology.</p>