A large vertebral artery fenestration involving the distal segments associated with bilateral duplication of the superior cerebellar artery: a case report.

Purpose: The aim of our study is to report a case of a large fenestrated vertebral artery (FVA) and bilateral duplication of the superior cerebellar artery (SCA) incidentally diagnosed using Computed Tomography Angiography (CTA) and Digital Subtraction Angiography (DSA).

Case presentation: A 63-year-old female patient presenting to the neurology clinic with complaints of dizziness and balance disorder. CTA and DSA revealed a large FVA involving the V3 and V4 segments. Additionally, we observed bilateral duplicated SCAs originating from the distal basilar artery.

Discussion: FVA is a rare anomaly resulting from fusion failure during the embryological period, with a reported incidence of 0.1%. FVA is often (70%) detected in the extracranial region, but it can also occur intracranially at a frequency of approximately 30%. Although various nomenclatures are used in the literature, we identified only two reports of a single fenestration encompassing the V3 and V4 segments, i.e., involving both the extracranial and intracranial regions. While duplication of the SCA is relatively common, bilateral duplication of SCA occurs at a rate of 0.9-5%.

Conclusion: This case report describes an unusual case of VA fenestration involving both extracranial and intracranial segments, along with bilateral duplication of the SCAs. While rare, these findings highlight the importance of recognizing such vascular anomalies, which could be relevant for planning surgical or endovascular procedures in the posterior circulation.