To describe a case of right posterior cerebral artery (PCA) fenestration coexisting with bilateral superior cerebellar artery (SCA) duplication.

A 65-year-old woman with meningitis underwent cranial magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) using a 3-Tesla scanner. MRA was performed using a standard 3-dimensional time-of-flight technique.

MRI showed sulcal hyperintensity in the bilateral occipito-parietal regions on a fluid-attenuated inversion recovery (FLAIR) sequence, suggesting meningitis. MRA revealed no pathological lesions; however, fenestration of the right PCA at the P1-P2 junction and duplications of the bilateral SCAs were incidentally observed.

Using MRA, we diagnosed the first case of right PCA fenestration coexisting with bilateral SCA duplication. Although its clinical significance is limited, there may be a risk of misinterpretation or diagnostic confusion with pathological conditions such as aneurysms or dissections. Therefore, accurate identification of these arterial variations during MRA interpretation is essential. Careful observation of MRA images, along with the creation of partial volume-rendering images, is useful and important for diagnosing rare arterial variations.