Abstract
Posterior inferior cerebellar artery (PICA) aneurysm is relatively rare. We report on a 74-year-old woman presenting with dizziness and right-side tilted gait caused by a right-side distal PICA aneurysm, which mimicked a right lateral medullary infarction. A neurological examination showed right-side limb ataxia and left-beating torsional nystagmus, similar to a right lateral medullary infarction. Magnetic resonance imaging revealed a distal PICA aneurysm in the right-side middle cerebellar peduncle region.