Ischemic cerebellar infarction due to isolated anterior inferior cerebellar artery dissection mimicking peripheral otological symptoms: illustrative case

BACKGROUND: Ischemic stroke caused by anterior inferior cerebellar artery (AICA) dissection is rare, and cases limited to cerebellar infarction without brainstem involvement are particularly uncommon. AICA territory ischemia may initially present with audiovestibular symptoms, posing a diagnostic challenge by mimicking peripheral otological disorders. OBSERVATIONS: A 32-year-old woman presented with sudden sensorineural hearing loss, vertigo, and peripheral facial nerve palsy. A peripheral otological disorder was initially suspected; however, careful neurological examination revealed marked unsteadiness and torsional nystagmus, prompting brain MRI. Imaging demonstrated a focal cerebellar infarction without brainstem involvement. Follow-up CT angiography and digital subtraction angiography identified an isolated dissection of the proximal segment of the AICA. Despite improvement in facial nerve palsy and gait disturbance, the sensorineural hearing loss persisted. LESSONS: Peripheral otological symptoms do not exclude central vascular disease. Isolated AICA dissection may present without brainstem infarction and be occult on initial MRA; serial vascular imaging is mandatory when neurological findings are atypical. https://thejns.org/doi/10.3171/CASE2695.