Cerebellar ataxia as the initial symptom with lesions involving the cerebellum in patient with anti-NMDAR encephalitis: A rare case report and literature review.

Cerebellar ataxia is an atypical presentation of anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis. In patients with anti-NMDAR encephalitis, cerebellar ataxia often develops simultaneously or sequentially with clinical features of demyelinating disorders, paraneoplastic neurologic syndromes, despite unremarkable brain magnetic resonance imagerying (MRI) findings. Herein, we report a patient with anti-NMDAR encephalitis who developed dizziness and gait ataxia as the initial symptoms, simultaneously showing MRI hyperintensities involving the cerebellum, even before manifesting behavioral and cognitive symptoms. We excluded the co-occurrence of other autoantibodies using cell- and tissue-based assays to establish a confirmed diagnosis of definite anti-NMDAR encephalitis.