Case Report: Atypical anti-KLHL11 antibody encephalitis: recurrent staring spells, serial negative MRI findings, and a tripartite diagnostic journey.

Anti-Kelch-like protein 11 (KLHL11) antibody encephalitis is a rare autoimmune neurological disorder, typically characterized by cerebellar syndrome and brainstem involvement, with magnetic resonance imaging (MRI) lesions predominantly localized to the brainstem and cerebellum consistent with rhombencephalitis. Epilepsy as the primary clinical presentation of this disease has been rarely reported. Herein, we describe a case of anti-KLHL11 encephalitis in which the patient presented with recurrent staring spells as the chief complaint, accompanied by transient mild cerebella signs. Brain imaging and routine cerebrospinal fluid (CSF) tests were unremarkable during the first two admissions; only generalized slow waves were detected on electroencephalogram (EEG) in the second admission. At the third admission, brain MRI revealed T2 hyperintensities in the left frontal and parietal lobes and CSF examination showed elevated protein levels; subsequent antibody testing confirmed anti-KLHL11-IgG positivity, thereby establishing a definitive diagnosis. The patient had negative results on tumor screening and exhibited a favorable response to therapy with corticosteroids, intravenous immunoglobulin and efgartigimod. This case highlights the diverse clinical manifestations and staged progression of anti-KLHL11 encephalitis, which warrants full recognition in clinical practice. For patients suspected of autoimmune encephalitis, dynamic re-examination of cranial imaging and CSF, as well as timely KLHL11-IgG testing, are critical for early diagnosis and prompt treatment, thereby improving prognosis. Additionally, this case expands the current understanding of anti-KLHL11 antibody encephalitis regarding its clinical presentations, imaging features, and therapeutic responsiveness.