Coexistence of Anti-SOX1 and Anti-GABAB Receptor Antibodies with Autoimmune Encephalitis in Small Cell Lung Cancer: A Case Report.

Anti-γ-aminobutyric acid B receptor (anti-GABA_BR) encephalitis is a rare type of autoimmune encephalitis (AE). Although it responds well to immunomodulating therapy and has favorable prognosis, anti-GABA_BR AE has often been misdiagnosed as infectious encephalitis. Herein, we present a case of a 59-year-old female with anti-GABA_BR AE associated with small cell lung cancer (SCLC) that was once misdiagnosed as infectious encephalitis. Our findings increase the awareness that patients presenting with a clinical trial of cognitive impairment, seizures and SCLC may harbor AE. Our case also highlights the importance of anti-SOX1 antibody in the detection of SCLC.