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

Wei Qin, 1,* Xiao Wang, 1,* Jing Yang, 2 Wenli Hu 1 1Department of Neurology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, People’s Republic of China; 2Department of Hyperbaric Oxygen, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, People’s Republic of China*These authors contributed equally to this workCorrespondence: Jing YangDepartment of Hyperbaric Oxygen, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, People’s Republic of ChinaTel +86 1085232005Email jyangu@hotmail.comWenli HuDepartment of Neurology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, People’s Republic of ChinaTel +86 1085231376Email stroke2019@126.comAbstract: Anti-γ-aminobutyric acid B receptor (anti-GABABR) encephalitis is a rare type of autoimmune encephalitis (AE). Although it responds well to immunomodulating therapy and has favorable prognosis, anti-GABABR AE has often been misdiagnosed as infectious encephalitis. Herein, we present a case of a 59-year-old female with anti-GABABR 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.Keywords: autoimmune encephalitis, anti-GABAB receptor, small cell lung cancer