Paraneoplastic anti-N-methyl-D-aspartate receptor encephalitis associated with small cell lung cancer: A dramatic recovery after chemotherapy

Tumor management is the cornerstone of treatment for anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis that is refractory to immunosuppressive therapy. However, little is known about the effectiveness of chemotherapy for malignant tumors in patients with severe neurological conditions. We herein report a 66-year-old male who fell into a coma caused by anti-NMDAR encephalitis associated with small cell lung cancer (SCLC). Corticosteroid pulse therapy failed to improve his neurological condition, but a chemotherapy regimen containing atezolizumab led to rapid improvement in his condition. This case suggests that chemotherapy, including atezolizumab, may provide a rapid therapeutic benefit for anti-NMDAR encephalitis associated with SCLC.