A Case of Esophago-gastric Junctional Cancer who Developed Autoimmune Encephalitis after Administration of Nivolumab

Abstract

The patient was a 56-year-old man who had been treated with S-1 + cisplatin therapy, SOX therapy and ramucirumab + paclitaxel therapy for unresectable esophago-gastric junctional cancer (cT4N1M0). However, his pathologic condition took downhill course, and these therapies were replaced with nivolumab (240 mg) therapy. From the second day after completion of the 2^nd course of the nivolumab therapy, the patient developed high fever with shaking chills and was brought into our hospital by ambulance. He manifested convulsions lasting for several minutes in his extremities and lips. Imaging examinations revealed no newly appeared abnormal findings. No antipyretic effect was gained even after initiation of antimicrobial therapy. On a cerebrospinal fluid examination, the protein level and cell count were as high as 138 mg/dl and 16/μL, respectively ; PCR test for herpes simplex virus was negative and cytomegalovirus IgM, negative. Administration of steroids resulted in significant symptomatic remission. Accordingly, his illness was diagnosed as autoimmune encephalitis. Although immune checkpoint inhibitors rarely provoke central nervous impairment, there are some cases in which the patients follow a fatal course. We must consider therapeutic intervention mainly with steroids in an early phase when encephalitis is suspected.