Abstract：
Cancer immunotherapy using immune checkpoint inhibitors can cause immune reactions at various sites as a side effect called immune-related adverse events (irAEs). The gastrointestinal tract is susceptible to irAEs, however, the degree and presentation vary considerably from case to case. A 76-year-old woman was diagnosed with anal mucosal melanoma. She underwent radical surgery and received postoperative adjuvant therapy. However, because new metastases were also found in bilateral inguinal lymph nodes, immunotherapy with nivolumab was performed. Approximately 10 months after the initiation of nivolumab administration, she presented with epigastric discomfort and nausea, and her laboratory data showed severe eosinophilia (1938/mm3). Computed tomography demonstrated a diffuse thickening of the gastric wall. Esophagogastroduodenoscopy and endoscopic ultrasonography showed mucosal thickening due to edema, and histologic examination revealed severe invasion of eosinophils in the lamina propria. Subsequently, she was diagnosed with eosinophilic gastritis due to irAEs induced by nivolumab. Oral administration of prednisolone rapidly normalized her endoscopic and histologic findings, dramatically reducing her symptoms. This is a very rare and important case report of nivolumab-induced severe eosinophilic gastritis. Although gastric lesions as IrAEs is rare, it is necessary to differentiate eosinophilic gastritis if unexplained nausea occurred during the administration of immune checkpoint inhibitors.
摘要：
使用免疫检查点抑制剂的癌症免疫疗法可以在多个部位引起免疫反应，作为称为免疫相关不良事件（irAEs）的副作用。胃肠道容易发生不良反应,然而,程度和陈述因案例而异。一名76岁的妇女被诊断出患有肛门粘膜黑色素瘤。她接受了根治性手术并接受了术后辅助治疗。然而,因为在双侧腹股沟淋巴结中也发现了新的转移，进行了nivolumab免疫治疗.开始nivolumab给药后约10个月，她出现了上腹部不适和恶心,她的实验室数据显示严重的嗜酸性粒细胞增多（1938/mm3）。计算机断层扫描显示胃壁弥漫性增厚。食管胃十二指肠镜和内镜超声检查显示由于水肿引起的粘膜增厚，组织学检查显示嗜酸性粒细胞严重侵入固有层。随后，由于纳武单抗诱导的irAE,她被诊断为嗜酸性粒细胞性胃炎.口服泼尼松龙迅速使她的内窥镜和组织学检查结果恢复正常。大大减轻了她的症状.这是nivolumab引起的严重嗜酸性粒细胞性胃炎的非常罕见且重要的病例报告。尽管作为IrAE的胃部病变很少见，如果在免疫检查点抑制剂给药过程中出现原因不明的恶心,则有必要区分嗜酸性粒细胞性胃炎.
