LAUSR

PD-1 inhibitors contribute to immune response against malignancies. These drugs also result in serial side effects. Here the authors report a case of immune-related gastritis induced by PD-1 inhibitor. A female with metastatic lung cancer developed severe epigastric pain and acid reflux during treatment with toripalimab. She underwent several gastroscopies, which showed progressively worse gastritis. After discontinuing toripalimab, those symptoms were resolved. This rare report highlights gastritis associated with toripalimab, describes the symptoms and histology features and records the progression of this side effect and the corresponding treatment. Based on the improvement after toripalimab withdrawal, the authors believed that she had autoimmune gastritis caused by toripalimab. This case reminds us that correct diagnosis and proper management are critical to patients undergoing treatment with PD-1 inhibitors.