Immune checkpoint inhibitors (ICIs) can cause immune-related adverse events (irAEs) in various organs. Herein, we present a rare case involving a patient with immunotherapy-related gastritis who developed refractory vomiting and anorexia after treatment with nivolumab for cutaneous malignant melanoma. The patient was treated with oral corticosteroids, but the efficacy was limited. The symptoms improved markedly after treatment with infliximab.

With the increasing use of ICIs, the number of reports of gastritis due to irAEs has also increased. Health care providers treating malignancies should be aware of this side effect and know how to diagnose and treat it.