A case of acute lymphocytic gastritis related to treatment with pembrolizumab for metastatic urothelial carcinoma.

Introduction: Immune checkpoint inhibitors such as programmed cell death/-ligand 1 inhibitor and cytotoxic T-lymphocyte-associated antigen-4 inhibitors have been widely used for various advanced malignancies. The mechanism of action for these inhibitors is the improvement of antitumor immunity via T-cell modulation. On the contrary, immune-related adverse events such as autoimmune colitis might arise in association with T-cell activation.