Fig. 1.

Patient enrollment. Between April 2018 and February 2021, 528 patients received immune checkpoint inhibitor (ICI), 30 of them presented with diarrhea, bloody stools, or abdominal pain during ICI therapy or after discontinuation of ICI. Of these 30 patients, 18 patients underwent colonoscopy (CS) and ultrasonography (US) for the suspicion of immune-mediated colitis (IMC). Those whose CS or US showed no inflammatory findings as well as those who were diagnosed with other diseases such as infectious enteritis based on tissue biopsy and stool culture were excluded from the study. A total of 14 patients were enrolled who were diagnosed with IMC based on CS findings.