De Novo Crohn's Disease 3 Years Following Immune Checkpoint Inhibitor Therapy

Presented is a 76-year-old man with metastatic melanoma that was successfully treated with pembrolizumab, an immune checkpoint inhibitor (ICI). He underwent 20 months of ICI treatment without dose limiting side effects. Nearly 18 months after ICI discontinuation, the patient developed intermittent epigastric pain and diarrhea. Owing to mild symptoms, he was not immediately evaluated. Three years after ICI cessation, he was diagnosed with stricturing, jejunal Crohn's disease. He was treated with vedolizumab and displayed clinical and radiographic response to treatment. This case serves as an example of potential gastrointestinal-related, long-term autoimmune implications of ICI therapy, even in patients without acute side effects.