PD-1 inhibitor‐induced cytomegalovirus esophagitis in a patient with metastatic urothelial carcinoma: A case report

Immune checkpoint inhibitors (ICIs), such as Pembrolizumab, have revolutionized cancer treatment. However, they pose challenges, specifically in the form of immune-related adverse events (irAEs). Although cases of gastrointestinal irAEs have been well-documented, the occurrence of cytomegalovirus (CMV) esophagitis months after immunotherapy discontinuation, has not been well reported. We report a case of immune-related CMV esophagitis three months after discontinuing pembrolizumab therapy, which had been administered for metastatic urothelial cancer. IrAE and their timing remain a challenge in patients receiving ICI therapy. CMV esophagitis is a rare irAE associated with ICIs and further investigation is needed to better develop effective treatment and prevention strategies. • Immune checkpoint inhibitors pose multiple challenges in regards to adverse events • Immune-related CMV esophagitis due to PDL-1 inhibitor has rarely been report • PDL-1 can induce an inflammatory state, thereby provoking an exaggerated response to CMV reactivation