Overlapping Hepatotoxicity and Colitis Associated with Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that widely used for the management of many solid-organ and hematologic cancers. These agents work by inhibition cytotoxic T-lymphocyte–associated antigen-4 (CTLA-4), programmed cell death-1 (PD-1), PD ligand 1 (PD-L1). Hyperactivation immune system results in ICI-associated adverse events. Simultaneous hepatotoxicity colitis associated with ICIs is rare potentially overlooked, as clinical symptoms often nonspecific. A 73-year-old man metastatic squamous carcinoma presented six weeks after starting pembrolizumab abdominal discomfort diarrhea. Pembrolizumab therapy was held, supportive antidiarrheals provided partial relief. After initial workup, hepatitis (ICIH) ICI-related (ICIC) were diagnosed. Colitis resolution required corticosteroids. This case illustrates importance high index suspensions gastrointestinal hepatic events ICIs, which may be overlooked result severe complications. While isolated ICIH ICIC well known events, overlapping rare. Prompt recognition, cessation inciting agent, initiation early essential. Treatment require corticosteroids or mycophenolate mofetil.