Pembrolizumab-Induced Myocarditis and Pancreatitis in a Patient With Colon Cancer: A Case Report

We present a unique case of immune checkpoint inhibitor (ICI)-induced myocarditis and acute pancreatitis in a patient with metastatic colon cancer after seven cycles of pembrolizumab. A 43-year-old male with stage IV colon cancer on pembrolizumab presented with acute onset of heart failure with severely decreased ejection fraction (EF), conduction abnormalities, and normal coronary arteries on cardiac catheterization. He was started on high-dose steroids for grade 3 immune-related myocarditis. Four days later he presented with abdominal pain consistent with acute pancreatitis, likely related to the immune checkpoint inhibitors as well, Pembrolizumab was discontinued permanently. Pembrolizumab is currently used to treat many types of advanced cancers with promising results; thus, clinicians need to be aware of the multiple organs and systems that can be affected after using ICIs.