Late-Onset Fulminant Myocarditis With Immune Checkpoint Inhibitor Nivolumab.

A 60-year-old man was diagnosed with melanoma. After receiving 13 infusions of nivolumab, he had fulminant myocarditis. The myocardial biopsy specimen revealed extensive lymphocytic infiltration, interstitial edema, and myocardial necrosis, with predominant CD4+, CD8+, CD20-, and programmed death-1- markers. Programmed death-1 ligand 1 (PD-L1) was predominantly expressed on the surface of the damaged myocardium. Although it is reported that myocarditis induced by the human anti-programmed death-1 inhibitor nivolumab therapy rarely occurred at > 2 months use in clinical trials, this case showed that even if at a late phase, long-term use of immune checkpoint inhibitors might to lead immune-related adverse events including myocarditis.