Fulminant Myocarditis Complicated with Immune Checkpoint Inhibitor in Patients with Thymoma: Report of Three Cases

: Immune checkpoint inhibitors (ICIs) prevent the immune escape of tumor cells, which helps immune cells such as T lymphocytes to continuously monitor and kill tumor cells, and play powerful anti-tumor role. Immune checkpoint inhibitor-associated myocarditis has been rarely reported; however, its latent, rapidly developed, and lethal onset has gradually attracted the attention of clinicians. This study aimed to report cases of fulminant myocarditis in three patients with thymoma who were treated with pembrolizumab, one of the programmed cell death protein 1 inhibitors (PD-1 inhibitors).