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

Abstract IntroductionImmune checkpoint inhibitors (ICIs) prevent the immune escape of tumor cells, which is beneficial to immune cells such as T lymphocytes to continuously monitor and kill tumor cells, and ultimately play an effective role in anti-tumor. ICI-associated myocarditis (irMyositis) was rarely reported, but its onset appeared latent, rapidly developed, and lethal, which has gradually attracted the attention of clinicians. Case ReportWe reported cases of fulminant myocarditis in 3 patients with thymoma who were treated with pembrolizumab, one of the programmed cell death protein 1 inhibitors (PD-1 inhibitors).Management & OutcomeThe 3 patients were treated with methylprednisolone, immunoglobulin. Temporary pacemaker implantation was performed when case 1 suffered atrioventricular dissociation and ventricular escape. Cardioversion was performed in case 2 for the onset of ventricular tachycardia. In case 3, Extra-Corporeal Membrane Oxygenation was implemented. Unfortunately, the heart function did not improve and was succeeded by multiple organ failure in all 3 cases. The family withdrew treatment and led to lethal outcomes.DiscussionAlthough ICIs have achieved encouraging results in anti-tumor, their adverse reactions cannot be ignored. Patients with thymoma are more prone to autoimmune reactions which are needed more attention1. We reported cases of immunotherapy-associated myocarditis in patients with previous PM, showing the clinical and pathological features in the specific populations.