Immune-related giant cell myocarditis after immune checkpoint inhibitor therapy in a patient with urothelial carcinoma and myasthenia gravis

Abstract

Immune-related adverse events (irAEs) have drawn global attention after the extended use of immune checkpoint inhibitors (ICIs) in the past decade. These inflammatory side effects hinder cancer treatment and potentially have a negative impact on the prognosis. Myocarditis is an infrequent but often life-threatening irAE, and the pathogenesis remains unclear owing to its rarity and fulminant nature. We present a case of immune-related giant cell myocarditis after pembrolizumab treatment for unresectable urothelial carcinoma of the bladder in a patient with underlying invasive thymoma and myasthenia gravis. This unusual presentation highlights the complexity of immune crosstalk in patients with autoimmune diseases who receive ICI therapy. Further, investigations and individualized treatment for this population are warranted to minimize toxicity.