Abstract
BACKGROUND: Immune checkpoint inhibitors (ICIs) have led to improved outcomes for many cancer types. However, their use can also precipitate immune-related adverse events (irAEs) that can affect any organ system. While irAEs are often mild, they rarely affect multiple organ systems concurrently and can be fatal. CASE: We report a fatal case of myasthenia gravis, myositis, and cardiotoxicity overlap syndrome precipitated by the ICI pembrolizumab along with a brief review of available literature. CONCLUSION: Early recognition of high grade irAEs and prompt intervention is essential. Despite the poor prognosis of these overlap syndromes, current recommendations offer little guidance for severe cases and warrant a call for increased awareness and expansion of available therapeutics.