Immune Checkpoint Inhibitor Myocarditis on FDG PET/CT and Cardiac MR.
Shilpa Chandran, Lacey J McIntosh, David S Gerson et al.
✦ AI-curated · Sources linked
Case in brief
A 54-year-old man with stage 4 squamous cell carcinoma receiving pembrolizumab developed symptoms of heart failure. FDG PET/CT showed new cardiomegaly and intense myocardial uptake, while concurrent contrast-enhanced cardiac MRI demonstrated myocardial edema and gadolinium enhancement, consistent with myocarditis. After pembrolizumab was stopped and prednisolone initiated, follow-up FDG PET/CT showed resolution of the cardiomegaly and abnormal myocardial uptake, supporting an association with immune checkpoint inhibitor therapy.
What made this case unusual
The case illustrates concordant findings on FDG PET/CT and cardiac MRI, with subsequent resolution of the cardiac imaging abnormalities after immunotherapy cessation and prednisolone initiation.
Diagnostic / clinical pearl
In a patient receiving pembrolizumab who develops heart failure symptoms, myocardial FDG uptake and cardiac MRI evidence of edema and enhancement can support the diagnosis of myocarditis.
Why it matters
The report highlights the potential value of multimodality cardiac imaging in evaluating suspected immune checkpoint inhibitor-related myocarditis, a complication described as having disproportionately high mortality.