Acute myocarditis with transient myocardial thickening in two oncologic patients treated with anti‐GD2 immunotherapy

Immunotherapy has considerably improved clinical outcomes in different types of cancers but has also been associated with the development of myocarditis, especially with that mediated by immune checkpoint inhibitors. To the best of our knowledge, these are the first cases of myocarditis after anti‐GD2 immunotherapy reported to date. We present two cases of paediatric patients who, after anti‐GD2 infusion, presented severe myocarditis with myocardial hypertrophy detected on echocardiography and confirmed with cardiac magnetic resonance imaging. An increase in myocardial T1 and extracellular volume of up to 30% was observed with heterogeneous intramyocardial late enhancement. Myocarditis after anti‐GD2 immunotherapy may be more common than appreciated, occurs early after starting treatment, has a malignant course, and responds to higher steroid doses.