The Diagnostic and Etiologic Challenge of Myocarditis in Oncologic Patients: Acute Myocarditis During Induction Treatment with All-Trans Retinoic Acid

Myocarditis is an inflammatory disease of the myocardium characterized by myocardial infiltration with inflammatory cells and non-ischemic myocytic necrosis. Its diagnosis is based on clinical, electrocardiogram, laboratory and echocardiographic parameters and also cardiac magnetic resonance or endomyocardial biopsy when possible. It occurs primarily as a result of infections that include viruses, parasites, bacteria and fungi. Moreover, there are other causes of myocarditis such as autoimmune diseases and an exposure to toxic substances. Beta-blocker, angiotensin-converting enzyme and haemodynamic support is the first line therapy but the treatment must be adapted to the etiological diagnosis. In cancer patients, myocarditis can be caused by infections, autoimmune diseases, but also as an adverse effect of any therapy that modulates the immune system. Uncommon causes in oncologic patients should be considered. Myocarditis induced by all Transretionoic Acid has only been described in a few cases. We present a case of young women with a recent diagnosis of acute promyolicitic leukemia that develops myocarditis during induction therapy with all Transretinoic Acid in the setting of Retinoic Acid Syndrome. The clinical history, physical examination, electrocardiogram, laboratory results, transthoracic echocardiography, cardiac magnetic resonance and coronary angiography were integrated to reach a prompt diagnosis and etiological approach. A neurohormonal inhibitor treatment and corticosteroid therapy were rapidly initiated. Unlike other cases reported, the hematologic treatment was continued with at lower doses without withdrawing. This different approach could provide a new therapeutic management in similar situations.