High-dose interleukin 2-induced myocarditis: can myocardial damage reversibility be assessed by cardiac MRI?

High-dose interleukin 2 (HD-IL2) is one of the therapeutic options for patients with metastatic renal cell carcinoma. In well-selected patients with favorable clinical and pathologic features, it offers impressive response and potential long-term remission. It also has a place for treatment for metastatic malignant melanoma and in adoptive cell therapy. However, it is known for its intensive course and toxicities. Myocarditis is one of the known complications of this treatment and can pose a diagnostic challenge to treating oncologists because of its nonspecific and similar presentation to acute coronary syndrome (ACS). We report 3 short cases of HD-IL2-related myocarditis, which were either missed or misdiagnosed as ACS using conventional assessment but subsequently accurately diagnosed by cardiac magnetic resonant imaging (CMR). We discussed the clinical presentation of these cases and demonstrated the diagnostic advantage of CMR compared with standard investigations including its superior capability to assess myocardial reversibility, which has important short-term and long-term implications. The use of CMR also avoided unnecessary invasive intervention such as coronary angiogram in all 3 patients. These example cases call for effort to conduct prospective research to assess and confirm the utility of CMR, thus informing a more effective management pathway for immune-related myocarditis in HD-IL2 and other cancer immunotherapy.