Elevated Troponin T in Immune-Checkpoint Inhibitor Myositis: A Case of Mistaken Myocarditis.

A patient with metastatic renal cell carcinoma on axitinib and pembrolizumab had elevated high-sensitivity cardiac troponin T and normal high-sensitivity cardiac troponin I with unremarkable cardiac investigations. A noncardiac cause (myositis) was the likely cause for cardiac troponin T elevation. Cardiac troponin I may be a more appropriate marker to support a myocarditis diagnosis with concurrent myositis.