Multimodal Imaging Demonstrated a Case of Buccal Cancer Cardiac Metastases Treated With Immune Checkpoint Inhibitor Therapy

A 35-year-old man with recurrent oral cancer underwent restaging FDG PET/CT imaging, which revealed neck lymph node metastasis and multiple distant metastases, including involvement of the right atrium, right ventricle, and pericardium. Doppler echocardiography and cardiac MRI confirmed the cardiac metastases while demonstrating preserved left ventricular systolic function. Follow-up FDG PET/CT imaging at 3 and 6 months after immune checkpoint inhibitor therapy, initiated due to high PD-L1 expression in the primary tumor, showed complete remission.