Unanticipated Biatrial 18F-Fluorodeoxyglucose (18F-FDG) Uptake in Diffuse Large B-cell Lymphoma Surveillance PET/CT.

Cardiac lymphomas are rare manifestations of diffuse large B-cell lymphoma (DLBCL), occurring either primarily or secondarily. Imaging modalities such as magnetic resonance/computed tomography (MR/CT) and fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) are pivotal for accurate detection and staging. However, cardiac FDG uptake during oncological PET/CT scans lacks specificity, necessitating further investigation into abnormal patterns, particularly in atrial FDG uptake, which may indicate underlying cardiac arrhythmias. A significant proportion of atrial fibrillation (AF) patients exhibit heightened FDG uptake in the atrium, correlating with an increased stroke risk. We present an asymptomatic 81-year-old female with DLBCL, hypertension, and AF, incidentally found to have abnormal biatrial FDG uptake on surveillance PET/CT. This case underscores the importance of comprehensive cardiology evaluation in asymptomatic oncology patients to manage potential cardiac complications effectively. Advanced imaging techniques and integrated care strategies are crucial for optimizing outcomes in cardiac lymphoma patients.