Abnormal F-18 fluorodeoxyglucose (FDG) accumulation patterns in the lung in patients with cancer having whole-body F-18 FDG-PET/CT scanning for restaging purposes are usually associated with primary lung tumors or lung metastases. Other diagnoses include postobstructive pneumonia and/or atelectasis, granulomatous lung disease, or occult lung infarction. In the latter, enhanced F-18 FDG accumulation topographically matches otherwise proven areas of pulmonary embolism. We document focally enhanced F-18 FDG uptake in the thrombus in the right pulmonary artery in a patient with silent pulmonary embolism. We hypothesize that enhanced F-18 FDG accumulation is attributed to the inflammatory reaction and scavenger cell activity associated with the pathophysiological cascade in pulmonary embolism.