Clinical significance of unexplained abnormal focal FDG uptake in the abdomen during whole-body PET

OBJECTIVE. FDG PET is frequently used as part of the diagnostic workup in cancer patients. Visualization of radiotracer-avid foci suggests the presence of malignant disease. Unexplained focal FDG accumulation in the abdomen is sometimes noted, but the clinical significance of this finding is unknown. Therefore, we followed cases with unexplained focal abdominal FDG uptake found incidentally on whole-body scans to define the cause and clinical significance of this finding. CONCLUSION. Unexplained focal abdominal FDG uptake is an unusual finding with causes that include malignant and benign processes. Among the 14 cases with definitive diagnoses, seven were adenomas, which is a premalignant condition, and five (35.7%) were malignant. Therefore, although rare, unexplained focal abdominal FDG uptake should not be ignored and further diagnostic workup is warranted.