The clinical value of incidental 18F-fluorodeoxyglucose-avid foci detected on positron emission tomography/computed tomography.

Objective: This study was performed to show the malignant potential and clinical value of incidental focal 18F-fluorodeoxyglucose (18F-FDG) uptake on positron emission tomography/computed tomography (PET/CT) with the confirmation of histopathologic findings or with a series of consequent correlative imaging methods.

Methods: A total of 2370 18F-FDG-PET/CT studies performed over a 16-month period in patients with various malignant diseases were retrospectively reviewed. Unexpected PET foci that were in an unusual site for metastatic spread of known malignancy and not considered to be physiologic uptake were evaluated by histopathologic findings or follow-up with correlative imaging methods for a period of 1 year or longer.