All That Glitters Is Not Gold" - A Case of an Occult Foreign Body in the Lung with Elevated 2-[18F]-Fluoro-2-deoxy-D-glucose (FDG) Uptake Mimicking Bronchogenic Carcinoma

Combined positron emission tomography/computed tomography (PET/CT) using the glucose analogue 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) has become the standard of care in oncological patients. However, due to the non-specific nature of FDG uptake, there are many physiological variants and benign pathological entities that also demonstrate augmented glucose metabolism, such as inflammatory and infective processes. Undiagnosed and retained foreign bodies (occult foreign bodies) in the lung can induce inflammatory reaction consisting of polymorphonuclear neutrophils, macrophages, and granulation tissue resulting in intense FDG uptake because of high metabolic activity and cell turnover. Here, we present a case of an occult foreign body imitating a tumor on PET/CT.