Perirenal 18F-FDG Uptake in a Patient with a Pheochromocytoma

Increased 18 F-fluorodeoxyglucose (FDG) uptake of brown fat on 18 F-FDG positron emission tomography (PET) originating from physiological activation is a common incidental finding and is usually located in the neck, shoulder, and supraclavicular areas. We present a case of an incidental pheochromocytoma showing diffusely increased 18 F-FDG uptake in bilateral perirenal fat tissue as well as supraclavicular and paravertebral fat tissue on 18 F-FDG PET/CT. The patient had no clinical symptoms except hypertension, and a pheochromocytoma was confirmed in a postsurgical specimen. A pheochromocytoma should be considered a cause in cases of increased 18 F-FDG uptake of perirenal brown fat.