Possibility of Differential Diagnosis of Small Polypoid Lesions in the Gallbladder Using FDG-PET

Purpose: We discuss three cases of patients with small polypoid lesions of gallbladder in which we successfully differentiated the malignancy or benignity preoperatively using positron emission tomography (PET) scanning with 18F-labelled deoxyglucose (FDG).Methods and Results: The first case involves a 47-year-old woman who had a 15 x 10 mm polypoid lesion of the gallbladder. FDG-PET was performed and revealed no FDG uptake. The histopathological diagnosis was a cholesterol polyp. The second case is a 56-year-old woman who had a 22 x 8 mm polypoid lesion in the neck of the gallbladder and wall-thickening of the fundus. FDG-PET was performed and no FDG uptake was found. The postoperative diagnosis was pseudo-tumorous sludge in the neck and adenomyomatosis of the fundus. The third case is a 77-year-old man who had a 15 x 15 mm polypoid lesion in the gallbladder. PET revealed a focus of FDG uptake at the site of the gallbladder. The histopathologic diagnosis was adenocarcinoma. Focal FDG uptake was the sole indicator of a malignant tumor of the gallbladder.Conclusions: FDG-PET may become one of the most useful tools for the accurate preoperative diagnosis of gallbladder carcinoma.