Calyceal Diverticulum in FDG-PET Imaging

A 46-year-old female underwent a fluorodeoxyglucose F-18 (FDG) positron emission tomography (PET) whole-body scan for tumor screening after showing no symptoms or signs. The PET images showed a large FDG-avid lesion in the left renal pelvis, with a maximum standard uptake value (SUV) of 10.7 at 1 hour and 3.9 at 3 hours. An abdominal computed tomography (CT) scan showed a 3.7-cm cystic lesion with a slightly irregular wall in the left kidney. The immediate impression was that of a complicated cyst. A histopathologic report after surgery confirmed a calyceal diverticulum. To the best of our knowledge, this is the first report of FDG uptake in a case of calyceal diverticulum.