Positron emission tomography using F-18 fluorodeoxyglucose (FDG-PET) has an evolving role in the management of oncological patients. Normal FDG biodistribution and potential pitfalls must be considered for accurate interpretation. A 74-year-old patient with a history of seminoma was referred to PET/CT department to evaluate intraabdominal lymphadenopathies and a hyperrnetabolic mass lesion in the left inguinoscrotal region, which raised the suspicion of seminoma recurrence. Main excretion of FDG via urine makes renal collecting systems, ureters and bladder possible sites of confounding findings on PET images. In this paper, we presented F-18 FDG accumulation in a bladder hernia, which is a rare condition that may be misdiagnosed as recurrence. Familiarity with this incidental finding can avoid false interpretations.