A 28-year-old female visits the outpatient clinic to receive the required physical examination for an insurance policy. Physical and laboratory examinations give evidence that she is probably a normal, healthy woman. A radiograph of the patient is shown. Which of the following is the most likely diagnosis?

(c) Source: GAS 316-317; GA 142-143, 162 Because physical and laboratory tests show a normal, healthy woman, the anomaly of the radiograph would be expected to be benign. Riedel's lobe is a normal variation of the liver, often an inferior extension of the right lobe of the liver, lateral to the gallbladder that extends about 4 or 5 cm below the rib cage. Carcinomas would present with abnormal laboratory examinations, and cholecystitis would present with an abnormal physical examination, as when the gallbladder is inflamed.