A 55-year-old asymptomatic woman underwent F-18 fluorodeoxyglucose PET/CT scan to evaluate a hepatic nodule incidentally detected by ultrasonography during her health examination. The PET/CT images revealed a focus of abnormal fluorodeoxyglucose uptake in a hypoattenuating lesion seen on CT in the medial left lobe of the liver, suggestive of possible malignancy. Surgery was performed and histopathology revealed atypical adenomatous hyperplasia accompanied by extensive fatty degeneration.