A 70-year-old Japanese man underwent distal gastrectomy for gastric cancer. Preoperative computed tomography detected no tumor in the liver. Six months after the operation, ultrasound examination revealed a hyperechoic mass, measuring 3 cm in diameter, in the medial segment of the liver. Dynamic computed tomography of the liver also revealed that low-density area with mosaic enhancement in the dorsal portion of the medial segment. Assay for hepatitis B surface antigen was positive. Levels of carcinoembryonic antigen and alpha-fetoprotein were normal. Computed tomography during arterial portography revealed a perfusion defect in the area corresponding to the mass lesion. Although laparotomy was performed, no abnormality was found in the dorsal portion of the medial segment on inspection and palpation during surgery. We therefore performed incisional biopsy and frozen histologic examination, which revealed fatty deposition in the hepatic parenchyma and no evidence of malignancy. Finally, histologic examination made a diagnosis of macrovesicular steatosis surrounded by normal liver parenchyma.