This 3-year-old boy was referred to our hospital because of abdominal tumor. Examination of the abdomen revealed a hard nodular mass in the right hypochondrium. All laboratory studies were normal. A hepatic arteriogram disclosed a large vascular mass with tortous and enlarged arteries. The capillary phase demonstrated a well-demarcated mass with a dense homogenous stain. CT scan showed the tumor had hypodensity compared to the remaining liver tissues. At surgery, the tumor was found to be confined to the medial segment of the left lobe of the liver. Extended right hepatic lobectomy was done and pathologic examination revealed a mass with a central area of collagenous scarring which had fibrous septa radiating from it. Microscopically, the fibrous septa contained proliferating bile ductules and exhibited chronic imflammatory cell response. There were no central veins in the nodules of uniform hepatocytes. Kupffer cells were recognized. Pathological diagnosis was focal nodular hyperplasia of the liver. Postoperative course was uneventful. 20 other cases of focal nodular hyperplasia in Japanese literature were collected and reviewed.
