Large liver cell adenoma —Consideration in the differential diagnosis with well-differentiated hepatocellular carcinoma—

A 33-year-old female patient underwent extended right lobectomy for a large tumor in the liver. Histologic examination of the resected specimen disclosed obvious differentiation toward hepatocytes in tumor cells and scanty atypia in nuclei. Liver cirrhosis was not combined. These findings were compatible with those of liver cell adenoma. Although differention between liver cell adenoma and well-differentiate dhepatocellular carcinoma(Edmondson grade I) is deemed difficult, it is our opinion that the diagnosis of liver cell adenoma can be made by following characteristics: 1) incidence in young adult 2) no underlying liver disease 3) large tumor in the majority of cases 4) histologic findings of monotonous growth and scanty atypia. However, it is not unequivocally provent hat liver cell adenoma is really a benign neoplasm. Further follow-up study is necessary to confirm its biological property.