A 62-year-old female was admitted for examination of an abnormal liver function. Plain CT and MRI of the abdomen showed marked hepatomegaly but no visible nodular lesion in the liver. On the 3rd hospital day she had hepatic encephalopathy and was treated with a course of high-dose steroids, but ultimately died of disease progression on the 7th hospital day. An autopsy revealed a small pulmonary nodule with the histological findings showing small cell carcinoma. There was almost complete parenchymal replacement with metastatic tumor in the liver. Neoplastic involvement of the liver should be considered in the differential diagnosis of fulminant hepatic failure of unknown etiology.