Question: A 56-year-old man underwent annual abdominal ultrasonography (US) as a medical checkup and a mass was found in his portal vein. Further examination was required and he was admitted to our hospital. He had no significant chief complaints, family history, or past medical history. On physical examination, no significant findings were revealed. Laboratory data were as follows: aspartate aminotransferase of 57 IU/L, alanine aminotransferase of 42 IU/L, lactate dehydrogenase of 302 IU/L, and γ-glutamyltransferase of 248 IU/L.