Hepatitis B virus-associated intrahepatic cholangiocarcinoma: a malignancy of distinctive characteristics between hepatocellular carcinoma and intrahepatic cholangiocarcinoma.

It has been a decade since hepatitis B virus infection was identified as an etiological factor for the development of intrahepatic cholangiocarcinoma (ICC). In recent years, several studies have elucidated the critical impact of hepatitis B virus in ICC that significantly influenced the clinicopathological characteristics of ICC patients with intrahepatic cholangiocarcinoma. Distinctive features of patients with hepatitis B virus-associated ICC included younger age, preponderance of male patients, frequent elevation of alpha-fetoprotein, and infrequent lymph node metastasis. Furthermore, several studies indicated that the presence of hepatitis B virus is a favorable prognostic factor in terms of overall survival and relapse-free survival. However, there are also a few studies demonstrating that hepatitis B virus negatively influenced or showed no significant association with survival outcomes of patients with ICC. At present, there are no consensus on diagnostic procedures and treatments for such population. Therefore, we elucidated current knowledge and recent identifications of HBV-associated ICC to clarify the impact of chronic HBV infection on patients with ICC and to precisely conduct diagnostic procedures and curative treatments for HBV-associated ICC.