Update on the clinical features, treatment and histogenesis of combined hepatocellular-cholangiocarcinoma.

Combined hepatocellular-cholangiocarcinoma (CHC) is a rare subtype of primary liver cancer with histological features of both hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). The clinicopathological features, treatment and histogenesis of CHC remain to be elucidated due to its low morbidity. In total, 26 patients with CHC, 901 patients with HCC and 40 patients with ICC were included in the present retrospective study and their clinicopathological characteristics and prognoses were compared. The treatment patterns of postoperative CHC recurrence were analyzed. Immunohistochemistry for the hepatic progenitor cell (HPC) markers CD90 and epithelial cell adhesion molecule (EpCAM) was performed to investigate the origin of CHC. CHC demonstrated clinicopathological features of both HCC and ICC. Patients with CHC had similar overall survival (OS) and disease-free survival (DFS) rates to those with ICC, but all had significantly lower survival rates compared with those with HCC. Univariate analysis revealed that α-fetoprotein, carbohydrate antigen 19-9, carcinoembryonic antigen, tumor size, macrovascular invasion and lymph node metastasis were risk factors for both OS and DFS. Most patients with recurrent CHC received comprehensive treatment. Immunohistochemistry revealed that patients with CHC exhibited high expression levels of CD90 and EpCAM. In conclusion, compared with patients with HCC and ICC, patients with CHC appear to have intermediate clinical characteristics. Comprehensive postoperative therapy may be a promising strategy for patients with CHC. The high expression level of HPC markers in tumor tissues suggests that CHC may originate from HPCs.