Prognostic impact of cholangiocellular and sarcomatous components in combined hepatocellular and cholangiocarcinoma☆

Combined hepatocellular and cholangiocarcinoma (cHC-CC) is a rare type of liver cancer displaying both hepatocellular and cholangiocellular components. The cholangiocellular carcinoma (CC) in these tumors ranges from focal to prominent. Those cHC-CCs with sarcomatous features are reported to have a poor prognosis. To clarify whether the CC and sarcomatous component affects the prognosis, we classified 40 patients with cHC-CCs into 4 groups according to the presence of a sarcomatous component and the extent of the CC component. Seven (17.5%) tumors showed areas with a sarcomatous component. The remaining tumors were divided into a low-CC group (CC occupying <30% of the tumor, n = 12), a middle-CC group (30%-60%, n = 15), and a high-CC group (>60%, n = 6). Vascular invasion was more frequently present in the high-CC and sarcomatous group than in the other groups (P = .0007). No lymph node metastasis occurred in either the low- or the middle-CC groups, but it was detected in 3 (50%) cases of the high-CC group and in 2 (29%) cases of the sarcomatous group (P < .0001). There was a tendency for tumor size to increase from the low- to the middle- to the high-CC group. The Ki-67 labeling index values for the hepatocellular carcinoma, CC, and sarcomatous components were 11.4% ± 12.9%, 25.4% ± 18.3%, and 46.0% ± 23.6%, respectively. The overall survival of patients in the high-CC and sarcomatous group was significantly poorer than that of patients in the low- and middle-CC groups (P = .0048). By multivariate analysis of overall survival, lymph node metastasis, histological subgroup, and vascular invasion were significant independent prognostic factors. A cHC-CC with a large CC component is as aggressive as cHC-CC with sarcomatous features.