Combined hepatocellular and cholangiocarcinoma: correlation between CT findings and clinicopathological features

The purpose of this study was to clarify characteristics of combined hepatocellular and cholangiocarcinoma (HCC-CC) on CT and clinicopathological examinations.

Dynamic incremental CT was performed on 15 combined HCC-CC patients. CT of the early phase was started at 30 s and of the late phase at 120-140 s, after the start of contrast medium injection at a rate of 3 ml/s. The images and clinicopathological findings were retrospectively compared.

Lesions grossly resembling HCC (HCC type, n = 6) were well enhanced in the early phase and changed to low attenuation areas in the late phase. In lesions grossly resembling CC (CC type, n = 9), 8 of 9 lesions were enhanced only at the peripheral portions in the early phase and changed to low attenuation areas or had only central portions enhanced in the late phase. The other CC-type lesion was not enhanced in either the early or the late phase. In all 15 cases, there was no dilatation of the intrahepatic bile ducts. Hepatitis B virus surface antigen was positive in five cases. Hepatitis C virus antibody was positive in 10 cases. Serum alpha-fetoprotein (AFP) levels were > or = 200 ng/ml in seven cases.

In the CC type, enhanced CT images were compatible with CC, but positivities for virus markers and serum AFP levels were almost equivalent to those in HCC. Therefore, the CC type can be diagnosed as combined HCC-CC by evaluating virus markers and serum AFP levels with CT. In addition, no association of intrahepatic bile duct dilatation was considered to be a characteristic feature of combined HCC-CC.