Combined hepatocellular and cholangiocarcinoma (biphenotypic) tumors: imaging features and diagnostic accuracy of contrast-enhanced CT and MRI.

OBJECTIVE: The purpose of this study was to evaluate the diagnostic accuracy of preoperative imaging for diagnosis of combined hepatocellular cholangiocarcinoma tumors and to evaluate the clinical and imaging features and demographics of patients presenting to our institution with such tumors.

MATERIALS AND METHODS: From January 2001 to January 2011, 29 patients presented with pathologically proven combined hepatocellular cholangiocarcinoma tumors to our institution. A retrospective review of the imaging studies, clinical data, and demographic information in these patients was conducted. Two radiologists with 6 and 18 years of experience reviewed the imaging studies of patients with combined hepatocellular cholangiocarcinoma tumors and matched control cases of hepatocellular carcinoma (HCC) (n = 15) and cholangiocarcinoma (n = 18). The reviewers were blinded to the pathologic diagnosis. Imaging features on contrast-enhanced MRI and CT with the suggested final diagnosis were recorded.

RESULTS: The demographics of our patient population were similar to other reported U.S. populations, with cirrhosis and hepatitis present in a minority of patients. The imaging features of combined hepatocellular cholangiocarcinoma tumors overlapped with those of HCC and cholangiocarcinoma. The correct diagnosis of combined hepatocellular cholangiocarcinoma tumors was made in a minority of cases by either radiologist, with misdiagnosis more often leading to suggestion of cholangiocarcinoma than HCC. Sensitivities and specificities for diagnosis of combined hepatocellular cholangiocarcinoma tumors ranged from 33% to 34% and 81% to 100%, respectively.

CONCLUSION: Preoperative diagnosis of combined hepatocellular cholangiocarcinoma tumors on the basis of imaging features is accurate in the minority of cases. Tumor markers and risk factors may help improve accuracy; however, in the absence of classic imaging features and supportive information for HCC or cholangiocarcinoma, biopsy should be considered for confirmation of diagnosis.