Combined Hepatocellular Cholangiocarcinoma (Biphenotypic) Tumors: Potential Role of Contrast-Enhanced Ultrasound in Diagnosis.

OBJECTIVE: The objective of this study was to evaluate the diagnostic performance of contrast-enhanced ultrasound (CEUS) in differentiating combined hepatocellular cholangiocarcinomas (CHCs) from hepatocellular carcinomas (HCCs) and intrahepatic cholangiocarcinomas (ICCs). MATERIALS AND METHODS: Thirty-three patients with pathologically confirmed CHC and matched control subjects with pathologically confirmed HCC (n = 30) or ICC (n = 32) who underwent preoperative CEUS from January 2005 to December 2015 were enrolled in this study. The CEUS images of the hepatic lesions were subjectively analyzed in consensus by two radiologists. The diagnostic performances were evaluated by ROC analysis. RESULTS: In the arterial phase, hyperenhancement was more common in CHCs (76%) and HCCs (100%) than in ICCs (22%), whereas in the late phase marked washout was more common in CHCs (76%) and ICCs (100%) than in HCCs (10%). Using marked washout in the late phase to differentiate CHC from HCC, the area under the ROC curve (AUC) was 0.829, and the sensitivity, specificity, and accuracy were 78%, 90%, and 83%, respectively. Using hyperenhancement in the arterial phase followed by marked washout in the late phase to distinguish CHC from ICC, the AUC value was 0.663, and the sensitivity, specificity, and accuracy were 55%, 78%, and 66%. CONCLUSION: Although the imaging features of CHC, HCC, and ICC on CEUS may overlap, CEUS could be used in the differential diagnosis of CHC from HCC and ICC.