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Biphenotypic primary liver carcinoma may be misclassified as HCC

Biphenotypic primary liver carcinoma — also called hepatocholangiocarcinoma — may be misclassified as hepatocellular carcinoma if interpretation is based on major imaging features alone and not additional ancillary features, according to recent findings published in the American Journal of Roentgenology.

“Most of these malignancies have at least one ancillary feature that may allow them to be correctly classified as a non-HCC malignancy,” Theodora A. Potretzke, MD, in the department of radiology at Mayo Clinic, Rochester, Minn., said in a press release. “The results of our study support the importance of a more comprehensive algorithm for liver lesion assessment, such as Liver Imaging Reporting and Data Systems (LI-RADS).”

Theodora A. Potretzke

Biphenotypic primary liver carcinoma can mimic HCC in as many as 40% of cases, Potretzke and colleagues wrote. To determine the frequency of misclassification, they performed a review of 61 patients (mean age, 62 years) with biphenotypic carcinomas diagnosed at the Mallinckrodt Institute of Radiology in St. Louis between 2006 and 2014.

Two abdominal imagers independently reviewed cases using LI-RADS version 2014. They determined the number of lesions meeting HCC requirement first after using the major features of LI-RADS alone and then after using additional ancillary features.

After using the major features alone, 33 of the 61 lesions met criteria for HCC, suggesting that they were misclassified. After evaluation of ancillary features, 29 of the 33 potential misclassifications showed at least one ancillary feature favoring non-HCC malignancy, suggesting that they were appropriately reclassified. Of the four remaining potential misclassifications, only two (3.3% of all tumors) fell within the Milan criteria for HCC.

These data emphasize the importance of including ancillary features and tie-breaking rules for assigning a final diagnosis, the researchers wrote.

“Our study provided valuable information regarding the frequency of major and ancillary features of biphenotypic primary liver carcinoma,” they wrote. “That a substantial percentage of lesions met strictly applied major feature criteria for HCC raises concern that the use of imaging algorithms that do not account for ancillary features may lead to misdiagnosis in some instances.” – by Will Offit

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