Evaluation of Primary Liver Cancers Using Hepatocyte‐Specific Contrast‐Enhanced MRI: Pitfalls and Potential Tips

Abstract

When radiologists interpret hepatic focal lesions seen on dynamic magnetic resonance imaging (MRI) scans, it is important not only to distinguish malignant lesions from benign ones but also to distinguish nonhepatocellular carcinoma (HCC) malignancies from HCCs. In addition, most major guidelines, including those of the American Association for the Study of Liver Disease, European Association for the Study of the Liver, and Korean Liver Cancer Association and National Cancer Center, allow for the noninvasive imaging diagnosis of HCC in at‐risk patients. However, ~40% of HCC cases show atypical imaging features mimicking non‐HCC malignancies. Furthermore, several benign and malignant lesions, such as flash‐filling hemangioma and intrahepatic mass‐forming cholangiocarcinoma, frequently look like HCC. In contrast, although multiparametric MRI options, including hepatobiliary phase and diffusion‐weighted imaging, provide useful information that could help address these challenges, there remain several unresolved issues with regard to the noninvasive diagnostic criteria characterizing HCC. In this article, we discuss the typical imaging features and challenging situations related to primary liver cancers in MRI, while considering how to make a correct diagnosis. Level of Evidence 5 Technical Efficacy Stage 3

Optimizing the Diagnosis and Biomarker Testing for Patients with Intrahepatic Cholangiocarcinoma: A Multidisciplinary Approach

“…Imaging plays a key role in the diagnosis of iCCA; however, imaging alone is not diagnostic, and no consensus exists on the imaging technique or diagnostic criteria [ 40 , 45 , 46 ]. While there are some imaging features that can suggest iCCA on contrast-enhanced CT and MRI (capsular retraction, rim-arterial phase hyperenhancement, and progressive enhancement on delayed images), ultimately, imaging cannot be definitive in distinguishing primary iCCA from its ‘morphological mimics’ [ 46 , 47 , 48 ].…”

“…However, this pattern is also seen in patients with metastatic lesions from the pancreas, stomach, and small bowel [ 51 ]. Due to the absence of specific diagnostic immunohistochemical biomarkers, iCCA is commonly regarded as a diagnosis of exclusion when a liver mass is found without primary cancer detection via PET-CT or upper/lower endoscopy [ 48 , 51 ]. Further research is needed to help identify definitive diagnostic immunohistochemical biomarkers of iCCA.…”

“…To establish the diagnosis of iCCA and distinguish it from other tumors, it is recommended that specific imaging observations are considered and analyzed [ 46 , 52 ]. HCC may be distinguished from iCCA based on radiological features on a contrast-enhanced imaging study; while HCC lesions show hyperenhancement in the arterial phase and contrast washout in the venous phase, iCCA shows progressive contrast uptake throughout both arterial and venous phases without a washout pattern [ 46 , 47 , 48 ]. iCCA may also be suspected when liver capsule retraction and biliary dilatation are observed in the vicinity of the intrahepatic lesion [ 46 , 47 ].…”

Editorial for “Comparing Survival Outcomes of Patients With LI‐RADS‐M Hepatocellular Carcinomas and Intrahepatic Cholangiocarcinomas”

“…This observation is not clearly explained, but we could surmise some possible explanations. First, included HCCs might have poor prognostic subtypes: HCCs with LR‐M features often include scirrhous HCC, HCC with stemness‐related markers, poorly differentiated HCC and sarcomatoid HCC that are related to poor prognosis 6 . Second, there may be a possibility that small duct type iCCA with relatively better prognosis in iCCA group since small duct type iCCA is more common in patients at risk of developing HCC.…”

“…First, included HCCs might have poor prognostic subtypes: HCCs with LR-M features often include scirrhous HCC, HCC with stemness-related markers, poorly differentiated HCC and sarcomatoid HCC that are related to poor prognosis. 6 Second, there may be a possibility that small duct type iCCA with relatively better prognosis in iCCA group since small duct type iCCA is more common in patients at risk of developing HCC. Third, both HCC and iCCA groups had cirrhosis with different hepatic function which might affect their treatment option.…”