Distinct radiological features of lymphoepithelioma-like intrahepatic cholangiocarcinoma: comparison with classical intrahepatic cholangiocarcinoma.

ABSTRACT

BACKGROUND: Lymphoepithelioma-like intrahepatic cholangiocarcinoma (LEICC) has been recently introduced as a genetically distinct of intrahepatic cholangiocarcinoma (ICC). We aimed to investigate whether LEICC has distinct radiological characteristics in comparison with classical ICC, and to determine MRI features that can be used to differentiate LEICC from classical ICC. METHODS: Five hundred and sixty-seven consecutive patients who underwent surgical resection or liver transplantation for ICC between 2014 and 2021 were retrospectively identified. Among them, 30 patients with LEICC (LEICC-cohort) and 116 with stage-matched classical ICC (control-cohort) were finally included. Pre-operative MRI data were compared between the two cohorts. Multivariable logistic regression analysis was performed to determine relevant imaging features suggesting the diagnosis of LEICC over classical ICC. RESULTS: LEICCs showed significantly higher frequencies of a non-rim arterial phase hyperenhancement (APHE), washout on post-arterial images and a smooth margin, as well as less frequencies of perilesional enhancement and liver capsular retraction when compared with classical ICCs (P < 0.05 for all). The multivariate analysis revealed that non-rim APHE (odds ratio, 10.863; 95% CI [3.295-35.821]; P < 0.001) and the absence of perilesional enhancement (odds ratio, 3.350; 95% CI [1.167-9.619]; P = 0.025) are significant independent imaging features that suggest the diagnosis of LEICCs over classical ICCs. CONCLUSIONS: Compared with classical ICCs, LEICCs do have distinct radiological characteristics. A smooth margin, non-rim APHE, washout on post-arterial images, absent perilesional enhancement and absent liver capsular retraction are useful MRI features that could help to differentiate LEICCs from classical ICCs.