Combined Hepatocellular‐Cholangiocarcinoma: Magnetic Resonance Imaging Features and Prognosis According to Risk Factors for Hepatocellular Carcinoma

Background Combined hepatocellular‐cholangiocarcinoma (cHCC‐CCA) can develop in patients with and without risk factors for hepatocellular carcinoma (HCC). Purpose To compare the clinical and magnetic resonance imaging (MRI) characteristics of cHCC‐CCA in patients with and without risk factors for HCC, and to assess the influence of risk factors on patient prognosis. Study Type Retrospective. Population A total of 152 patients with surgically confirmed cHCC‐CCA. Field Strength/Sequence 1.5‐T and 3‐T/T1‐weighted dual gradient‐echo in‐ and opposed‐phase, T2‐weighted turbo‐spin‐echo, diffusion‐weighted single‐shot spin‐echo echo‐planar, and T1‐weighted three‐dimensional gradient‐echo contrast‐enhanced sequences. Assessment MRI features according to the Liver Imaging Reporting and Data System (LI‐RADS) and pathologic findings based on revised classification were compared between patients with and without risk factors for HCC. Overall survival (OS) and recurrence‐free survival (RFS) were also compared between the two groups, and factors associated with survival were evaluated. Statistical Tests The clinico‐pathologic and MRI features of the two groups were compared using Student's t‐tests, Mann–Whitney U‐tests, and chi‐square tests. OS and RFS were evaluated by the Kaplan–Meier method, and factors associated with survival were evaluated by Cox proportional hazard model. Results cHCC‐CCA in patients with risk factors were more frequently classified as LI‐RADS category 4 or 5 (LR‐4/5; probably or definitely HCC) (48.7%), whereas those without risk factors were more frequently classified as category M (LR‐M; probably malignant, not specific for HCC) (63.6%). RFS and OS did not differ significantly according to risk factors (P = 0.63 and 0.83). Multivariable analysis showed that pathologic tumor type (hazard ratio 2.02; P