ORIGINAL RESEARCH Combined Hepatocellular- Cholangiocarcinoma: Gadoxetic Acid-Enhanced MRI Findings Correlated With Pathologic Features and Prognosis So Hyun Park, MD, 1 Seung Soo Lee, MD, 1 * Eunsil Yu, MD, 2 Hyo Jeong Kang, MD, 2,3 Yangsoon Park, MD, 2 So Yeon Kim, MD, 1 So Jung Lee, MD, 1 Yong Moon Shin, MD, 1 and Moon Gyu Lee, MD 1 Purpose: To evaluate gadoxetic acid-enhanced magnetic resonance imaging (MRI) findings of combined hepatocellular cholangiocarcinoma (cHCC-CC) with special emphasis on correlation of MRI findings with histopathologic tumor charac- teristics and survival outcomes after curative surgery. Materials and Methods: Our Institutional Review Board approved this study, with a waiver of informed consent. For 82 patients (64 men, 18 women; mean age, 54.0 years; age range, 30–81) with surgically confirmed cHCC-CCs, we evaluat- ed clinical features, histologic findings, and tumor morphologic and enhancement features on gadoxetic acid-enhanced liver MRI at 1.5T (n 5 67) or 3.0T (n 5 15). Imaging features of cHCC-CCs were correlated with pathologic findings according to the 2010 World Health Organization classification system. Tumors were categorized as hypervascular or nonhypervascular based on arterial phase enhancement and were compared with respect to overall and recurrence-free survival after curative-intent surgery. Results: Of the 82 lesions, 48 showing global arterial phase enhancement were categorized as the hypervascular group, while 34 lesions demonstrating rim, peripheral, or isoenhancement were categorized as the nonhypervascular group. There was no significant difference in MRI findings between pathologic tumor types (classical type versus stem cell fea- ture type, P 5 0.324–1.0). Compared with the nonhypervascular group, the hypervascular group had a larger HCC com- ponent (P 5 0.014), smaller CC component (P 5 0.001), and lesser amount of fibrotic stroma (P 5 0.006) on pathologic analysis and was an independent factor associated with better overall survival after surgical resection (P 5 0.033). Conclusion: Gadoxetic acid-enhanced MRI findings of cHCC-CCs were diverse, reflecting heterogeneous histologic fea- tures. The hypervascular group on MRI is associated with a larger HCC component, smaller CC component, less fibrotic stroma, and better overall survival after curative surgery than the nonhypervascular group. Level of Evidence: 4 J. MAGN. RESON. IMAGING 2016;00:000–000 C ombined hepatocellular cholangiocarcinoma (cHCC-CC) is an uncommon primary liver cancer, accounting for 1.1– 6.3% of all primary liver cancers, 1–3 which comprises a mixture of hepatocellular carcinoma (HCC), cholangiocarcinoma (CC), and/or components with hepatic progenitor/stem cell (HPC) features 4–9 ; cHCC-CC reportedly has a poorer postsurgical/- transplantation prognosis than HCCs. 10–16 With an increasing understanding of the role of HPCs in the development of cHCC- CCs, the 2010 World Health Organization (WHO) classification system categorized cHCC-CCs into classical type and subtypes with stem cell features. 4 However, this classification system’s clini- cal and prognostic implications are still controversial. 5–8 View this article online at wileyonlinelibrary.com. DOI: 10.1002/jmri.25568 Received Sep 18, 2016, Accepted for publication Nov 11, 2016. *Address reprint requests to: S.S.L., Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Korea. E-mail: seungsoolee@amc.seoul.kr Current address for S.H. Park: Department of Radiology, Gil Medical Center, Gachon University, 21, Namdong-daero 774beon-gil, Namdong-gu, Incheon, 21565, Korea. From the 1 Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea; 2 Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea; and 3 Department of Physiology, University of Ulsan College of Medicine, Seoul, Korea V C 2016 International Society for Magnetic Resonance in Medicine 1