Combined hepatocellular-cholangiocarcinoma: Gadoxetic acid-enhanced MRI findings correlated with pathologic features and prognosis.

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 characteristics 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 evaluated clinical features, histologic findings, and tumor morphologic and enhancement features on gadoxetic acid-enhanced liver MRI at 1.5T (n = 67) or 3.0T (n = 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 feature type, P = 0.324-1.0). Compared with the nonhypervascular group, the hypervascular group had a larger HCC component (P = 0.014), smaller CC component (P = 0.001), and lesser amount of fibrotic stroma (P = 0.006) on pathologic analysis and was an independent factor associated with better overall survival after surgical resection (P = 0.033).

Conclusion: Gadoxetic acid-enhanced MRI findings of cHCC-CCs were diverse, reflecting heterogeneous histologic features. 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 2017;46:267-280.