Role of MRI in distinguishing intrahepatic cholangiocarcinoma from poorly differentiated hepatocellular carcinoma

Abstract

ObjectivesTo evaluate the role of MRI in the diagnosis of mass-forming intrahepatic cholangiocarcinoma (mICC), its enhancement pattern with contrast agent, and distinction from poorly differentiated hepatocellular carcinoma (pHCC).BackgroundmICC is the second most common primary hepatobiliary tumor that is increasing in incidence. Imaging characteristics in mICC differ significantly, having overlapping imaging features with pHCC. Thus, it is important to differentiate mICC from pHCC.Patients and methodsA retrospective MRI study was conducted on 15 patients with mICC and 15 patients with pHCC referred to MRI unit of the National Liver Institute, Menoufia University from June 2017 to January 2019. MRI were analyzed for tumor shape, intratumoral hemorrhage, fibrous capsule, T2 signal intensity, capsular retraction, intratumoral fat, biliary dilatation, vascular invasion, intraductal lesion, intrahepatic metastasis, restricted diffusion, and enhancement pattern after contrast injection. Associations between MRI features and tumor type were examined using the Fisher's exact and χ2 tests.ResultsLate enhancement was more common in mICC than pHCC (P < 0.001). T2 central hypointense area was more common in mICC versus HCC (P = 0.001). Capsular retraction was more common in mICC than HCC (P = 0.001). Biliary dilatation was more common in mICC than pHCC (P = 0.001). Fat component was more in pHCC than mICC (P = 0.01). Fibrous capsule was more common in pHCC than mICC (P = 0.002). Others parameters were not significant.ConclusionBiliary dilatation, central fibrosis, overlying capsular retraction, and late enhancement at 3 min with absence of fat and fibrous capsule appear to be the most important characteristics for mICC and help its differentiation from pHCC.