| BackgroundPrimary hepatic carcinoma(PHC)is the most common malignant tumor in the upper abdomen disease,including three pathological types:hepatocellular carcinoma(HCC),intrahepatic cholangiocarcinoma(ICC)and mixed hepatocellular cholangiocarcinoma.HCC accounts for the highest proportion and the most malignant degree.ICC is the second malignant tumor of the liver,and the incidence is increasing in recent years.HCC originates from malignant tumour of the liver cells and always has a history of b viral hepatitis and cirrhosis.Generally,it is accompanied by a rise in AFP in the laboratory examination.ICC derives from small intrahepatic bile duct epithelial cells of malignant tumor and has close relationship with stones and chronic infection,with increased levels of CA199 in the laboratory examination.With the development of imaging technology,the location and qualitative diagnosis of PHC is becoming more and more obvious.For example,ultrasound,CT and MRI play an increasingly important role in the screening,diagnosis and therapeutic evaluation of PHC.In various imaging techniques,MRI has become the most important technology for detecting liver diseases because of its advantages such as no ionizing radiation,multi parameter,high soft tissue and spatial resolution.The application of contrast enhancement has significantly improved its detection efficiency.On MRI analysis,the most frequently occurring enhancement patterns present in HCC were the washout patterns while the most frequently occurring enhancement patterns of ICC were progressive patterns,so theoretical identification is not difficult.However,part of HCC does not appear classic washout patterns but shows "fast in slow out" or "slow in slow out",which was named atypical hepatocellular carcinoma(aHCC)in actual clinical diagnosis.aHCC has certain similarities with the ICC in the MRI performance,leading to difficulty in the differential diagnosis.Therefore,it is of great significance to identify the factors that lead to the similarity of the two images from the mechanism.The reason of delayed enhancement of aHCC and ICC mainly include vascular and fibrous factors,and the value of the latter has been paid more attention in recent years.Delayed enhancement of tumor is closely related to fibrous stroma.Due to the dense connection of fibrous tissue and the large fiber-to-fiber spacing,the entry and removal of contrast media is relatively slow,so there is a typical delayed phase enhancement.Since aHCC and ICC contain more fibrous tissues,MRI enhanced delayed detection is a non-invasive examination and has important diagnostic value in the diagnosis of primary liver cancer.Tumors are rich in fibrous interstitium,but fibrous tissue components are complex,including not only fibrous tissue,but also blood vessels,lymphatic vessels and inflammatory cells.Fibrous tissue includes collagen fibers,elastic fibers and reticular fibers.In addition to vascular and fibrous tissue factors,the effect of other fibrous stroma components on delayed enhancement of tumor and its value in the diagnosis and differential diagnosis of primary liver tumors need further study.At present,the research is rare between internal fiber in ICC and aHCC and the effect of delayed enhancement,so intensive study can explore the mechanism of the two similar theory.what’s more,based on this,we can improve the understanding of the characteristics of the two types of diseases in the delayed enhancement,and promoting the improvement of the level of diagnosis and identification.ObjectivesTo investigate the intrahepatic cholangiocarcinoma(ICC)and atypical hepatocellular carcinoma(aHCC)in MRI delayed contrast-enhanced features and relationship between pathological parameters included purities and distribution forms of there kinds of fibers,blood vessels and the degree of inflammatory cells infiltration with delayed enhancement,study mechanism of HCC and figure out its diagnostic values.MaterialsWe collected 40 patients with ICC and aHCC who accepted surgical treatment and be confirmed by routine pathology and also had delayed enhancement images from June 2013 to June 2017 in Qilu Hospital of Shandong University,inlcuding 19 cases of ICC and 21cases of aHCC.The 5minutes delayed image was used to evaluate the degree of enhancement in the delay period.Other images were used to evaluate the imaging features of bile duct dilatation,ascites,lymph node metastasis and so on.And then we observed purities and distribution forms of three kinds of fibers and vessel numbers within the tumors by using HE staining and special dyeing(picric-sirius red staining,Verhoeff Van-Gieson staining and Gordon-Sweets staining method respectively for collagen,elastic and reticular fibers).We also observed the degrees of inflammatory cells infiltration and differentiation degrees of tumors.And then we studied the relations between factors above and MR delayed enhancement.ResultsIn this study,40 cases were reported,including 19 cases of ICC and 21 cases of aHCC.In study,there were 29 males and 11 females with an average age of 56 years.There was a significant difference between ICC and aHCC in the number of three kinds of fibrous tissue(P<0.05).The number of ICC in collagen fiber,elastic fiber and reticular fiber was more than that of aHCC.There was also a significant difference in the degree of delayed enhancement between ICC and aHCC(P<0.05).The main manifestation of ICC was obviously delayed enhancement,but aHCC generally showed delayed mild to moderate enhancement.For ICC and aHCC,the degree of delayed enhancement is closely related to the number of three kinds of fibrous tissue(P<0.05),but there is no significant correlation between the degree of delayed phase and the degree of inflammatory cell infiltration(P>0.05).There was a significant difference in the number of vessels between ICC and aHCC(P<0.05).The number of vessels in ICC was less than that in aHCC,but there was no significant difference in the degree of delayed enhancement of ICC and aHCC and the number of vessels in each group(P>0.05).ICC and aHCC also had statistical differences with or without extrahepatic bile duct dilatation and fiber hyperplasia(P<0.05),ICC is more easily associated with intrahepatic bile duct dilatation and aHCC is more prone to liver fibrosis,but there was no significant difference in other MRI signs(ascites,lymph node metastasis and portal vein invasion)(P>0.05).Conclusions1.The number of ICC in collagen fiber,elastic fiber and reticular fiber is more than that of aHCC.2.The number of blood vessels in aHCC is more than that of ICC.3.The main manifestation of ICC is that the delay period is obviously enhanced,but aHCC is generally characterized by light or moderate in the delay period.4.For ICC and aHCC,the degree of delayed phase is closely related to the number of three kinds of fibrous tissue.However,there is no significant relationship between the degree of delayed phase enhancement and the number of vessels and the infiltration of inflammatory cells.5.On the imaging features,ICC is more likely to be associated with the expansion of the intrahepatic bile ducts while aHCC is more likely to develop fibrosis of the peripheral liver tissue. |
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