| BackgroundHepatocellular carcinoma (HCC) is the most common primary tumor in liver. The incidence of HCC all over the world has increased rapidly since the mid of 1990s, and it is expected to rise in the next 2 decades. In China, the incidence of HCC is high. More than 50% of new patients occur in China in the world, and its mortality is in the second place only after that of carcinoma of the lungs. The radio of male and female of HCC is about 2.7:1. Chronic hepatitis is the major pathogenic factor of HCC in China, while the nodular cirrhosis of the liver based on that is the common feature of HCC. High malignancy, invasion and metastasis of HCC determine that the prognosis of patients mainly depends on whether early diagnosis and early treatment are obtained. In recent years, with the development of imaging techniques, imaging examination has become a major means of all examinations in early diagnosis of HCC. In spite of this, there are still some lesions which are difficult to diagnose due to lack of typical imaging findings. So we need to look for other defining and imaging characteristics in order to improve the level of diagnosis of HCC with imaging examinations. At the same time, complex imaging characteristics of HCC also need to be studied and described from theory aspect, so as to deepen the theoretical mechanism of HCC imaging findings.Researches in recent years found that fibrotic stroma occupies a large proportion in the composition of tumor, where mainly distributes within the tumor and the edge. Fibrotic stroma can be generally enhanced in delay phase, and Contrast medium enhanced MR scanning shows more unique values in detecting that in HCCs. And the typical capsular enhancement appears at a rate of 60% -82%, which is an important hint of HCC diagnosis. But now for the relations of delayed enhancement in HCC with fibrotic stroma, there are still many problems to be further discussed, such as the different influences on delayed enhancement of fibrous tissue within the tumor or in the edge, and different influences on delayed enhancement of elastic, collagen and reticular fibers which constitute fibrotic stroma. Recent studies found that delayed capsular enhancement is related to prominent sinusoids and fibrotic stroma. Therefore, impacts of different fibers and other factors on delayed enhancement of HCC and other problems all need further to be studied. Based on this, this research collected pathologic specimens of HCC which were confirmed by surgery and pathology, and we observed pathological parameters in fibrous capsules, in the liver tissue around the tumors and within the tumors (fiber interval and nests). Pathological parameters included purities and distribution forms of three kinds of fibers, blood vessels in fibrous capsules (FC), adjacent liver sinus’condition, the degrees of inflammatory cells infiltration, tumor sizes and AFP levels etc. And we investigated the relationships between the above factors and MR delayed enhancement, so as to clarify the main factors influencing the HCC delayed enhancement and deepen the mechanism of imaging findings of HCC, providing new information for HCC diagnosis from a new angle and improving its diagnostic level.ObjectiveTo investigate the relationships between pathological parameters included purities and distribution forms of three kinds of fibers, blood vessels in FCs, adjacent liver sinus’ condition, the degrees of inflammatory cells infiltration, tumor sizes and AFP levels with delayed enhancement, study mechanisms of delayed enhancement of HCC and figure out its diagnostic values.MethodsWe collected 28 patients with HCC who accepted surgical treatment and be confirmed by routine pathology and also had typical annular enhancement on delayed phase images from June 2012 to December 2014 in Qilu hospital of Shandong university. We sampled 2-6 lumps of 22 patients within the tumors and on the edges according to the sizes of tumors. For the rest 6 patients, we only sampled 2-6 lumps within the tumors. And then we observed purities and distribution forms of three kinds of fibers in FCs, in the liver tissue around the tumors and within the tumors by using special dyeing (resorcinol fuchsin staining, Masson trichromatic staining and silver ammonia hydroxide solution impregnation staining method respectively for elastic, collagen and reticular fibers). We also observed Pathological parameters including the thicknesses of FCs, degrees of inflammatory cells infiltration, differentiation degrees of tumors, tumor sizes, numbers of capsular vessels in FCs, serum AFP levels. And then we studied the relations between factors above and MR delayed enhancement.ResultsAmong these 28 cases 24 patients were male, and 4 patients are female. They aged 22 to 63 years old, the average and medium were 54.9±1.8 and 56.5 respectively. We studied 22 fibrous capsules (FC), and in these FCs, three kinds of fibrous stroma were cross existing and their purities had no obvious difference in these FCs. Among these FCs, there were 18 FCs whose thicknesses were medium or thicker, in which fibers’distributions had certain regularity:very next to the tumors, the distribution density was high, and gradually got loose to the outside.4 FCs were very thin, and in which distributions of fibers had no regularity. And all these 22 tumors had delayed circular reinforcement in the enhanced MR imaging. Of the 22 HCCs, all tumors were lateral infiltrated with inflammatory cells with different degrees, among which 7 tumors were mild inflammatory infiltrated,8 tumors were moderate inflammatory infiltrated,7 tumors were obvious inflammatory infiltrate. Around 15 HCCs, there were prominent sinusoids, and the average thickness of their delayed circular enhancement was 1.96 ± 0.04 mm. Around 7 HCCs there were liver tissues compressed and the average thickness of their delayed circular enhancement was 1.94 ±0.06 mm. We studied 28 tumors from 28 patients with their delayed enhancement degree and the distributions of three kinds of fibers. Statistical results were as follows:thicknesses of delayed circular enhancement of 22 HCCs were closely related to the thicknesses of pathological FCs (P= 0.004), and were also closely related to the amounts of blood vessels in FCs(P= 0.003), and were related to inflammatory infiltration around FCs (P=0.013), but had no significant correlation with the tumor sizes and differentiation degrees (P> 0.05). At the same time, the degrees of delayed circular enhancement of 22 HCCs were related to the amounts of blood vessels inside the FCs (P< 0.05), but had no correlations with thicknesses of pathological FCs, inflammatory cells infiltration, tumor sizes and tumor differentiation degrees (P> 0.05). In addition, for the 28 HCCs of 28 patients, the degrees of delayed enhancement inside tumors were closely related with collagen fibers, elastic fibers and reticular fibers (P< 0.001), but had no correlations with internal nests and tumor necrosis (P> 0.05). Serum AFP levels of HCC patients had no significant correlation with fibers inside tumors (P> 0.05).Conclusion(1) Fibers were closely related to the HCCs’ delayed enhancement of MRI, but the correlations of three kinds of fibers with delayed capsular enhancement were not clear.(2) Thicknesses of delayed circular enhancement of 22 HCCs were closely related to the thicknesses of pathological FCs, and were also closely related to the amounts of blood vessels in FCs, and were related to inflammatory infiltration around FCs, but had no significant correlation with the tumor sizes and differentiation degrees.(3) The enhanced degrees of delayed circular enhancement of 22 HCCs were related to the amounts of blood vessels inside the FCs, but had no correlations with thicknesses of pathological FCs, inflammatory cells infiltration, tumor sizes and tumor differentiation degrees.(4) The degrees of delayed enhancement inside tumors were closely related with collagen fibers, elastic fibers and reticular fibers, but had no correlations with internal nests and tumor necrosis.(5) Serum AFP levels of HCC patients had no significant correlation with fibers inside tumors. |
