胆道闭锁肝内外胆系组织病理形态学分析

Analysis of the pathomorphology of intra-and extrahepatic biliary system of biliary atresia

目的通过胆道闭锁(BA)肝门纤维块、肝脏组织的病理及其超微结构观察,对肝门成纤维细胞分化程度进行评分,并与肝纤维化分级进行相关分析。方法选取BA患儿作为研究对象,术中取肝门纤维块及肝脏组织标本;研究同期选取疑似BA经术中胆道造影除外BA,诊断为胆汁淤积综合征和先天性胆管扩张症患儿作为对照组,留取肝脏组织标本。在光镜和电镜下观察标本的病理改变,以及肝细胞、毛细胆管和肝门成纤维细胞的超微结构。采用SPSS14.0软件,半定量比较BA与对照组肝脏纤维化的差异,检验肝门纤维块成纤维细胞活跃程度与肝纤维化分级的相关性。结果2005年7月至2006年5月复旦大学附属儿科医院收治的21例BAKasai根治术病例,手术平均年龄(66±20)d;对照组为5例胆汁淤积综合征和10例先天性胆管扩张症患儿。BA组肝组织病理改变主要是肝内门脉区胆管炎症及纤维化形成,肝纤维化程度明显高于同年龄胆汁淤积综合征和先天性胆管扩张症患儿;肝门纤维块毛细胆管增生,部分管腔闭锁、狭窄,腔内炎细胞浸润及部分淤胆,大量间质成分增生;电镜下肝门成纤维细胞活跃、肝脏毛细胆管上皮微绒毛缺失、肝细胞及肝血窦内电子致密物质增多及部分毛细胆管扩张;肝门成纤维细胞分化程度与肝组织纤维化程度相关(P=0.04)。结论BA肝组织病理改变主要是肝内门脉区胆管炎症及严重纤维化形成;超微结构改变提示肝门部成纤维细胞活跃,其分化程度与肝纤维化程度相关。

Objective Biliary atresia is a common, cholestatic disease with unknown cause and poor prognosis in infants. The pathologic change of biliary atresia is the key to understand its pathogenesis and prognosis. The aim of this study is to observe the pathomorphologic changes in liver and triangular cord of porta hepatis in early biliary atresia and to assess the relationship between the differentiated degree of fibroblast in triangular cord of porta hepatis and the liver fibrosis scores. Methods From September 2005 to May 2006, 21 cases of biliary atresia [ （66 ± 20） days old] underwent Kasai procedure. Liver tissues and triangular cord of porta hepatis were taken during operation. 5 cases of cholestasis syndrome and 10 cases of choledochal cyst were taken as control group. Liver biopsy was done in the control group. The micro- and ultra-structure of the liver and porta hepatis were assessed between biliary atresia and the control group. Phillip CM-120 transmission electron microscope was used to examine the ultra structure features, including hepatocyte, canalicule and fibroblast. Semi-quantitatively the difference of the liver fibrosis grading between biliary atresia and control group was evaluated with a 3 grade staging system. The differentiated degree of fibroblasts in triangular cord of porta hepatis were assessed ： ① juvenile type ： above 50% FBs were juvenile ;② senior type ： above 50% FBs were senior;③median type： between juvenile and senior type. The differentiated degree of FB in porta hepatis were assessed in relation to the liver fibrosis score. SPSS software was used for statistical analysis. Results ①The pathologic changes of early biliary atresia were characterized by inflammation and fibrosis in the hepatic portal area. In control group, mild to moderate degree of bile canaliculus hyperplasia could be seen in pathological slices of limiting plate. The inflammatory reaction and liver fibrous degree were milder than that of the biliary atresia group. Bile canalicular hyperplasia of biliary atresia was more severe and inflammatory reaction was wider than those in control group. Moderate to severe degree of debris necrosis, accompanied by increased liver fibrosis, disappearance of lobular structure, and the formation of numerous pseudo-lobule formation were observed in the biliary atresia group. The fibrosis scores in biliary atresia （ Ⅰ ： 2 cases, Ⅱ ： 12 cases, Ⅲ ： 7 cases） were significantly higher than that in the control group （ Ⅰ ： 8 cases, Ⅱ ： 5 cases, Ⅲ ： 2 cases）. The significant difference was found in the liver fibrosis score between biliary atresia and control group （ P = 0. 01 ）. ②In biliary atresia, all cases of extrahepatic biliary system showed triangular cord in porta hepatis. The triangular cord of porta hepatis was characterized by canalicular hyperplasia, atresia or stenosis of the bile ducts, inflammation infiltration, cholestasis, and interstitial fibrosis.③The ultra-structure features of biliary atresia included activation of FB, loss of microvilli, dense deposit in hepatocytes and liver sinusoid, and canalicular dilatation. ④The differentiated degree of FB in triangular cord of porta hepatis were positively correlated to the liver fibrosis score （ P = O. 04 ） in biliary atresia group. It suggested that the differentiation of FB in triangular cord of porta hepatis or in liver could accelerate the progress of hepatic fibrosis and cirrhosis. Conclusions The main pathologic changes of biliary atresia were inflammation and fibrosis in the hepatic portal area. The ultra-structure features of biliary atresia suggested that the differentiated degree of FB in triangular cord of porta hepatis were positively correlated to the liver fibrosis score.