Abstract: Objective To study the pathological basis of congenital biliary dilatation (CBD) with liver injury in children. Methods 138 cases of CBD with liver injury admitted to our hospital from May 2014 to May 2019 were included as the research object, and a retrospective analysis was carried out.According to the age of the children, the children were divided into group A (72 cases aged from 1 month to 3 years) and group B (66 cases aged from 4 to 16 years).The clinical characteristics of the two groups were analyzed, and the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IBIL), alkaline phosphatase (AKP), gamma-glutamyltransferase (GGT), albumin (ALB) were compared. The levels of serum amylase, urine amylase, bile amylase, platelet count, leukocyte count and hemoglobin were observed. Results In group A, cystic dilatation of common bile duct was dominant, cyst diameter was larger, most distal cysts were strictured and atresia, and cysts were accompanied by protein embolus, calculi, hepatomegaly and cholestasis;Group B was dominated by spindle dilatation, with most of the cysts opening at the distal end and relatively small cyst diameter, a few cysts with obvious stenosis and atresia at the distal end, and a few with large liver and obvious cholestasis.The incidence of jaundice and pottery stool in group A was 68.1% and 72.2% respectively, which was significantly higher than that in group B (18.2% and 15.2% (P<0.05), and the incidence of abdominal pain was 38.9%, which was significantly lower than that in group B (95.5% (P<0.05);The incidence of fever, abdominal distension, vomiting, abdominal mass and hepatosplenomegaly in group A was not significantly different from that in group B (P>0.05).ALT, AST, TBIL, DBIL, AKP, GGT in group A were significantly higher than those in group B (P<0.05), while IBIL and ALB were not significantly different from group B (P>0.05).White blood cell count in group A was significantly higher than that in group B (P<0.05), and bile amylase was significantly lower than that in group B (P<0.05), and there were no statistically significant differences in blood amylase, urine amylase, hemoglobin and RBC count between groups B (P>05). Conclusion Children with CBD at different ages have different clinical manifestations, accompanied by different degrees of liver injury. Biliary obstruction and cholestasis are the pathological basis of liver injury in children, which should be paid enough attention to clinically.

Key words: Children, Congenital cholangiectasis, Liver injury, Pathology