The perinatal transition of the hepatobiliary cyst size provides information about the condition of bile flow in biliary cystic malformation cases.

Abstract Purpose The aim of this study was to understand the level of bile flow by perinatal transitions of the hepatobiliary cyst size in biliary cystic malformation (BCM) cases and to examine the association between the transitions of the cyst size, cholangiographic images of the intrahepatic bile ducts (IHBDs), and histological features of the liver specimens in BCM. Methods We measured perinatal size of the hepatobiliary cyst in 7 BCM cases, composed of 1 case with choledochal cyst and 6 cases with biliary atresia (BA). Bile excretion was inferred from the transition of cyst size and the postoperative course. The IHBD cholangiographic images were also examined. In addition, histology of liver specimens obtained at the time of initial surgery was evaluated for IHBD maturity and fibrosis. Results The size of the small cyst in 2 BA cases remained almost unchanged throughout gestation. These cases required longer postoperative period for the clearance of jaundice. Their IHBD images were indistinct, and histology showed severe fibrosis. The ratio of bile ducts to portal tracts was 0.5 in 1 of the cases. However, in other BCM cases where the cysts grew large perinatally, bile excretion was good postoperatively, and their jaundice cleared in shorter period. Their cholangiographic images demonstrated clearer periphery of the IHBDs, and their histology showed mild or moderate fibrosis, if any. Conclusions The perinatal transition of the cyst size in BCM cases can be helpful in assessing the level of bile flow. BCM with a small cyst during gestation can include some BAs with poorer bile flow, vaguer IHBD images, and prominent liver fibrosis. For the treatment of BCM cases, especially patients with a small biliary cyst, prompt response may be required after birth.