Embryogenesis of pancreaticobiliary maljunction inferred from development of duodenal atresia

Abstract

The embryogenesis of pancreaticobiliary maljunction is inferred from the embryogenesis of duodenal atresia. The epithelial cells of the duodenum begin to proliferate and completely plug the lumen, but a process of vacuolation recanalizes the duodenum. Recanalization of the common duct frequently appears with two lumina and openings into the duodenum with two orifices. These two major canals create a narrow segment of the duodenum and this narrow zone is the area in the duodenum that is most prone to faulty recanalization and atresia formation. A bifid biliary system inserts at blind upper and lower pouches of the duodenum, and the common bile duct inserts in a Y fashion. The common bile duct inserts at the stenotic segment, and the end result is a T-shaped formation in patients with duodenal stenosis. During the development of the bile duct, abnormal fusion may occur between the bile duct and branches of the right ventral pancreatic duct. The site in the bile duct where a branch of the pancreatic duct joins is likely to develop atresia due to disturbance of the recanalization process, as seen in duodenal atresia. Severe impairment of vacuolation causes divided atretic bile duct at the site where the pancreatic duct inserts in a Y-fashion into the upper and lower bile duct. Moderate impairment of vacuolation causes a stenosis at the site where the pancreatic duct inserts in a T-shape, with a moderate dilatation of the bile duct.

Anatomical variations of liver blood supply in patients with pancreaticobiliary maljunction

“…AP and PD are both abnormal fusions of the ventral and dorsal pancreas, and the pathogenesis of DCBD is in the process of the formation of the common bile duct. Thus, AP, PD, DCBD, and PBM are developed during similar periods and are potentially concomitant [1,2,40]. However, to date, no report has described the vascular anatomy in patients with this deformity.…”

“…Its prevalence in Japan is estimated at about 0.1 % [1]. PBM is thought to occur as a result of an abnormal fusion of the ventral pancreatic duct with the bile duct in the 4-5th gestational week [1,2]. The major clinical feature of PBM is biliopancreatic reflux, which triggers chronic inflammation of the biliary tract and the later development of biliary tract cancer [3][4][5][6][7][8].…”

Foregut atresias and bile duct anomalies: rare, infrequent or common?!

“…It is hypothesised that pancreato-biliary malunion develops as part of the spectrum of the defective embryogenesis that leads to DA. Pancreato-biliary reflux then affects the mesoderm of the developing bile ducts progressing to weakness, thinning and asymmetric dilatation of the bile duct that becomes a choledochal cyst [9,11,12]. A familial type of DA has been reported (Feingold syndrome); but this does not affect the developing bile ducts [13,14].…”

Japanese clinical practice guidelines for pancreaticobiliary maljunction

“…The abnormal dilatation of the biliary tree is thought to occur in the common bile duct, cystic duct, and gallbladder (all of which originate from the hepatic diverticulum), as well as in the hepatic duct (which originates from the hepatic diverticular epithelia) when the continuity between the hepatic diverticular epithelia and that of the primitive gut is lost [6]. Various hypotheses [7][8][9] exist regarding the developmental mechanisms underlying PBM, and opinion is also divided on how the pancreas and the biliary tract develop.…”