Early mucosal changes of the gallbladder in patients with anomalous arrangement of the pancreaticobiliary duct

Background & Aims: Anomalous arrangement of the pancreaticobiliary duct (AAPBD) is frequently associated with gallbladder cancer. The aim of this study was to characterize the early epithelial changes of the gallbladder that might be associated with carcinogenesis in patients with AAPBD. Methods: Routinely fixed tissue specimens obtained from pediatric patients with AAPBD and control patients were examined histologically with H&E, periodic acid-Schiff, and argyrophilic nucleolar organizer region (AgNOR) staining. Results: Epithelial hyperplasia was frequently observed in the gallbladder of patients with AAPBD but not in patients without this anomaly. The incidence of epithelial hyperplasia was significantly higher in the gallbladder of patients in whom the major pancreatic duct joined the common bile duct (P-C type) than in patients in whom the common bile duct joined the pancreatic duct (C-P type). The mean AgNOR number in the gallbladder mucosa was significantly higher in patients with AAPBD than in patients without AAPBD. Patients with P-C type AAPBD had a significantly higher mean AgNOR number of the gallbladder mucosa than patients with C-P type AAPBD. Conclusions: Patients with AAPBD, especially those with the P-C type anomaly, have increased cellular proliferative activity of the gallbladder mucosa in early childhood.