LESIONS WITH A HIGH RISK OF CARCINOGENESIS IN THE GALLBLADDER OF PATIENTS WITH A LONG COMMON CHANNEL

Background:  Pancreaticobiliary maljunction (PBM) is characterized by a markedly long common channel. In this condition, the sphincter of Oddi does not functionally affect the junction of the pancreatic and bile ducts. Reflux of pancreatic juice into the biliary duct of patients with PBM occurs, resulting in a high incidence of carcinogenesis in the gallbladder. Hence, the gallbladder mucosa of PBM appears to be in a precancerous state. However, the relationship between a relatively long common channel and precancerous lesions of the gallbladder is unknown. The present study aimed to investigate histopathological changes in the gallbladder of patients with a relatively long common channel. Methods:  High confluence of pancreaticobiliary ducts (HCPBD) was defined as presence of a common channel ≥ 6 mm in which communication between the pancreatic and bile ducts was disrupted with sphincter contraction. We histopathologically examined the resected or autopsied gallbladder specimens from patients with HCPBD (n = 20), PBM without biliary dilatation (n = 15) and controls (n = 10); focusing on mucosal height and hyperplastic change. Proliferation activity was also examined with Ki-67 immunostaining. Results:  The gallbladder mucosa was significantly higher in PBM and HCPBD than in controls. Hyperplastic mucosal changes were detected more frequently in PBM (73.3%, P < 0.01 vs controls) and in HCPBD (45.0%, P < 0.05 vs controls). Ki-67 labeling index of the gallbladder epithelium was significantly higher in both PBM and HCPBD than in controls (P < 0.01). Conclusions:  In HCPBD, the gallbladder mucosa displayed hyperplastic changes with increased cellular kinetics and appeared precancerous, with a similar appearance to that in PBM.