Amylase levels in bile in patients with a morphologically normal pancreaticobiliary ductal arrangement.

We investigated the presence of occult pancreaticobiliary reflux in patients with a morphologically normal pancreaticobiliary ductal arrangement by measuring biliary amylase levels and compared histopathological findings of the gallbladder between groups with high and low biliary amylase levels. In 178 patients with a normal pancreaticobiliary ductal arrangement who had undergone endoscopic retrograde cholangiopancreatography (ERCP), we sampled bile from the bile duct and measured amylase levels. Then we compared clinical features and histological findings of the gallbladder between high (HALG) and low amylase level groups (LALG). A high biliary amylase level was observed in 25.8% (46/178) of the patients. The prevalence of a high biliary amylase level was high in patients with gallbladder carcinoma (40%) and in those with choledocholithiasis (28.4%). The level of amylase in bile was high in patients with gallbladder carcinoma, adenomyomatosis of the gallbladder, and chronic cholecystitis. A strong correlation between the levels of amylase and lipase in bile and the dominance of amylase of pancreatic origin in bile were confirmed by isozyme analysis. Thickening of the gallbladder mucosa was a significant manifestation in HALG. Histological examination of the gallbladder mucosa showed that incidences of metaplastic change and atypical epithelium and Ki67-LI in were higher in HALG than in LALG. Occult pancreaticobiliary reflux is observed in a considerable number of ERCP candidates. Those who show an extremely high biliary amylase level, at least, may be at high risk for biliary malignancies. [ABSTRACT FROM AUTHOR]