Previous studies of gallbladder pathology in primary sclerosing cholangitis (PSC) have suggested that a distinctive histologic triad ("diffuse lymphoplasmacytic acalculous cholecystitis," composed of diffuse, mucosal-based, dense lymphoplasmacytic infiltrates) is commonly present in gallbladders of patients with PSC and is relatively specific for that disease. However, prior control populations have included only patients with cholecystitis/cholelithiasis and hepatitis, and have not evaluated patients with non-PSC-associated extrahepatic biliary tract disease. We recently observed cases of diffuse lymphoplasmacytic chronic cholecystitis in a subset of patients with biliary tract disease associated with lymphoplasmacytic sclerosing pancreatitis and among patients undergoing Whipple resection for pancreatic head malignancy, suggesting that diffuse lymphoplasmacytic chronic cholecystitis is not specific for PSC. We studied 20 gallbladders from patients with obstructive jaundice due to malignancies of the pancreatic head, duodenum, or ampulla and 5 gallbladders from patients with choledocholithiasis, and compared them with 20 gallbladders from patients with PSC and 20 gallbladders with cholelithiasis. The following histologic features were evaluated: degree of mucosal and deep inflammation, lymphoid nodules, epithelial metaplasia, muscular hypertrophy, Rokitansky-Aschoff sinuses, fibrosis, and cholesterolosis. Gallbladders in malignancy-associated obstructive jaundice were nearly identical to gallbladders in PSC with respect to scores for mucosal inflammation, lymphoid nodules, and frequency of diffuse lymphoplasmacytic chronic cholecystitis (60% vs. 50%, respectively). PSC gallbladders, however, were significantly more likely to contain focal or extensive epithelial metaplasia (P = 0.01). The cholelithiasis control group was characterized by lack of significant mucosal inflammation in the majority of cases (95%) and frequent Rokitansky-Aschoff sinuses, fibrosis, and muscular hypertrophy. Gallbladders in the choledocholithiasis group showed overlapping histologic features with PSC/malignancy-associated obstructive jaundice and cholelithiasis. These results suggest that a pattern of diffuse lymphoplasmacytic chronic cholecystitis is highly specific for extrahepatic biliary tract disease but does not distinguish between primary and secondary cholangiopathies.