Follicular cholecystitis: clinicopathologic associations.

Follicular cholecystitis (FC) is a relatively rare entity with uncertain causal associations. In this study, we aimed to explore different clinicopathologic associations of FC, and to better characterize the entity. A retrospective review of archival hematoxylin and eosin slides and pertinent clinical information was undertaken for all cholecystectomy cases with a rendered diagnosis of "follicular cholecystitis," from 1991 to 2017. Concurrent conventional chronic cholecystitis (CC) and lymphocytic cholecystitis (LC) were documented. Forty-three consecutive patients were confirmed to have FC. The majority of the patients (88.4%) had at least one other histologic association in the gallbladder (LC, CC, or both). Remarkably, functional distal biliary obstruction (from choledocholithiasis, sclerosing cholangitis, distal biliary strictures, or malignancies of the pancreatic head or ampulla) was found in 76.7% of the patients, irrespective of the presence of other concurrent histologic findings. FC associated with CC was relatively more common in females (61%) and strongly associated with cholelithiasis (70%). However, those without CC were predominantly males (70%) and had a significant association with LC (75%). All four cases of FC without any other histologic associations who had clinical information available showed some form of distal biliary obstruction. FC cases without concurrent LC were often associated with CC (74%). FC is strongly associated with extrahepatic biliary obstruction distal to the gallbladder. Therefore, this finding at routine cholecystectomy may warrant further evaluation to rule out a cause for distal biliary tract obstruction. Additionally, it is commonly associated with other concomitant histologic abnormalities in the gallbladder such as CC and/or LC.