Cholecystosteatosis: an explanation for increased cholecystectomy rates.

INTRODUCTION: Over the past decade, obesity has become epidemic, and the number of cholecystectomies as well as the percentage with acalculous cholecystitis have increased. We have recently reported that congenitally obese mice and lean mice fed a high fat diet have increased gallbladder wall lipids and poor gallbladder emptying. Therefore, we tested the hypothesis that compared to patients with a normal gallbladder, patients with both acalculous and calculous cholecystitis would have increased gallbladder wall fat.

METHODS: Sixteen patients who underwent cholecystectomy for acalculous cholecystitis were identified. Sixteen nondiseased controls who underwent incidental cholecystectomy during surgery for liver or pancreatic disease and 16 diseased controls whose gallbladder was removed for chronic calculous cholecystitis were chosen to match the acalculous patients for gender and Body Mass Index. Pathology specimens were reviewed in a blinded fashion for gallbladder wall fat, thickness, and inflammation.

RESULTS: Acalculous cholecystitis patients were younger (p < 0.01) than nondiseased or diseased controls. Gallbladder wall fat was significantly increased (p < 0.02) in the acalculous and calculous cholecystitis patients compared to the nondiseased controls. Gallbladder wall thickness (p < 0.02) and inflammatory score (p < 0.01) were highest in the calculous cholecystitis patients.

CONCLUSIONS: These data suggest that compared to nondiseased controls, (1) patients with acalculous cholecystitis are younger and have increased gallbladder fat and (2) patients with calculous cholecystitis have increased gallbladder fat and inflammation. We conclude that increased gallbladder fat may lead to poor gallbladder emptying and biliary symptoms. Thus, cholecystosteatosis may explain, in part, the increased need for cholecystectomy and the higher percentage of these patients with acalculous cholecystitis.