Gallbladder mucocele, a cyst or cavity accompanied by mucus accumulation in the gallbladder, was rarely reported in dogs before the early 1990s and seems to be on the rise, possibly because of nutritional factors, environmental factors, or improved sono-graphic detection. Medical management using antimicrobials and choleretics has a poor prognosis, and gallbladder rupture is common. This retrospective study investigated the clinical, clinicopathologic, ultrasonographic, microbiologic, and histologic findings as well as the long-term response to cholecystectomy in dogs with gallbladder mucocele. Sensitivity of sonography for detection of rupture was 85.7%. The authors' hypothesis is that surgical removal of the gallbladder is an appropriate treatment and that the long-term outcome is good. Medical records of 30 dogs with gallbladder mucocele were reviewed. Twenty-three dogs had signs of illness, 7 did not, and 3 of the dogs with known mucoceles did not respond to medical management. Of the 23 dogs that underwent cholecystectomy, the perioperative mortality rate was 21.7% and was not significantly greater for dogs with ruptures. Aerobic bacteria were isolated from the bile or gallbladder wall in only 8.7% of the dogs. All 18 dogs discharged from the hospital had complete resolution of clinical signs, and dogs reexamined in the hospital had significantly reduced serum liver enzyme activity (mean follow-up, 13.9 months). The cause of gallbladder mucocele is unknown, but the current results do not support an inflammatory or bacterial cause. A consistent finding of mucosal hyperplasia suggests that the gallbladder itself is diseased. Cholecystectomy proved to be an effective treatment with a good prognosis, even though the perioperative mortality rate was high. Rupture of the gallbladder warrants emergency surgical intervention, but prognosis after discharge from the hospital is excellent.

COMMENTARY: Considering the underlying pathology of gallbladder mucocele, medical management is unlikely to be efficacious and surgical intervention should be done as expeditiously as possible before rupture occurs. Even though not statistically significant (possibly related to sample size, as pointed out by the authors), surgical intervention before gallbladder rupture was associated with a lower mortality rate (approximately 11% without rupture versus 29% with rupture). Cholecystectomy is a fairly straightforward procedure, especially when the gallbladder has not ruptured, but care must be taken to ensure that the cystic duct and any adjacent hepatic ducts that are damaged during dissection are securely ligated. In this study, cholecystectomy was shown to be an effective treatment for gallbladder mucocele, although 2 patients requiring reoperation for leakage died.

Gallbladder mucocele in dogs: 30 cases (2000-2002). Pike FS, Berg J, King NW, et al. JAVMA 224:1615-1622, 2004.