Gallbladder mucocele causing biliary obstruction in two dogs: ultrasonographic, scintigraphic, and pathological findings

Abstract

Two dogs were found to have intraluminal gallbladder masses which caused partial or complete extrahepatic biliary obstruction. On histological examination, the gallbladder masses were confirmed to be mucoceles. Gallbladder mucoceles are rare in humans and previously have been described only after gallbladder rupture in two dogs. In the dogs of this report, the biliary obstruction was relieved by cholecystectomy. Each dog also had histological evidence of chronic liver disease with intrahepatic cholestasis. The clinical diagnosis of biliary obstruction was based on scintigraphic and sonographic findings which will be discussed and compared with other hepatobiliary diseases.

Clinical Findings and Prognostic Factors for Dogs Undergoing Cholecystectomy for Gall Bladder Mucocele

“…The latter is a rarely reported consequence of biliary GM. 5 Although successful medical management of 2 non-severe cases of GM was recently reported, 6 cholecystectomy is generally indicated for GM causing biliary tract outflow obstruction. Cholecystectomy often involves flushing of the CBD before cystic duct ligation to ensure patency.…”

“…4 Progressive distension of the gall bladder may eventually cause pressure necrosis of the gall bladder or the bile duct, leading to rupture and subsequent bile peritonitis. 3,5 Obstruction secondary to the accumulated mucus can occur anywhere from the neck of the gall bladder to the extrahepatic biliary tree. The latter is a rarely reported consequence of biliary GM.…”

Liver

“…200,218 The surgical treatment for this disorder has been described in the dog. 219,[223][224][225]227 Clinical signs, although sometimes absent, include abdominal pain, inappetence, fever, vomiting, and icterus. 11,185,[219][220][221] The odds of a biliary mucocele developing in dogs with hyperadrenocorticism are 29 times that of dogs without hyperadrenocorticism.…”

“…225,226 Mucoceles may be associated with extrahepatic biliary obstruction (see Figure 9-48), gallbladder wall necrosis, and perforation (Figure 9-49). 219,[223][224][225][226][227] Exploratory surgery for possible cholecystectomy, with or without lavage of the biliary tree, or cholecystoduodenostomy has been recommended. Cats have fewer mucus-secreting glands in their gallbladder, which may explain why mucoceles do not develop.…”

An insertion mutation in ABCB4 is associated with gallbladder mucocele formation in dogs

“…In particular, gallbladder mucoceles (mucinous hyperplasia or mucinous cholecystitis) have been documented to be an increasingly important cause of hepatobiliary disease in dogs [13-15]. Histopathologic findings associated with ABCB4 associated diseases in people, including intrahepatic cholestasis, cholecystitis, and periportal inflammation [13,16,17], are not commonly reported in dogs with gall bladder mucoceles. Additionally, gallbladder mucoceles are not a component of ABCB4 linked syndromes in people or mice.…”