Gallbladder adenoma in a domestic shorthair cat

A 13-year-old neutered female domestic shorthair rescue cat presented asymptomatically with raised hepatic enzymes following a routine pre-anaesthetic blood test. Cholangitis was suspected, and supportive treatment with 2 weeks of amoxicillin-clavulanic acid and 4 weeks of ursodeoxycholic acid and S-adenosylmethionine was trialled, with no improvement in biochemistry parameters. Clinicopathological investigations also revealed a markedly raised total bilirubin and abnormal bile acid stimulation test. Abdominal ultrasonography revealed pathological changes in the gallbladder, hepatomegaly with increased echogenicity and markedly thickened common bile duct walls. An exploratory laparotomy was performed revealing a grossly abnormal gallbladder with a small rupture at the dorsal fundus, which was managed via cholecystectomy. Pancreatic and hepatic biopsies were collected concurrently. Histopathology from the submitted samples revealed a gallbladder adenoma, chronic neutrophilic cholangitis and nodular hyperplasia of the pancreas. Culture of the gallbladder bile was negative but may be attributable to the initial treatment with antibiosis. At the time of writing, 5 months postoperatively, the cat had recovered well and remained asymptomatic and clinically healthy, but hepatic enzymes and bilirubin were only mildly reduced from the preoperative levels, despite the cat remaining clinically normal.

Relevance and novel information: To our knowledge, this is the first case of a gallbladder adenoma confirmed histopathologically in a feline patient. Our findings suggest that although gallbladder neoplasia is rare in cats, this benign tumour should be considered a differential diagnosis.