Biloma in a cat with cholelithiasis and suspected previous biliary peritonitis due to gallbladder rupture

Case summary: A 14-year-old, female spayed domestic shorthair cat presented with a 2-day history of lethargy and intermittent vomiting. Abdominal ultrasonography identified biliary obstruction with several choleliths, dilation and thickening of the intrahepatic biliary ducts and a mass-like lesion was identified in the right medial liver lobe, attached to the gallbladder. Cholecystectomy and partial liver lobectomy were performed to treat biliary obstruction and remove the mass lesion, respectively. Histopathological examination of the hepatic mass confirmed the diagnosis of biloma. Relevance and novel information: Bilomas and biliary pseudocysts are considered uncommon findings in cats. This is the first reported case of spontaneous biloma in a cat associated with biliary obstruction secondary to cholelithiasis and presumptive previous history of biliary peritonitis. Non-iatrogenic causes, such as gallbladder rupture, should be considered in the differential diagnosis of feline biloma.