Multicentric Intrahepatic Biliary Cystadenoma in a Dog

This report describes a case of multicentric intrahepatic biliary cystadenoma observed in a 13-year-old, male, Irish setter dog. The dog had a history of chronic inappetence, weight loss, intermittent icterus, and diarrhoea. In the ultrasonographic examination of the abdominal organs, 5 spherical masses were found in various liver lobes. The largest mass was 12 cm in diameter and was located on the quadrate lobe. It had spongy consistency and had several cystic structures, 3 mm-2.5 cm in diameter, on the cut surface. While this mass bulged through the normal outline of the liver, smaller masses were engraved within the liver parenchyma. Histopathologically, cystic glandular structures lined by cubical to columnar epithelial cells were observed. Immunohistochemically, tumoural cells stained positively with anti-cytokeratin 7 and anti-cytokeratin 19 antibodies. We report herein a rare case of multicentric biliary cystadenoma in an Irish setter dog with histopathological and immunohistochemical findings.