Biliary Cystadenoma in a Rabbit (Oryctolagus cuniculus)

Biliary tumors are rarely diagnosed in rabbits, and there are very few published case reports of this disease within this group of animals. This case involves an approximately 6-year-old spayed female pet rabbit that was referred for an abdominal mass noted on survey full-body radiographs obtained during an examination after presenting for acute onset anorexia. Otherwise, the patient had an unremarkable history, and physical examination abnormalities were limited to a slightly distended abdomen. Laboratory evaluation revealed an isolated elevation in gamma-glutamyl transpeptidase. Ultrasonography documented a 5.4-cm multicystic, intrahepatic mass with hyperechoic septations. The mass was surgically resected and described histopathologically as a proliferation of ectatic duct structures with a simple epithelial lining, supporting a diagnosis of biliary cystadenoma. The rabbit recovered without incident and was doing well 15 months postsurgery. The case is presented with a review of all reported cases and discussion of the potential origins of this unusual tumor in the rabbit. Surgery is recommended in rabbits that are diagnosed with a biliary tumor.