Congenital biliary tract malformation resembling biliary cystadenoma in a captive juvenile African lion (Panthera leo).

A captive 3-mo-old white African lion (Panthera leo) presented with clinical signs of acute pain and a distended abdomen. Despite emergency treatment, the lion died a few hours after presentation. Postmortem examination revealed gross changes in the liver, spleen, and lungs and an anomalous cystic structure in the bile duct. Histologic examination identified severe generalized multifocal to coalescent necrotizing and neutrophilic hepatitis, neutrophilic splenitis, and mild interstitial pneumonia, consistent with bacterial septicemia. The abnormal biliary structures resembled biliary cystadenoma. However, due to the age of the animal, they were presumed to be congenital in origin. Biliary tract anomalies and cystadenomas have been reported previously in adult lions, and this case suggests that at least some of these examples may have a congenital basis. It is unclear whether the lesion was an underlying factor in the development of hepatitis.