Histopathological distinction and evaluation of biliary and peribiliary cysts in pig liver

The majority of hepatic cysts identified in animals are considered to derive from the intrahepatic bile ducts (biliary cysts). An alternative origin is the peribiliary glands located in the hilum of the liver and large portal tracts (peribiliary cysts). The distinction between biliary and peribiliary cysts, and whether these have different clinical significance, has rarely been considered previously. This study reports the pathological features of five cystic porcine livers. Four of these five livers had both biliary and peribiliary cysts and the fifth had only biliary cysts. Biliary cysts were not associated with distortion of adjacent hepatic parenchyma, whereas peribiliary cysts appeared to cause local compression and circulatory disturbance. It would therefore appear that peribiliary cysts have greater potential clinical significance than those of biliary origin.