Polycystic liver in two adult llamas.

Polycystic liver is usually considered an incidental finding in human and veterinary medicine. Two unrelated adult llamas ( Lama glama) with a history of marked anorexia and weight loss were received for autopsy and diagnostic workup. The main gross change in the liver of both animals was multiple variably sized cysts randomly distributed throughout the parenchyma. Histologically, the cysts compressed the adjacent parenchyma and were lined by a single layer of cuboidal-to-columnar epithelium, surrounded by a fibrous collagen capsule. The lumen of the cysts contained finely granular-to-homogeneous basophilic material. The lining epithelium displayed strong immunoreactivity for pancytokeratin AE1/AE3 and cytokeratins 7, 8, 8/18, and 19, and was negative for vimentin, confirming the biliary epithelial origin of the cysts. No parasitic or infectious agents, or neoplastic changes, were detected. All other laboratory tests performed in both llamas were negative or non-diagnostic, suggesting that the congenital hepatic cysts described may have been at least partly responsible for clinical disease in both animals.