Congenital intrahepatic arteriovenous fistulae in a young beagle dog.

Congenital intrahepatic arteriovenous fistulae, a rare hepatic vascular anomaly, in an 8-mo-old female beagle dog was investigated. The animal showed anorexia, repeated vomiting, hemorrhagic diarrhea, and jaundice for approximately 2 wk. There was mild to severe increase of serum alkaline phosphatase, glutamic-oxalacetic transaminase, glutamic pyruvic transaminase, total cholesterol, total bilirubin, and gamma-glutamyl transpeptidase. Macroscopically, the main abdominal organs showed hemorrhagic edema together with bloody ascites. Other characteristic findings were severe hepatic atrophy (right medial, quadrate, left medial, and lateral lobes) with multiple vascular cysts and compensatory hypertrophy of the other lobes. The cystic vessels seemed to extend from the proper hepatic arteries and their branches but were indistinguishable from the portal vein. Histopathologically, the atrophied hepatic lobes were characterized by wide, fibrous septa containing severe hyperplasia and anastomosis of the arteriolae and venulae and proliferation of bile ducts.