Microscopic Hepatic Arteriovenous Fistulae and Primary Hypoplasia of the Portal Vein in a Dog

Abstract

An eleven-month-old male Chihuahua was brought to us with intermittent vomiting and diarrhea. Clinicopathological findings showed elevated activity levels of serum liver enzyme and high serum bile acid levels. Ultrasonography detected ascites and increased blood flow in a swollen right medial liver lobe, and laparoscopy revealed acquired portosystemic collateral vessels. These findings strongly suggested the presence of hepatic arteriovenous fistulae, but we could not observe them macroscopically at laparotomy. Histopathologically, however, an autopsy showed typical hepatic arteriovenous fistulae in the right medial lobe, and primary hypoplasia of the portal vein in the other liver lobes.