CHARACTERIZATION OF HEPATOPORTAL MICROVASCULAR DYSPLASIA IN A KINDREDOF CAIRN TERRIERS

Hepatoportal microvascular dysplasia (MVD), a congenital disorder of t he hepatic vasculature, is described in a kindred of Cairn Terrier dog s. Cairn Terrier dogs (n = 165) were evaluated using the serum bile ac id test. Affected dogs, identified by abnormal fasting or postprandial serum bile acid concentrations, were divided into 2 groups. Group 1 d ogs (n = 147) were used for pedigree analysis. Group 2 dogs (n = 18) w ere characterized on the basis of history, physical examination, clini copathologic studies, diagnostic imaging of the liver and portal circu lation, and hepatic histopathology. Group 2 contained control dogs (n = 2), dogs with hepatoportal MVD (n = 11), and dogs with macroscopic p ortosystemic vascular anomalies (PVSA) (n = 5). With the exception of high serum bile acid concentrations, dogs with hepatoportal MVD were i ndistinguishable from control dogs on the basis of history, physical e xamination, clinicopathologic findings, survey abdominal radiography, abdominal ultrasound, or transcolonic scintigraphy. Contrast portograp hy in dogs with MVD revealed abnormalities of terminal twigs of the po rtal vasculature with out large intrahepatic or extrahepatic shunting vessels. Histopathologic abnormalities in dogs with hepatoportal MVD w ere similar to those reported for dogs with PSVA. Pedigree analysis su ggested an autosomal inheritance for MVD. Dogs with MVD had high serum bile acid concentrations, abnormal indocyanine green clearance, and h epatic pathology suggestive of PSVA, but they lacked characteristic cl inical findings of PSVA. The clinical significance of MVD is unclear. Dogs with MVD were clinically normal when evaluated but long-term foll ow-up is not yet available. Dogs with hepatoportal MVD should be ident ified at an early age to avoid confusion in future diagnostic evaluati ons. Copyright (C) 1996 American College of Veterinary Internal Medici ne.