Congenital Absence of Portal Vein (Abernethy Malformation): A Histopathologic Evaluation.
Mikhail Lisovsky, Angelos A Konstas, Peter F Hahn, Joseph Misdraji. Dartmouth Hitchcock Medical Center, Lebanon, NH; Massachusetts General Hospital, Boston
Background: Congenital absence of the portal vein, or Abernethy malformation, is a rare malformation in which intestinal and splenic venous blood bypasses the liver and drains into systemic veins. Aside from the absence of portal veins, other histologic features of Abernethy malformation have not been emphasized in the literature. The goal of this study was to detail the liver morphologic changes in 5 patients with Abernethy malformation.
Design: Paraffin-embedded tissue sections from two liver biopsies, two liver tumor resections and one liver explant were evaluated using hematoxylin and eosin stains, elastic and trichrome stains. To identify lymphatic vessels immunohistochemistry for D2-40 was performed according to standard protocols.
Results: There were 2 pediatric and 3 adult patients (3 males, 2 females) ranging in age from 17 months to 53 years. One pediatric patient presented with hepatopulmonary syndrome and the other was diagnosed on postnatal ultrasound. One adult female presented with pulmonary hypertension and two adult males presented with hepatocellular carcinoma (HCC). Small portal veins were absent or rare in all patients. Delicate vascular structures at the edges of some portal tracts proved to be lymphatic channels by D2-40 immunostaining. Medium sized portal tracts in resection specimens and the explant showed absence of portal veins in the majority of portal tracts, but in 2 cases, some portal tracts contained hypoplastic portal veins with small caliber lumina and thickened walls. Naked arterioles were noted in the lobules in all cases, sometimes just outside the portal tracts. In 2 cases hepatic artery branches were abnormally large relative to the paired bile duct. Both resection specimens and the explant showed convergence and crowding of portal tracts indicating a remodeling of liver architecture. Two adult patients had HCC in the absence of cirrhosis. Two patients, one with HCC and one child, had focal nodular hyperplasia.
Conclusions: We conclude that in addition to loss of small portal veins, Abernethy malformation is characterized by multiple vascular abnormalities, such as hypoplastic portal veins, naked lobular arterioles, hypertrophy of hepatic artery branches and global remodeling of the liver architecture. Abernethy malformation can be associated with focal nodular hyperplasia and, in some cases, HCC in the absence of cirrhosis.
Category: Liver & Pancreas
Wednesday, March 2, 2011 9:30 AM
Poster Session V # 183, Wednesday Morning