Abernethy malformation

Dr Henry Knipe and Dr Yuranga Weerakkody et al.

Abernethy malformations are rare vascular anomalies of the splanchnic venous system. They consist of congenital portosystemic shunts and result from persistence of the embryonic vessels. 

Type I malformations are thought to occur only in females, while type II have a male predominance 1.

There are two main types of Abernethy malformations that have been described (initially devised by G Morgan and R Superina 6):

  • type I: end-to-end shunts
  • type II: side-to-side shunts

In type I shunts (end-to-end), there is a congenital absence of the portal vein with a complete diversion of portal blood into systemic veins (inferior vena cava, renal veins, or iliac veins). These are further subdivided into:

  • type Ia: separate drainage of the superior mesenteric vein and splenic vein into systemic veins
  • type Ib: superior mesenteric vein and splenic vein join to form a short extra-hepatic portal vein which drains into a systemic vein (inferior vena cava, right atrium or iliac veins)

In type II shunts (side-to-side), there is a hypoplastic portal vein with portal blood diversion into the inferior vena cava through a side-to-side, extrahepatic communication.

Named after John Abernethy, who gave the first account of an absent portal vein with accompanying congenital mesentericocaval shunt 1,5 in 1793.

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Article information

rID: 17836
Tag: cases
Synonyms or Alternate Spellings:
  • Abernethy's malformation
  • Congenital absence of the portal vein
  • Congenitally absent portal vein
  • Congenital extrahepatic portosystemic shunt

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Cases and figures

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    Case 1: CT
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    Case 1: DSA
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    Case 2: CT
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