Abernethy malformation

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-side shunt; superior mesenteric and splenic vein drain separately into inferior vena cava
  • type II: side-to-side shunts; superior mesenteric vein and splenic vein form a common trunk before draining into the inferior vena cava

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.

Hepatobiliary pathology

Article information

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

ADVERTISEMENT: Supporters see fewers/no ads

Cases and figures

  • Case 1: CT
    Drag here to reorder.
  • Case 1: DSA
    Drag here to reorder.
  • Case 2: CT
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.