title: Primary aorto-enteric fistula.
abstract: BACKGROUND
  Primary aorto-enteric fistula (PAEF) is a life threatening, spontaneous erosion and communication of the aorta and intestinal tract. Unlike secondary AEF, which occur following aortic surgery, they are extremely rare. The low clinical suspicion and difficulty in obtaining a definitive diagnosis make for a dismal prognosis.
  
  
  METHODS
  A literature review highlighted aetiology which included gallstone erosion, carcinoma of the pancreas and duodenal diverticulum. With written consent, we present the case of a 59 year old female, brought to the hospital following an episode of haematemesis and later found to have an AEF, secondary to metastatic retroperitoneal carcinoma - an extremely rare aetiology.
  
  
  CONCLUSIONS
  There is far less literature on primary AEF when compared to secondary AEF. Furthermore, there is a variation in aetiology. Identifying the presence of a 'herald' bleed appears to be significant.
  
  
  CONCLUSIONS
  Aorto-enteric fistulae must always be considered as a potential diagnosis in the setting of an acute upper GI haemorrhage with no apparent cause.
authors.affiliation: Croydon University Hospital, London, United Kingdom. Electronic address: andrewg2910@googlemail.com.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Gordon
authors.affiliation: Croydon University Hospital, London, United Kingdom.
authors.forename: Mayank
authors.initials: M
authors.lastname: Agarwal
keywords: Aorto-duodenal fistula; Gastrointestinal haemorrhage; Retroperitoneal metastasis