Teaching Case

A cholecystectomized 46-year-old male patient presented at the Emergency Department of our hospital with abdominal pain, general sickness and nausea without fever. The blood test revealed leukocytosis and a normal amylase range.

A double-phase contrast-enhanced 64-MD-CT abdominal study was performed. In the arterial phase around the pancreatic head, uncinate process and tail, a complex hypervascular structure was shown, consisting of ectatic vessels. An early portal vein opacification was also observed.

Other findings were a non-enhancing pancreatic body and tail related to parenchymal necrosis and several fluid collections in pancreatic tail, gastrosplenic ligament and anterior pararenal space; all of them related to associated acute necrotizing pancreatitis with a severity index of 8/10 (according to Mortele’s CT severity index in acute pancreatitis). As a consequence of the inflammatory process, the patient developed splenic vein stenosis and subsequent splenic infarctions.

The angiography confirmed a complex vascular network with tributary branches from the pancreaticoduodenal and gastroduodenal arteries in the pancreatic head/uncinate process and from splenic artery in the pancreatic tail area. Some of them were embolized before the patient underwent a total pancreatomy, splenectomy and duodenal resection.

Pancreatic arteriovenous malformation (PAVM) is a rare entity constituted by an aberrant anastomosis between the arterial and venous system in the pancreas. It can have a congenital origin, such as in Rendu-Osler-Weber syndrome or an acquired one, as a result of inflammatory, tumoral or traumatic causes [1-4]. Our patient had no history of any of the acquired causes.

Most patients with PAVM are asymptomatic. However, some patients suffer a wide range of symptoms, from gastrointestinal bleeding, abdominal pain to jaundice [1]. The relationship between PAVM and acute pancreatitis is not yet fully understood [1].

In spite of the fact that the definitive diagnosis is performed with angiography, MD-CT can be useful in the diagnosis of PAVM and its anatomical relationship with adjacent structures [3]. The typical CT findings include multiple intrapancreatic vessels evidenced in arterial phase like hypervascular tubular images in association with early portal vein enhancement [2, 4]. Reformatted MIP (maximum intensity projection) and volume rendered images are very helpful to identify tributary arteries and efferent veins [3, 4].

Angiography is not only the gold standard diagnostic imaging test for PAVM, (as it provides a detailed vascular map of all supplying vessels), but it can also be an adjuvant presurgical treatment since arterial embolisation can reduce the haemorrhagic risk during the surgery [4]. Surgical resection is the only curative treatment of PAVM. However, the indication of surgery in asymptomatic PAVM is controverted [1].

In summary, we had the chance of studying a rare case of pancreatic arteriovenous malformation in 46-year-old Spanish man who suffered recurrent acute pancreatitis that was successfully treated with surgery. We believe that PAVM should be taken into consideration as uncommon cause of acute pancreatitis [1].