Practice Essentials
Permanent communication caused by erosion of the pancreatic or peripancreatic artery into a pseudocyst gives rise to a rare but life-threatening complication known as a pancreatic pseudoaneurysm. Pancreatitis with secondary pseudocyst formation is the most common cause of pancreatic pseudoaneurysms, though they have been known to occur in the absence of a pseudocyst.
The literature confirms that differentiating a pseudoaneurysm from a bleeding pseudocyst is difficult.
A pseudoaneurysm differs from a true aneurysm in that its wall does not contain the components of an artery but instead consists of fibrous tissue, which usually continues to enlarge, creating a pulsating hematoma.
Pancreatic pseudoaneurysm should be distinguished from primary peripancreatic vessel aneurysm, which tends to occur more often in women. The rare rupture of a primary aneurysm tends to occur in pregnancy and manifests as massive intraperitoneal bleeding with hemodynamic instability.
Overall, the splenic artery is the most frequent site of visceral artery pseudoaneurysms, followed by the hepatic artery.
Pseudoaneurysm formation may have an incidence as high as 10% in patients with chronic pancreatitis who undergo angiography.
Pancreatic pseudoaneurysms, though rather uncommon, are frequently accompanied by life-threatening complications, mainly rupture and bleeding. Hemorrhage can occur in the pseudocyst itself, via the ampulla of Vater, or by fistulation into nearby hollow organs.
Better outcome requires accurate, timely, and appropriate diagnosis and intervention (medical, surgical, or both). The standard of care in dealing with pancreatic pseudoaneurysms has been surgical intervention. However, owing to advances in the field of interventional radiology, the paradigm has largely shifted toward endovascular treatment of these lesions.