A pancreatic pseudocyst is a circumscribed collection of fluid rich in pancreatic enzymes, blood, and necrotic tissue, typically located in the lesser sac of the abdomen.
Pancreatic pseudocysts are usually complications of pancreatitis, although in children they frequently occur following abdominal trauma. Pancreatic pseudocysts account for approximately 75% of all pancreatic masses. The prefix pseudo- (Greek for "false") distinguishes them from true cysts, which are lined by epithelium; pseudocysts are lined with granulation tissue.
Acute pancreatitis results, amongst other things, in the disruption of pancreatic parenchyma and the ductal system. This results in extravasation of pancreatic enzymes which in turn digest the adjoining tissues. This results in a collection of fluid containing pancreatic enzymes, hemolysed blood and necrotic debris around the pancreas.
The lesser sac being a potential space, the fluid collects here preferentially. This is called an acute pancreatic collection. Some of these collections resolve on their own as the patient recovers from the acute episode. However, others become more organized and get walled-off within a thick wall of granulation tissue and fibrosis. This takes several weeks to occur and results in a pancreatic pseudocyst.
A small pseudocyst that is not causing any symptoms may be managed conservatively. However, a large proportion of them will need some form of treatment, The interventions available are:
- Endoscopic trans-gastric drainage
- Imaging guided percutaneous drainage
- Laparoscopic/open cystogastrostomy or cystojejunostomy
Complication of pancreatic pseudocyst include infection, hemorrhage, obstruction and rupture. For obstruction, it can cause compression in the GI tract from the stomach to colon, compression in urinary system, biliary system, and arteriovenous system.