|Classification and external resources|
A pancreatic pseudocyst as seen on CT
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.
The questions that need to be answered are:
- where, how big and how many?
- is there a communication with the pancreatic ductal system? Draining such a pseudocyst carries an increased risk of pancreatic fistula.
- what are the percentages of pseudocyst forming in chronic pancreatitis
The most useful imaging tools are
- Ultrasonography - The role of ultrasonography in imaging the pancreas is limited by patient habitus, operator experience and the fact that the pancreas lies behind the stomach (and so a gas-filled stomach will obscure the pancreas).
- Computerized tomography - This is the gold standard for initial assessment and follow-up
- Magnetic resonance cholangiopancreatography (MRCP) - to establish the relationship of the pseudocyst to the pancreatic ducts
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 majority of patients who require treatment for their pseudocysts are treated by surgery.
In the surgical procedure for the treatment of pseudocyst a connection is created between the cyst and an adjacent intestinal organ to which the cyst is adherent to such as the stomach. This connection allows the cyst to drain into the stomach. Since in many patients the cyst is formed by continuous leakage of pancreatic juice into the cyst this allows the pancreatic juice to be rerouted into the intestine through the connection.
- Cystgastrostomy: In this surgical procedure a connection is created between the back wall of the stomach and the cyst such that the cyst drains into the stomach.
- Cystjejunostomy: In this procedure a connection is created between the cyst and the small intestine so that the cyst fluid directly into the small intestine.
- Cystduodenostomy: In this procedure a connection is created between the duodenum (the first part of the intestine) and the cyst to allow drainage of the cyst content into duodenum.
The type of surgical procedure depends on the location of the cyst. For cysts that occur in the body and tail of the pancreas either a cystjejunostomy or cystgastrostomy is performed depending on the location of the cyst in the abdomen. For pseudocysts that occur in the head of the pancreas a cystduodenostomy is usually performed.
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.
- Habashi S, Draganov PV (January 2009). "Pancreatic pseudocyst". World J. Gastroenterol. 15 (1): 38–47. doi:10.3748/wjg.15.38. PMC 2653285. PMID 19115466.
- Aghdassi AA, Mayerle J, Kraft M, Sielenkämper AW, Heidecke CD, Lerch MM (2006). "Pancreatic pseudocysts - when and how to treat?". HPB (Oxford) 8 (6): 432–41. doi:10.1080/13651820600748012. PMC 2020756. PMID 18333098.
- Aghdassi A, Mayerle J, Kraft M, Sielenkämper AW, Heidecke CD, Lerch MM (March 2008). "Diagnosis and treatment of pancreatic pseudocysts in chronic pancreatitis". Pancreas 36 (2): 105–12. doi:10.1097/MPA.0b013e31815a8887. PMID 18376299.