Pancreatic pseudocysts are abnormal swellings that look like cysts (Figure 1).
They usually happen after new inflammation of the pancreas or injury. Pancreatic pseudocysts make up more than 75% of cystic problems of the pancreas; they are located most often behind the stomach. The wall of the cyst is made of inflammatory tissue which can be flimsy or tough, and the lining lacks the normal cells present in true cysts.
Pancreatic pseudocysts most often develop after an episode of severe, acute pancreatitis. Acute pancreatitis is sudden swelling (inflammation) of the pancreas.
A pancreatic pseudocyst may occur in someone with chronic pancreatitis. It may also occur after trauma to the abdomen, more often in children. Patients often were injured by a blow to the belly or had an illness resembling pancreatitis weeks to months earlier. Upper belly pain and loss of appetite progressing to nausea, vomiting, and weight loss often follow. Eventually one is able to feel a round mass in the upper part of the belly.
Description of Pancreatitis Pseudocysts
These cysts are usually one big cyst, and they can hold more than 1 liter of fluid. 70% of these cysts may result from injuries. Pseudocysts occasionally occur after pancreatitis caused by unknown factors, and rarely a stone stuck in the main bile tube, a duplication cyst, or mumps may cause a pseudocyst to form.
Results of Pseudocysts
The growing pseudocyst may push the stomach up and forward and the colon down and forward. A portion of the first part of the small intestine may be narrowed or blocked. Increased fluid inside the belly may develop with large increases in pancreatic enzyme levels. Abdominal ultrasound and CT are generally diagnostic (Figure 1).
Small cysts not interfering with bowel function often can be followed with repeated ultrasound or CT until they ultimately disappear. For acute pseudocysts resulting from injuries, needle drainage through the skin sometimes is effective. Complications from untreated large pseudocysts may include bleeding, infection, rupture with severe belly pain, and blockage of bowel, pancreatic, or bile tube function.
Treatment of the Pseudocysts
Treatment depends on the size of the pseudocyst and whether it is causing symptoms. Many pseudocysts go away on their own. In fact, of the patients with moderately severe acute pancreatitis, including pancreatitis caused by injuries, who get pseudocysts, 50% go away on their own within 3 to 4 weeks when treated without surgery, unless infection occurs.
Those that remain for more than 6 weeks and are larger than 5 cm in diameter often need treatment.
Possible treatments include:
- Drainage through the skin using a needle, usually guided by a CT scan
- Endoscopic-assisted drainage using an endoscope (a tube containing a camera and a light that is passed down into the stomach)
- Surgical drainage of the pseudocyst, which involves making a connection between the cyst and the stomach or small intestine. This may be done using a laparoscope.
When to Seek Medical Help
- Fever and chills
- Rapid Heartbeat
- Severe abdominal pain
The outcome of pancreatitis pseudocysts is generally good with treatment. It is important to make sure that it is not a pancreatic cancer that starts in a cyst, which has a worse outcome.
Forsmark CE. Pancreatitis. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011: chap 146.
Forsmark Ce, Baillie J. AGA Institute Technical Review on acute pancreatitis. Gastroenterology. 2007; 132: 2022-2044.