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A pancreatic pseudocyst is a benign, fluid-filled mass that develops outside of your pancreas, usually following pancreatitis. It can go away by itself, but sometimes, healthcare providers drain pseudocysts to make them go away.
A pancreatic pseudocyst is a pocket of fluid that develops outside of your pancreas after it’s been injured, usually by pancreatitis. Your pancreas is an organ in your abdomen (belly) that makes enzymes for your digestive system. It delivers these enzymes as fluid to your small intestine through your pancreatic duct.
Pancreatitis is inflammation and swelling in your pancreas. A severe case of pancreatitis can cause your pancreatic duct to leak. When pancreatic juices leak, the digestive enzymes can irritate the surrounding tissues. A protective capsule forms around the leak, made of fibrous, scar-like tissue. This is a pseudocyst.
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A pancreatic pseudocyst isn’t a true cyst because it’s not made of true pancreatic tissue. The capsule is only fibrous scar tissue and doesn’t have the telltale lining of epithelial cells that pancreatic tissue does. Instead, it’s lined with granulation tissue, the type that forms over a wound during the healing process.
A pancreatic pseudocyst is ultimately an inflammatory wound rather than a separate structure. A pancreatic cyst, on the other hand, is a growth in the wall of your pancreas that’s formed from its own tissues. It may contain fluid as well as solid material. Some true cysts have cancerous potential.
Pancreatic pseudocysts aren’t precancerous and usually don’t cause serious complications. They often go away on their own. But if they grow large, there’s a risk they could interfere with nearby organs or blood vessels. Sometimes, they can become infected. In these cases, healthcare providers intervene.
Pseudocysts occur in approximately 35% of people with chronic pancreatitis and 10% of people with acute pancreatitis. They’re the most common type of pancreatic mass, accounting for about 75%. But they’re uncommon overall. They affect approximately 3% of adults each year, and rarely children.
The most common cause is pancreatitis, and the most common cause of pancreatitis resulting in pseudocysts is alcohol use. Alcohol-related pancreatitis accounts for 70% of pancreatic pseudocysts. Gallstone-related pancreatitis is the second leading cause. In children, it’s more likely to be trauma.
Trauma or swelling from pancreatitis can partially block your pancreatic duct or disconnect it from your intestine. This causes some of the pancreatic fluid to leak out into your abdominal cavity. The fluid collects between the walls of your organs, and a capsule forms around it, creating a pseudocyst.
Smaller pseudocysts may not cause any symptoms, but larger ones may be noticeable. They may cause symptoms similar to pancreatitis itself. But they usually develop several weeks after the onset of acute pancreatitis, or after a “flare-up” of chronic pancreatitis that disrupted your pancreatic duct.
Symptoms might include:
Symptoms of complications, if they occur, might include:
Complications are unlikely but possible, including:
Healthcare providers can usually recognize pancreatic pseudocysts on a high-quality imaging test, like a contrast CT scan or MRI. But sometimes, they need to take a sample to distinguish a pseudocyst from another type of mass. They can do this with endoscopic ultrasound and fine needle aspiration.
Endoscopic ultrasound combines endoscopy with ultrasound. A healthcare provider passes a tiny camera on a long tube (endoscope) down your throat and into your small intestine. Then, they pass a smaller tube with an ultrasound wand on the end through the endoscope to visualize your pancreas.
Fine needle aspiration is a type of biopsy procedure. An endoscopist can pass tiny tools through the endoscope to perform minor procedures, including biopsy. They can pass a fine, hollow needle through to take fluid and tissue samples of the pseudocyst. They’ll send these samples to a lab to analyze.
Your pancreas is roughly fish-shaped, with a head, body and tail. About two-thirds of pseudocysts occur at the tail, and one-third at the head. Pseudocysts are roundish and smooth, with well-defined walls and filled with clear, watery fluid. They vary in size from 2 to 30 centimeters in diameter. You might have one or several.
Many pancreatic pseudocysts resolve on their own with time. Healthcare providers monitor them while offering supportive care, such as:
When pseudocysts don’t go away or show signs of complications, healthcare providers intervene.
Healthcare providers intervene when pseudocysts last longer than six weeks. About one-third of them will go away on their own during this time. They may be less likely to resolve on their own if you have multiple pseudocysts or if you have long-term complications from chronic pancreatitis, like scarring.
Healthcare providers drain pseudocysts to make them go away. They can do this in a few different ways. Endoscopic drainage is usually the first choice, although certain cases might call for other methods, like surgery. Endoscopic drainage is less invasive and has similar long-term success rates to surgery.
The standard procedure is called a cystogastrostomy, which means creating a connection between the pseudocyst and your stomach for the pseudocyst to drain into. Depending on where the pseudocyst is located, it might be a connection to your small intestine instead, or even your pancreatic duct.
Your stomach and small intestine are well-equipped to process the fluid from the pseudocyst. Both have a protective lining that insulates them from digestive enzymes and acids. (Your small intestine is where pancreatic fluids are usually delivered.) Once the fluid has been drained, the capsule will dissolve.
Treatment for a pancreatic pseudocyst will require a brief hospital stay and a follow-up procedure several weeks later to remove the stents or drainage tubes they used to keep the cystogastrostomy open. The success rate of drainage procedures is over 90%. Occasionally, pseudocysts come back.
See a healthcare provider if you have symptoms of pancreatitis: Abdominal pain that spreads to your back, combined with nausea and/or vomiting. If you’ve recently been treated for pancreatitis and you develop symptoms again four to six weeks later, you might have developed a pancreatic pseudocyst.
Pancreatic pseudocysts are a common side effect of pancreatitis. They can complicate and extend your treatment, and even make you come back for more treatment just when you thought you were done. While this is dismaying, keep in mind that most pseudocysts won’t cause new problems or need interventions.
Healthcare providers take pseudocysts seriously, but they mostly watch them. They’ll also treat your symptoms, if you have any. When pseudocysts do need intervention, draining them usually does the trick. These procedures can almost always be accomplished by minimally invasive methods.
Last reviewed by a Cleveland Clinic medical professional on 10/11/2023.
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