OVERVIEW

What is pancreatic pseudocyst?

Pancreatic pseudocyst is a special type of pancreatic cyst, classified under inflammatory effusion. It is a local complication of pancreatitis, appearing as a cystic lesion around the pancreas on imaging, with a thin or thick cyst wall that may contain septations. A characteristic feature is the absence of epithelial lining on pathological examination of the cyst wall, distinguishing it from true cysts.

According to the revised 2013 Atlanta classification of acute pancreatitis, inflammatory effusions can be divided into four types: acute peripancreatic fluid collection, pseudocyst, acute necrotic collection, and walled-off pancreatic necrosis. However, in the Chinese medical community, the concept of pancreatic pseudocyst often overlaps with acute necrotic collection and walled-off pancreatic necrosis, and the three are sometimes not strictly distinguished.

Who is prone to pancreatic pseudocyst?

Pancreatic pseudocyst mainly occurs in patients with pancreatitis, including both acute and chronic pancreatitis. It can also develop in some cases of pancreatic trauma or pancreatic duct rupture.

As a local complication of pancreatitis, pancreatic pseudocyst forms when peripancreatic inflammatory fluid accumulates and fails to resolve over time, becoming encapsulated by surrounding tissues to form a cyst-like structure.

SYMPTOMS

What are the common manifestations of pancreatic pseudocysts?

• Symptoms of pancreatitis: Patients with pancreatic pseudocysts often exhibit clinical manifestations of pancreatitis, including abdominal distension and pain, nausea and vomiting, loss of appetite, and indigestion.

• Mass compression symptoms: Pancreatic pseudocysts may also cause mass effects, leading to corresponding clinical symptoms. The specific manifestations vary depending on the location and size of the cyst.

• Smaller cysts may cause no discomfort and are only detected during imaging follow-ups.

• Larger pseudocysts may present as a palpable mass in the upper abdomen. If located in the pancreatic head, they may compress the bile duct and/or duodenum, leading to jaundice or gastrointestinal obstruction. Compression of the portal vein or splenic vein may result in pancreatic portal hypertension, splenomegaly, hypersplenism, or gastric varices.

What are the potential consequences of pancreatic pseudocysts?

• Most pseudocysts are self-limiting. As inflammation subsides, the cystic fluid may gradually be absorbed, and follow-up examinations may reveal complete resolution of the cyst.

• A small proportion of cysts fail to resolve after a certain period and may require intervention. Patients may need endoscopic or surgical drainage of the cystic fluid.

• A few patients with pseudocysts may develop secondary infections, leading to pancreatic abscesses and systemic sepsis.

• Pancreatic pseudocysts typically do not become malignant. However, they can sometimes be difficult to distinguish from pancreatic cystic tumors, necessitating biopsy or surgery with pathological examination for definitive diagnosis.

CAUSES

What are the common causes of pancreatic pseudocysts?

• The cause of pancreatic pseudocysts is pancreatitis. Various types of pancreatitis can lead to secondary pancreatic pseudocysts, with acute pancreatitis and chronic pancreatitis being the most common. Patients are often first diagnosed with pancreatitis, and pseudocysts are later confirmed during follow-up treatment or examinations.

• A very small number of patients are found to have pancreatic pseudocysts without a clear history of pancreatitis. It is speculated that this may be related to asymptomatic or mild pancreatitis episodes that resolved on their own, or cases where medical attention was not sought promptly, leading to undetected inflammation.

• Pancreatic pseudocysts may also develop after pancreatic trauma.

DIAGNOSIS

How is pancreatic pseudocyst diagnosed? What tests are needed?

• For patients with a history of pancreatitis, imaging tests such as ultrasound, CT, or MRI should be performed. The discovery of a cystic lesion around the pancreas suggests a diagnosis of pseudocyst. Patients may exhibit a series of clinical symptoms caused by the cystic mass. Imaging tests are the primary basis for diagnosing pancreatic pseudocysts. CT and/or MRI, MRCP are the most commonly used methods for evaluating cysts.

• Pathological diagnosis is the gold standard for definitive diagnosis of pancreatic pseudocysts, with the absence of epithelial lining being its typical feature. For cases where differentiation from pancreatic cystic tumors is difficult, cyst fluid aspiration biopsy or core needle biopsy may be required.

TREATMENT

Which department should I visit for pancreatic pseudocysts?

Gastroenterology or hepatobiliary and pancreatic surgery.

What are the treatment options for pancreatic pseudocysts?

After clinical diagnosis of pancreatic pseudocysts, one approach is close follow-up observation while actively treating the underlying pancreatitis. The other option is surgical or endoscopic intervention.

• Pseudocysts are a type of inflammatory fluid collection. Most patients can absorb them spontaneously without special treatment, requiring only regular follow-up. However, for cysts persisting beyond 6 weeks and exceeding 6 cm in size—where spontaneous absorption is unlikely—intervention is needed. Interventions typically include surgical drainage or endoscopic therapy.

• Surgical options include internal and external drainage.

• Internal drainage involves cystogastrostomy or cystojejunostomy, allowing cyst fluid to drain into the digestive tract.

• External drainage directs cyst fluid outside the body. Since cyst fluid is essentially pancreatic juice with digestive functions, internal drainage is more physiologically appropriate and thus more commonly used.

• Surgery can be performed via traditional open surgery or laparoscopy. The principle is to achieve low-positioned, adequate drainage. For cases with necrotic tissue, percutaneous drainage with repeated debridement via sinus tract formation has recently been employed, often assisted by percutaneous nephroscopy, choledochoscopy, laparoscopy, or even gastroscopy.

• Endoscopic treatment mainly involves transgastric or transintestinal wall puncture with stent placement for drainage. Another approach is pancreatic duct stenting to reduce main pancreatic duct pressure, promoting pancreatic juice drainage and pseudocyst resolution.

Can pancreatic pseudocysts be cured? Will they recur?

• Small pseudocysts without surgical or endoscopic intervention often resolve after acute inflammation subsides. However, recurrence is possible if pancreatitis flares up again.

• For pseudocysts treated surgically or endoscopically, recurrence at the original site is unlikely due to the new drainage pathway, but recurrence elsewhere remains possible. In patients with recurrent pancreatitis, pseudocysts may enlarge or shrink with inflammation. They may be undetectable during non-acute phases but rapidly enlarge during acute episodes.

DIET & LIFESTYLE

What should patients with pancreatic pseudocysts pay attention to in daily life?

• Eat regular and measured meals daily, choosing easily digestible foods, and strictly avoid greasy foods and overeating. When pancreatic disease occurs, it indicates that the pancreas's secretory function has been impaired to varying degrees, especially its ability to digest fats and proteins, which may lead to loss of appetite or characteristic fatty stools. Therefore, if fat droplets are found in the stool, seek medical follow-up promptly.

• Strictly abstain from alcohol: Alcohol stimulates excessive pancreatic secretion, obstructs pancreatic fluid drainage, disrupts pancreatic blood flow, and reduces trypsin inhibitors. Patients with chronic pancreatitis must avoid alcohol to prevent acute attacks.

• Maintain adequate rest, avoid fatigue, emotional agitation, and stress, as these can weaken the body's resistance and trigger disease recurrence. Engage in moderate activity while balancing work and rest.

• Patients with undiagnosed pseudocysts or those recovering from pancreatitis require follow-up imaging to assess potential pseudocyst formation.

• For suspected or confirmed pseudocysts, evaluate whether surgical or endoscopic treatment is needed while scheduling regular follow-ups to differentiate from pancreatic cystic tumors or cystic pancreatic cancer. Patients with recurrent pancreatitis should particularly avoid factors that may trigger flare-ups to prevent repeated episodes.

PREVENTION

Can pancreatic pseudocysts be prevented? How to prevent them?

Preventing pancreatic pseudocysts essentially involves preventing acute pancreatitis and acute exacerbations of chronic pancreatitis.

• For patients with biliary diseases or hypertriglyceridemia, active treatment of the underlying condition is necessary.

• For high-risk groups of acute pancreatitis, education, dietary improvements, smoking and alcohol cessation, and correcting unhealthy habits can aid in prevention.

• At-risk or high-risk individuals should enhance disease awareness, remain vigilant, and undergo regular check-ups to detect and diagnose pancreatic cysts early. Accurate evaluation to determine the nature of the lesion and appropriate treatment can lead to better outcomes.