A pancreatic pseudocyst is a benign, fluid-filled sac that develops outside the pancreas, typically in the surrounding area. The term “pseudo” means it lacks the specialized epithelial cell lining found in true cysts. Instead, the pseudocyst is enclosed by a wall of fibrous tissue that forms in response to inflammation. This fluid collection is rich in pancreatic enzymes, blood, and debris, and is a common complication following injury to the pancreas.
How Pseudocysts Form and Who is at Risk
Pancreatic pseudocysts arise almost exclusively as a consequence of pancreatitis (inflammation of the pancreas), whether acute or chronic. The primary mechanism involves damage to the pancreatic duct system, causing digestive enzymes and fluid to leak into the surrounding tissues. These enzymes trigger an intense inflammatory response.
Over several weeks, the body attempts to contain this leaked fluid by forming a protective layer of fibrous tissue around the collection. This encapsulation prevents the digestive fluids from spreading, creating the pseudocyst structure. The fluid inside is initially sterile, though it may become infected later.
The conditions that lead to pancreatitis are the main risk factors. Heavy, long-term alcohol consumption is a leading cause, often resulting in chronic pancreatitis. Gallstones, which can block the pancreatic duct, represent the second most common cause. Other risk factors include direct abdominal trauma, certain medications, and high levels of triglycerides in the blood.
Recognizing the Signs and Diagnostic Methods
Smaller pseudocysts often do not produce symptoms and may be discovered incidentally during imaging for an unrelated condition. As the pseudocyst grows, it can press on surrounding organs, leading to various signs. The most frequent symptom is persistent abdominal pain, which may radiate to the back and is often distinct from the initial pain of pancreatitis.
Patients may also experience nausea, vomiting, and a feeling of fullness after eating small amounts due to pressure on the stomach. A doctor may sometimes feel a tender, palpable mass in the upper abdomen during a physical examination. If the pseudocyst compresses the bile duct, the patient may develop jaundice.
Diagnosis relies heavily on cross-sectional imaging. A contrast-enhanced Computed Tomography (CT) scan is typically the initial diagnostic tool, showing the size, location, and wall thickness of the pseudocyst. Magnetic Resonance Imaging (MRI) and Magnetic Resonance Cholangiopancreatography (MRCP) are used for a more detailed picture, particularly to determine if the cyst connects to the main pancreatic duct. Blood tests, such as those measuring amylase and lipase, may be elevated but are not definitive for diagnosis.
Management and Treatment Approaches
Management begins with watchful observation, as many small, asymptomatic collections resolve on their own. Cysts less than six centimeters in diameter that do not cause symptoms are monitored with follow-up imaging to ensure they are not growing. This approach allows the body’s natural healing process to take place.
Intervention is necessary if the cyst is large, causes persistent symptoms, or fails to decrease in size after several weeks. The preferred modern treatment is minimally invasive drainage, most commonly performed endoscopically.
Endoscopic Drainage
Endoscopic Ultrasound (EUS)-guided drainage involves passing an endoscope to the stomach or duodenum, where the pseudocyst bulge is identified. A small opening is created, and a stent is placed to connect the pseudocyst cavity directly to the digestive tract, allowing internal drainage.
Another method is percutaneous drainage, where a catheter is inserted through the skin and abdominal wall directly into the pseudocyst under imaging guidance. This is often reserved for infected pseudocysts that require immediate relief and continuous external drainage. Open surgery, involving creating a permanent connection between the cyst and the digestive tract (cystogastrostomy), is now reserved for complex cases or when minimally invasive methods have failed.
When Things Go Wrong: Potential Complications
While many pseudocysts resolve without issue, they carry the potential for complications requiring medical attention. The most common issue is infection within the fluid collection, which transforms the pseudocyst into a pancreatic abscess. This condition can lead to sepsis and be life-threatening if not drained immediately.
Rupture is a concern, though rare. If the pseudocyst bursts into the abdominal cavity, it can cause peritonitis (inflammation of the abdominal lining). Rupture into the gastrointestinal tract can also occur and may be associated with bleeding.
Hemorrhage, or significant internal bleeding, can happen if the pseudocyst erodes into a nearby blood vessel, such as the splenic artery. This severe complication, known as intracystic hemorrhage, can lead to massive blood loss and shock. Any sudden worsening of abdominal pain or signs of internal bleeding should prompt immediate emergency care.