A pseudocyst is a medical condition characterized by a collection of fluid and debris that forms in or around organs, most commonly the pancreas. These fluid-filled sacs are a consequence of inflammation or injury to the affected organ. Understanding pseudocysts involves recognizing their unique characteristics and how they differ from other types of fluid collections in the body.
What Exactly Is a Pseudocyst?
A pseudocyst refers to a fluid-filled sac that develops in the abdomen, frequently near the pancreas. It contains pancreatic enzymes, fluid, and dead tissue. The term “pseudo” means false, indicating it lacks a true epithelial lining, distinguishing it from a true cyst. Instead, a pseudocyst is surrounded by a fibrous, scar-like tissue wall, formed by the body’s response to inflammation or injury. This capsule encapsulates leaked pancreatic fluids, preventing further spread into the abdominal cavity.
Pseudocyst formation begins when the pancreas is inflamed or injured, causing digestive enzymes to leak. These enzymes can irritate and damage surrounding tissues. The body then attempts to contain this leakage by forming a fibrous wall around the fluid collection. Unlike true cysts, which can be cancerous, pseudocysts are almost always benign and develop as a complication of an underlying condition.
Why Do They Form and What Are the Signs?
Pseudocysts primarily form as a complication of pancreatitis, an inflammation of the pancreas. Both acute (sudden) and chronic (long-lasting) pancreatitis can lead to their development. Common causes include gallstones and excessive alcohol consumption. Less common causes involve abdominal trauma, certain medications, high triglycerides or calcium, and some autoimmune diseases.
Symptoms vary; smaller pseudocysts sometimes cause no noticeable signs. Larger ones often present with symptoms similar to pancreatitis, appearing weeks after an acute episode. Common signs include persistent upper abdominal pain, which may radiate to the back, nausea, and vomiting. A person might also experience a swollen abdomen, loss of appetite, or difficulty digesting food. A physical examination may reveal a palpable mass in the upper abdomen.
How Are They Discovered and Treated?
Pseudocysts are often discovered using medical imaging. Healthcare providers commonly use computed tomography (CT) scans, magnetic resonance imaging (MRI), and ultrasound to visualize the fluid collection and determine its characteristics. A CT scan provides detailed information about the pseudocyst’s size and structure, while an MRI offers sharper images and helps differentiate it from other cysts. Endoscopic ultrasound (EUS) may also be used for a more detailed view or to collect a fluid sample if the diagnosis remains unclear.
Treatment depends on pseudocyst size, symptoms, and complications. Many small, asymptomatic pseudocysts, especially after acute pancreatitis, resolve with watchful waiting. If intervention is necessary, endoscopic drainage is often preferred. This procedure uses an endoscope to connect the pseudocyst to the digestive tract, allowing internal fluid drainage. Surgical drainage may be considered for complex or persistent cases, or when endoscopic methods are not feasible.
What to Expect: Outlook and Complications
The outlook for individuals with pseudocysts is generally favorable, as many, particularly smaller ones, resolve spontaneously without intervention. Spontaneous resolution is more likely for pseudocysts under 4 cm and those causing mild or no symptoms. Close medical follow-up is important to monitor progression and identify potential complications.
Complications, though not always common, can include infection, rupture, bleeding, or obstruction of nearby organs. An infected pseudocyst can lead to sepsis, while rupture into the abdominal cavity can cause severe pain and peritonitis, a life-threatening condition. Large pseudocysts might also compress the bile duct, leading to jaundice, or obstruct the stomach or small intestine, causing digestive problems. Immediate medical attention is necessary if symptoms such as severe abdominal pain, fever, vomiting blood, dizziness, or yellowing of the skin develop.