A pancreatic pseudocyst is an encapsulated collection of pancreatic fluid surrounded by a mature non-epithelialized wall, typically occurring after pancreatitis or pancreatic duct disruption. --- ### Essential Takeaway Pancreatic pseudocysts are delayed fluid collections that usually arise following acute or chronic pancreatitis. Most resolve without intervention. Management depends on symptoms, infection, obstruction, interval progression, and ductal anatomy rather than size alone. --- ### Definition Under the Revised Atlanta Classification, a pancreatic pseudocyst is: - a mature encapsulated peripancreatic fluid collection - with minimal or no solid necrotic material - typically developing >4 weeks after interstitial edematous pancreatitis Pseudocysts lack a true epithelial lining, distinguishing them from cystic neoplasms. --- ### Pathogenesis Pseudocysts result from: - pancreatic duct disruption - leakage of pancreatic secretions - inflammatory fluid organization over time Common settings: - acute pancreatitis - chronic pancreatitis - pancreatic trauma - postoperative pancreatic leak --- ### Clinical Presentation - Often asymptomatic - Abdominal pain/fullness - Early satiety - Nausea/vomiting - Gastric outlet obstruction - Biliary obstruction - Infection or hemorrhage (less common) --- ### Imaging Features #### CT / MRI Typical findings: - well-circumscribed fluid collection - mature enhancing wall - minimal internal debris - adjacent pancreatitis changes - ductal communication may be present > [!info] Note > Internal necrotic debris suggests **walled-off necrosis (WON)** rather than pseudocyst. --- ### Differential Diagnosis | Lesion | Distinguishing Feature | | --------------- | -------------------------------------- | | IPMN | Ductal neoplasm with mucinous biology | | MCN | Ovarian-type stroma; usually body/tail | | SCN | Microcystic/honeycomb appearance | | WOPN | Significant necrotic debris | | Cystic PNET/SPN | Solid enhancing components | Clinical history is critical. A “pseudocyst” without antecedent pancreatitis should raise concern for cystic neoplasm. --- ### Management Principles #### Observation Most asymptomatic pseudocysts can be observed. Intervention is generally reserved for: - symptoms - infection - obstruction - enlarging collections - bleeding - persistent duct leak/disruption --- ### Drainage Approaches | Approach | Typical Use | |---|---| | Endoscopic cystgastrostomy | Preferred for many mature symptomatic collections | | Percutaneous drainage | Selected patients or infected collections | | Surgical drainage | Complex anatomy, failed endoscopic management, associated operative indication | --- ### Ductal Anatomy Matters Disconnected duct syndrome and persistent duct disruption significantly affect recurrence risk and long-term management. ERCP may help: - define duct anatomy - identify leaks - guide transpapillary stenting in selected cases --- ### Practical Nuance Historically, pseudocysts >6 cm or present >6 weeks were often drained routinely. Modern management is more symptom- and biology-driven. Size alone is not an indication for intervention.