Pseudocyst Drainage (Cystogastrostomy)
What the Examiner Expects
Internal drainage of a pancreatic pseudocyst into an adjacent hollow viscus, most commonly the stomach (cystogastrostomy) or a Roux-en-Y jejunal limb (cystojejunostomy). The examiner expects you to distinguish a true pseudocyst (encapsulated collection of pancreatic fluid without an epithelial lining, arising after acute pancreatitis) from a cystic neoplasm (MCN, IPMN — these must NOT be drained internally). Pseudocyst fluid has high amylase and low CEA; cystic neoplasms have elevated CEA. Intervention is indicated for symptomatic pseudocysts (pain, gastric outlet obstruction, biliary obstruction) that have persisted > 6 weeks with a mature wall. EUS-guided endoscopic cystogastrostomy has become the preferred first-line approach.
Key Examiner Focus Points
- Internal drainage indicated for symptomatic pseudocysts > 6 cm persisting > 6 weeks
- Cystogastrostomy: drainage into posterior stomach wall (most common)
- Cystojejunostomy (Roux-en-Y): for pseudocysts not adherent to the stomach
- Must distinguish pseudocyst from cystic neoplasm (MCN, IPMN) — send fluid for CEA and amylase
- Endoscopic (EUS-guided) cystogastrostomy is now first-line approach
Common Curveballs
Cyst fluid analysis shows elevated CEA and low amylase
This is NOT a pseudocyst — this is a cystic neoplasm (likely mucinous cystadenoma/MCN). Internal drainage is contraindicated because it would incompletely treat a potentially malignant lesion. The patient needs surgical resection (distal pancreatectomy for body/tail lesions).
After cystogastrostomy, the pseudocyst recurs
Evaluate for a disconnected pancreatic duct syndrome (DPDS) — disruption of the main pancreatic duct at the site of necrosis, isolating the upstream pancreas. MRCP or ERCP can confirm. DPDS requires either long-term transmural stent drainage or distal pancreatectomy of the disconnected segment.
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