Pancreatic pseudocyst is a nonepithelial lined, fibrous walled, cystic fluid collection that arises from pancreatic duct disruption and leakage of amylase rich fluid into the peripancreatic tissue.
Early in the pathogenesis of a pseudocyst (before fibrous wall formation), the fluid collection is better called "acute fluid collection". The majority of these fluid collections resolve spontaneously. Those that persist become walled off to form pseudocysts.
Pseudocysts occur in 5-15% of acute pancreatitis cases and 30% of chronic pancreatitis cases.
Pseudocysts that follow acute pancreatitis can resolve spontaneously. Those that are associated with chronic pancreatitis (duct stricture or pancreatic calcifications) rarely do so.
Indications for Treatment
Current evidence support non operative treatment for all asymptomatic pseudocysts regardless of the duration or size. Treatment is reserved for:
- Symptomatic pseudocysts
- Complicated pseudocysts
- Endoscopic drainage by transgastric approach
- Surgical drainage: for those not suitable for endoscopic drainage and fit for surgery
- Percutaneous drainage: for high risk patients not suitable for endoscopic drainage
Cysts that are suspicious of being cystic neoplasms should be treated with surgical resection rather than drainage.
Pseudocysts that abut the posterior wall of the stomach or the duodenum are drained internally by transmural drainage into the stomach or duodenum. The requirements are:
- Distance less that 1 cm
- No extensive collateral blood vessels from splenic vein thrombosis
- No thick debris
Double-pigtail catheters are inserted to keep the tract open.
The success rate is 80-90% with 75% incidence of pseudocyst resolution.
Complications occur in around 20% : bleeding perforation and infection.
1. Failed or not candidates for endoscopic therapy
2. Complicated pseudocysts: infection, rupture or pseudoaneurysm
Depend on location:
- Roux-en-Y cystjejunosotmy
- Distal pancreatectomy
Success rate: 90-100%
Patients with pseudocysts and dilated pancreatic duct >7 mm should be considered for lateral pancreaticojejunosotomy as sole procedure.