A pancreatic pseudocyst is a localised collection of pancreatic juice. It may be within, adjacent to, or remote from the pancreas - ie intrasplenic or mediastinal.
Pancreatic pseudocysts are formed by pancreatic secretions escaping from a ruptured duct, and do not have an epithelial lining. Occasionally they contain small amounts of necrotic debris. Persistence of the pseudocyst indicates continuing communication with the duct.
Typically, acute pancreatitis causes pseudocyst formation in 50% of cases with first symptoms evolving four weeks after the episode.
The pseudocyst may:
- enlarge, causing pain and biliary or pyloric obstruction
- become infected, forming an abscess
- rupture into the peritoneum, leading to ascites
- erode a vessel, causing severe haemorrhage