"The term pancreatic pseudocyst has historically been used broadly, and older literature often applied it to mature pancreatic fluid collections of different aetiologies. Since publication of the 2012 Revised Atlanta Classification, terminology for collections related to acute pancreatitis has become more specific10,11:"
"Pseudocysts are surrounded by fibrous and granulation tissuerather than epithelium, with wall maturation usually requiring about 4–6 weeks8,9.The pathophysiology depends on the clinical context:"
"Communication with the pancreatic duct may occur2, particularly in chronic pancreatitis and in collections related to ductal disruption, and is clinically relevant because it increases the chance of persistence or recurrence after drainage."
"Pseudocysts are surrounded by fibrous and granulation tissuerather than epithelium, with wall maturation usually requiring about 4–6 weeks8,9.The pathophysiology depends on the clinical context:"
"In acute pancreatitis, a pseudocyst represents the mature stage of an APFC following interstitial oedematous pancreatitis."
"In chronic pancreatitis, pseudocysts usually result from pancreatic duct obstruction or disruption related to stones, strictures, or protein plugs, with persistent leakage of pancreatic juice."
"useful for demonstrating communication with the pancreatic duct."
"may show duct disruption and duct leak."
"intramural pseudocysts 19-20"
"walled-off necrosis (WON/WOPN): develop after 4 weeks; encapsulated heterogeneous non-liquefied material"
"walled-off necrosis (WON/WOPN): develop after 4 weeks; encapsulated heterogeneous non-liquefied material"
"Accordingly, in the setting of acute pancreatitis, collections containing true necrotic debris should be classified as WON rather than pseudocyst."
"According to the revised Atlanta classification, pseudocysts contain no non-liquefied components within the fluid collection, as even minimal amounts of fat or soft-tissue attenuation would make it a WON 10,21."
"Layering or dependent internal material has been described in older MR literature as a feature of pseudocyst; however, in contemporary practice this should be interpreted in light of aetiology. In acute pancreatitis, true necrotic debris favours WON; in chronic pancreatitis or trauma, internal material may instead reflect haemorrhagic or proteinaceous contents."
"often requires endoscopic FNA for definitive diagnosis 6"
"In chronic pancreatitis and pancreatic trauma, the term pseudocyst remains appropriate for mature encapsulated collections that arise primarily from duct disruption or persistent duct leakage. In these settings, the contents may occasionally be haemorrhagic, fibrinous, or proteinaceous, resulting in internal echoes or debris-like material on imaging without necessarily implying pancreatic necrosis. This distinction explains part of the inconsistency in older literature."
"Pseudocysts appear as well-circumscribed, usually round or oval peripancreatic fluid collections of homogeneously low attenuation, that are usually surrounded by a well-defined enhancing wall 10. Calcification of the wall of a pseudocyst is rare and an alternative diagnosis should always be considered 22,23."
"MRCP"
Expected headings
"Subtypes"
"MRCP"
"pseudocysts: develop after 4 weeks; encapsulated peripancreatic or remote fluid collections"
"acute necrotic collection (ANC): in the first 4 weeks; non-encapsulated heterogeneous non-liquefied material"
"walled-off necrosis (WON/WOPN): develop after 4 weeks; encapsulated heterogeneous non-liquefied material"
"Layering or dependent internal material has been described in older MR literature as a feature of pseudocyst; however, in contemporary practice this should be interpreted in light of aetiology. In acute pancreatitis, true necrotic debris favours WON; in chronic pancreatitis or trauma, internal material may instead reflect haemorrhagic or proteinaceous contents."
"Layering or dependent internal material has been described in older MR literature as a feature of pseudocyst; however, in contemporary practice this should be interpreted in light of aetiology. In acute pancreatitis, true necrotic debris favours WON; in chronic pancreatitis or trauma, internal material may instead reflect haemorrhagic or proteinaceous contents."
"Although pancreatic pseudocyst may regress on its own and requires no further treatment, interventions are required in selected cases, particularly those complicated with infections, large size causing mass effect symptoms such as gastric outlet obstruction, bowel obstruction, hydronephrosis and biliary obstruction, diameter increasing in size or greater than 5 cm, recurrence following previous resection or aspiration, and persistent symptoms 14,16,17."
"Although pancreatic pseudocyst may regress on its own and requires no further treatment, interventions are required in selected cases, particularly those complicated with infections, large size causing mass effect symptoms such as gastric outlet obstruction, bowel obstruction, hydronephrosis and biliary obstruction, diameter increasing in size or greater than 5 cm, recurrence following previous resection or aspiration, and persistent symptoms 14,16,17."