Acute necrotic collection
Acute necrotic collections (ANCs) are an early, local complication of necrotizing pancreatitis.
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Terminology
The following are the latest terms according to the updated Atlanta classification to describe fluid collections associated with acute pancreatitis 1,2:
- fluid collections in interstitial edematous pancreatitis
- acute peripancreatic fluid collections (APFC): in the first 4 weeks: non-encapsulated peripancreatic fluid collections
- pseudocysts: develop after 4 weeks; encapsulated peripancreatic or remote fluid collections
- fluid collections in necrotizing pancreatitis
- acute necrotic collections (ANCs): in the first 4 weeks; non-encapsulated heterogeneous non-liquefied material
- walled-off necrosis (WON or WOPN): develop after 4 weeks; encapsulated heterogeneous non-liquefied material
Pathology
Acute necrotic collections develop within the first four weeks and contain a variable amount of fluid/non-liquid necrotic material. They may be pancreatic or peripancreatic in location and can be sterile or infected.
Radiographic features
CT
On contrast-enhanced CT the following features are seen:
- heterogeneous, non-liquid density collection within the pancreas and/or peripancreatic tissues
- no defined capsule
- no peripheral enhancement
Differential diagnosis
- acute peripancreatic fluid collections (APFC): within the first week, differentiation between acute necrotic collections (ANC) and APFC may prove impossible
Related Radiopaedia articles
Pancreatic pathology
-
pancreatic neoplasms
- cystic neoplasm (cystic pancreatic mass differential diagnosis)
- solid neoplasm
- nonepithelial pancreatic neoplasms
- others
- simple pancreatic cyst
-
pancreatitis (mnemonic for the causes)
- acute pancreatitis
- chronic pancreatitis
- Ascaris-induced pancreatitis
- tropical pancreatitis
- autoimmune pancreatitis
- emphysematous pancreatitis
- hypertriglyceridemia-induced pancreatitis
- hereditary pancreatitis
- pancreatitis associated with cystic fibrosis
- pancreaticopleural fistula
- segmental pancreatitis
- pancreatic atrophy
- pancreatic lipomatosis
- pancreatic trauma