Abstract
A better understanding of the pathophysiology of necrotising pancreatitis and its outcomes as well as improved diagnostic imaging has made it necessary to revise the Atlanta Classification 1992. In the revised classification 2012, the term 'pancreatic abscess' is not used and instead a new concept of walled-off necrosis (WON) has been adopted. WON is a mature, encapsulated collection of pancreatic and/or peripancreatic necrosis (variable amounts of both fluid and necrosis associated with necrotising pancreatitis) and has a well defined inflammatory wall; usually this maturation occurs ≥4 weeks after onset of necrotising pancreatitis. In the revised classification, an important distinction is made between collections that are composed of fluid alone (fluid collections) versus those that arise from necrosis and contain a solid component (necrotic collections): the latter is subdivided into acute necrotic collection (ANC) and WON. Infection of ACN or WON is defined as infected necrosis.
