Pancreatic pseudocysts in the 21st century. Part I: classification, pathophysiology, anatomic considerations and treatment.

A pseudocyst is present as a cystic cavity bound to the pancreas by inflammatory tissue [1]. Typically, the wall of a pancreatic pseudocyst lacks an epithelial lining, and the cyst contains pancreatic juice or amylase-rich fluid [2, 3]. This is the histopathological definition of a pancreatic pseudocyst. In the past, there have been several different clinical definitions of pancreatic pseudocysts and there are probably more to come in the future. Today, the most used definitions differentiate between peripancreatic fluid collections, pseudocysts and pancreatic abscesses as in the Atlanta classification system for acute pancreatitis [4]: