Complex sentence: Late complications include recurrent pancreatitis and the development of pancreatic pseudocysts--collections of pancreatic secretions which have been walled off by scar and inflammatory tissue.
Split into simpler sentences: Late complications include recurrent pancreatitis and the development of pancreatic pseudocysts. A pancreatic pseudocyst is essentially a collection of pancreatic secretions which has been walled off by scar and inflammatory tissue.