RADIOLOGY: PANCREAS: Case# 32880: PANCREATITIS, PSEUDOCYSTS DISSECTING INTO DIPHRAGMATIC HIATUS & INTO PLEURA. 66 year old male with hypertension and weight loss had bloody pleural effusion with elevated amylaise on thoracentesis. There is a large right pleural effusion with associated pleural thickening and slight enhancement. There are multiple, focal punctate calcifications throughout the pancreas, most noted in the pancreatic head and uncinate process regions. An associated 2.0 x 1.8cm pseudocyst is present in the pancreatic head. This pseudocyst extends superiorly through the diaphragmatic hiatus. There is also associated mild rugal thickening at the posterior aspect of the grastic wall which may represent inflammatory change. Pancreatic pseudocysts are usually the sequelae of pancreatitis, most often associated with the subacute or chronic varieties. Peripancreatic fluid collections in the setting of acute pancreatitis are not pseduocysts. A pseudocyst is a cystic structure with a thick, fibrous wall and is not lined with epithelium (hence, it is not a true cyst). A pseudocyst may have a persistent connection to the pancreatic duct which may be demonstrated by ERCP. Typically, an uncomplicated pseudocyst will have a homogeneous water density. Increased density or inhomogeneity indicate some complicating factor such as hemorrhage or infection. Psuedocysts may also form in the walls of bowel (stomach, duodenum, colon) due to extension of pancreatic enzymes into the surrounding tissues.