title: Pancreatic ductal adenocarcinomas with cystic features: neither rare nor uniform.
abstract: Cystic tumors of the pancreas are uncommon but important because of their diverse pathology and biology. Their wide spectrum also includes cystic variants of otherwise solid tumors, such as cystic endocrine tumors, cystic acinar cell carcinomas and ductal adenocarcinomas with cystic changes. In this study, we screened pancreatic ductal adenocarcinomas and their variants for macrocystic changes and determined the nature of the cysts (neoplastic vs non-neoplastic). Of 483 tumors 38 (8%) had cystic features. The largest group consisted of 24 pancreatic ductal adenocarcinomas showing a large-gland pattern with small cysts whose diameter varied between 0.5 and 1.8 cm. The epithelial lining of these cysts was generally positive for CEA (83%) and/or MUC1 (71%) and MUC5AC (74%). p53 was positive in 57% of the cases. The second group of cystic tumors (8/483) showed degenerative cystic cavities with diameters ranging between 1 and 6 cm. This group consisted of poorly differentiated pancreatic ductal adenocarcinomas, undifferentiated carcinomas with or without osteoclast-like giant cells and one adenosquamous carcinoma. In the third group of cystic tumors there were four pancreatic ductal adenocarcinomas containing tumor-related retention cysts. Their epithelial cells were positive for MUC5AC, but negative for CEA, MUC1 and p53. The fourth group consisted of two pancreatic ductal adenocarcinomas showing closely attached pseudocysts caused by tumor-associated pancreatitis. The results indicate that a considerable number of pancreatic ductal adenocarcinomas and their variants display cystic features and must therefore be considered in the differential diagnosis of cystic neoplasms of the pancreas. Moreover, not all of the cystic structures we observed were neoplastic in nature. They may also represent non-neoplastic changes, such as retention cysts and inflammatory pseudocysts.
authors.affiliation: Department of Pathology, University of Kiel, Germany. mkosmahl@path.uni-kiel.de
authors.forename: Markus
authors.initials: M
authors.lastname: Kosmahl
authors.forename: Ursula
authors.initials: U
authors.lastname: Pauser
authors.forename: Martin
authors.initials: M
authors.lastname: Anlauf
authors.forename: Günter
authors.initials: G
authors.lastname: Klöppel
mesh_terms: D000328:Adult; D000368:Aged; D002272:Carcinoembryonic Antigen / Q000378:metabolism; D021441:Carcinoma, Pancreatic Ductal / Q000378:metabolism / Q000473:pathology*; D003560:Cysts / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D055271:Mucin 5AC; D009077:Mucins / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D002272:Carcinoembryonic Antigen; C524678:MUC5AC protein, human; D055271:Mucin 5AC; D009077:Mucins; D016159:Tumor Suppressor Protein p53