title: Intraductal oncocytic papillary neoplasms of the pancreas and bile ducts: a description of five new cases and review based on a systematic survey of the literature.
abstract: BACKGROUND
  Intraductal oncocytic papillary neoplasms (IOPN) are rare tumors of the pancreatic and biliary ductal system. It is not absolutely clear if the molecular and clinicopathologic characteristics of IOPN differ significantly from other related lesions, namely intraductal papillary mucinous neoplasms (IPMN). Therefore it is not clear if it is reasonable to consider IOPN as a separate diagnostic and clinical entity.
  
  
  METHODS
  In order to describe the clinicopathologic characteristics of IOPN and to compare them with the IPMN profile, we performed a systematic review of the literature and additionally studied five previously unreported IOPN cases.
  
  
  RESULTS
  IOPN differ from IPMN by lack of K-ras gene mutations in all studied cases. Several differences in the clinical and biological profile between IOPN and IPMN exist, but they are of quantitative rather than of qualitative nature. Additionally, pancreaticobiliary or gastric-foveolar IPMN components may coexist with IOPN component within a single lesion, which suggests at least a partial relation of the pathogenetic pathways of IPMN and IOPN. Importantly, the pathogenesis of accumulation of mitochondria and oxyphilic appearance of IOPN remains unknown.
  
  
  CONCLUSIONS
  At present, there are no reliable criteria other than histopathological picture and K-ras gene status to differentiate IOPN from IPMN. In particular, no clear differences in optimal treatment options and prognosis between these tumors are known. Further studies are needed to clarify the biology of IOPN and to establish their position in clinicopathologic classifications of pancreatic tumors.
authors.affiliation: Department of Histopathology, Medical University of Silesia, ul. Medyków 18, 40-754, Katowice, Poland. LLISZKA@MP.PL
authors.forename: Lukasz
authors.initials: L
authors.lastname: Liszka
authors.forename: Jacek
authors.initials: J
authors.lastname: Pajak
authors.forename: Ewa
authors.initials: E
authors.lastname: Zielińska-Pajak
authors.forename: Lukasz
authors.initials: L
authors.lastname: Krzych
authors.forename: Dariusz
authors.initials: D
authors.lastname: Gołka
authors.forename: Sławomir
authors.initials: S
authors.lastname: Mrowiec
authors.forename: Paweł
authors.initials: P
authors.lastname: Lampe
mesh_terms: D001650:Bile Duct Neoplasms / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*; D021441:Carcinoma, Pancreatic Ductal / Q000473:pathology*; D002291:Carcinoma, Papillary / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*; D003937:Diagnosis, Differential; D011905:Genes, ras / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D009077:Mucins / Q000378:metabolism; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*
chemical_list: D009077:Mucins