title: Difficult Diagnostic Problems in Pancreatobiliary Neoplasia.
abstract: BACKGROUND
  Many common diagnostic dilemmas are encountered in pancreatobiliary pathology, frequently resulting in uncertainty on behalf of the pathologist and referral for a second opinion.
  
  
  OBJECTIVE
  To review 4 common diagnostic dilemmas encountered in the practice of pancreatobiliary pathology: (1) pancreatic ductal adenocarcinoma versus chronic pancreatitis; (2) pancreatic ductal carcinoma versus adenocarcinomas arising in the ampulla and intrapancreatic common bile duct; (3) the distinction of uncommon intraductal neoplasms--intraductal oncocytic papillary neoplasm, intraductal tubulopapillary neoplasm, and intraductal acinar cell carcinoma; and (4) intrahepatic cholangiocarcinoma versus metastatic carcinoma.
  
  
  METHODS
  A review of pertinent literature, along with the authors' personal experience, based on institutional and consultation materials.
  
  
  CONCLUSIONS
  Important diagnostic features for a few challenging problems in pancreatobiliary pathology are reviewed. Careful study of the microscopic features along with awareness of differential diagnoses and diagnostic pitfalls generally allows distinction of these entities. We also highlight established and novel ancillary studies that help to arrive at an accurate diagnosis.
authors.forename: Jacob R
authors.initials: JR
authors.lastname: Bledsoe
authors.forename: Shweta A
authors.initials: SA
authors.lastname: Shinagare
authors.affiliation: From the Department of Pathology, Massachusetts General Hospital, Boston (Drs Bledsoe and Deshpande); and the Department of Pathology and Laboratory Medicine, Tufts Medical Center, Boston (Dr Shinagare).
authors.forename: Vikram
authors.initials: V
authors.lastname: Deshpande
mesh_terms: D001650:Bile Duct Neoplasms / Q000473:pathology*; D001653:Bile Ducts, Intrahepatic / Q000473:pathology*; D021441:Carcinoma, Pancreatic Ductal / Q000473:pathology*; D018281:Cholangiocarcinoma / Q000473:pathology*; D003937:Diagnosis, Differential; D006801:Humans; D010190:Pancreatic Neoplasms / Q000473:pathology*; D050500:Pancreatitis, Chronic / Q000473:pathology*