title: Invasive ductal adenocarcinoma of the pancreas may originate from the larger pancreatic duct: a study of 13 tumors less than 2 cm in diameter.
abstract: OBJECTIVE
  We aimed to elucidate the origin/primary site of invasive ductal adenocarcinoma of the pancreas, based on the distribution of intraductal carcinoma components. These components were identified by a mural elastic fiber cuff.
  
  
  METHODS
  Thirteen specimens from patients with invasive ductal adenocarcinoma (microscopically, less than 2 cm in diameter) of the pancreas were studied histopathologically. Variants of invasive ductal adenocarcinoma and intraductal papillary-mucinous carcinoma were excluded.
  
  
  RESULTS
  Intraductal carcinoma components of invasive ductal adenocarcinoma were found in 12 of the specimens 13 (92%), and were observed within the tumor mass and/or on its boundary, or outside the tumor mass. Intraductal components were characterized by low papillary projections lacking a fibrovascular core, with/without surrounding tubular structures, or by irregular stratification and pleomorphism of the epithelial cells. Invasive components mostly showed a tubular pattern with desmoplasia. The distribution of the intraductal components in the 12 specimens was as follows: in 9 (75%), they were in both the main pancreatic duct and large branch ducts; and in 3, they were in the smaller branch ducts only.
  
  
  CONCLUSIONS
  Invasive ductal adenocarcinomas of the pancreas may originate most frequently from the main pancreatic duct or larger branch ducts, while the smaller ducts are less often the site of cancer origin.
authors.affiliation: Department of Pathology, Juntendo University School of Medicine, 2-1-1 Hongo, Tokyo 113-8421, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Suda
authors.forename: Bunsei
authors.initials: B
authors.lastname: Nobukawa
authors.forename: Shigetaka
authors.initials: S
authors.lastname: Yamasaki
authors.forename: Keiko
authors.initials: K
authors.lastname: Abe
authors.forename: Susumu
authors.initials: S
authors.lastname: Matsukuma
authors.forename: Fujihiko
authors.initials: F
authors.lastname: Suzuki
mesh_terms: D000328:Adult; D000368:Aged; D002278:Carcinoma in Situ / Q000473:pathology / Q000601:surgery; D021441:Carcinoma, Pancreatic Ductal / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D010183:Pancreatic Ducts / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000473:pathology* / Q000601:surgery; D016577:Pancreaticoduodenectomy; D012189:Retrospective Studies; D012720:Severity of Illness Index