title: Natural history of branch duct intraductal papillary mucinous neoplasms of the pancreas: a multicenter study in Japan.
abstract: OBJECTIVE
  The aim of this study was to evaluate the long-term follow-up results of patients with branch duct intraductal papillary mucinous neoplasms (BD-IPMNs) without mural nodules (MNs) at 10 representative institutions in Japan.
  
  
  METHODS
  We analyzed 349 follow-up BD-IPMN patients who had no MNs on endoscopic ultrasonography at initial diagnosis.
  
  
  RESULTS
  Observation periods ranged from 1 to 16.3 years (median, 3.7 years). Sixty-two (17.8%) patients exhibited disease progression during follow-up. Twenty-two underwent surgery, leading to a pathological diagnosis of carcinoma in 9 and adenoma in 13. Although the remaining 287 (82.2%) showed no changes, 7 underwent surgery because of symptoms (n = 2), choice (n = 2), or development of pancreatic ductal adenocarcinoma (n = 3); all of them were diagnosed pathologically as adenomas. Of the 29 patients undergoing surgery, all 9 with carcinoma exhibited signs of progression, such as increased main pancreatic duct diameter and/or appearance of MNs. Pancreatic ductal adenocarcinomas and additional BD-IPMNs developed in 7 (2.0%) and 13 (3.7%), respectively. Overall, 320 (91.7%) patients were followed without surgery.
  
  
  CONCLUSIONS
  Most BD-IPMN patients who had no MNs on endoscopic ultrasonography could be managed without surgery. However, careful attention should be paid to disease progression and the development of pancreatic ductal adenocarcinomas during follow-up.
authors.affiliation: Working Group of the Japan Pancreas Society, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Maguchi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tanno
authors.forename: Nobumasa
authors.initials: N
authors.lastname: Mizuno
authors.forename: Keiji
authors.initials: K
authors.lastname: Hanada
authors.forename: Go
authors.initials: G
authors.lastname: Kobayashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Hatori
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Sadakari
authors.forename: Taketo
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Kosuke
authors.initials: K
authors.lastname: Tobita
authors.forename: Ryuichiro
authors.initials: R
authors.lastname: Doi
authors.forename: Akio
authors.initials: A
authors.lastname: Yanagisawa
authors.forename: Masao
authors.initials: M
authors.lastname: Tanaka
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000473:pathology* / Q000601:surgery*; D000236:Adenoma / Q000473:pathology / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D021441:Carcinoma, Pancreatic Ductal / Q000473:pathology* / Q000601:surgery*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000473:pathology; D010183:Pancreatic Ducts / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000473:pathology* / Q000601:surgery*; D012189:Retrospective Studies