title: Predictors of malignancy and natural history of main-duct intraductal papillary mucinous neoplasms of the pancreas.
abstract: OBJECTIVE
  Because the prevalence of carcinoma is high in main-duct intraductal papillary mucinous neoplasms (IPMNs) of the pancreas, surgical resection is recommended for all main-duct type IPMNs. This study aimed to investigate the clinical predictors of malignancy and natural history of main-duct IPMNs.
  
  
  METHODS
  Preoperative clinical characteristics reliably correlated with malignancy in 26 surgically resected patients with main-duct IPMN, and long-term outcome in 20 conservatively followed patients with main-duct IPMN was examined.
  
  
  RESULTS
  Age at diagnosis was significantly older in conservatively followed IPMN patients than in surgically resected IPMN patients. Main pancreatic duct (MPD) dilatation 10 mm or greater and mural nodules were significantly more frequent in malignant IPMNs. Obvious progression of dilatation of the MPD was detected in all 4 conservatively followed patients who developed invasive pancreatic carcinoma. The histology of IPMN at autopsy of 4 conservatively followed patients who died of other causes 21 to 120 months later was adenoma. Seven conservatively followed without malignant findings did not show obvious progression of MPD dilatation.
  
  
  CONCLUSIONS
  Although surgical resection is indicated for many main-duct IPMNs, conservative follow-up may be an option for elderly asymptomatic patients with main-duct IPMNs with the MPD less than 10 mm, no obvious mural nodule, and negative cytology.
authors.affiliation: Department of Internal Medicine, Tokyo Metropolitan Komagome Hospital, Tokyo, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Takuma
authors.forename: Terumi
authors.initials: T
authors.lastname: Kamisawa
authors.forename: Hajime
authors.initials: H
authors.lastname: Anjiki
authors.forename: Naoto
authors.initials: N
authors.lastname: Egawa
authors.forename: Masanao
authors.initials: M
authors.lastname: Kurata
authors.forename: Goro
authors.initials: G
authors.lastname: Honda
authors.forename: Koji
authors.initials: K
authors.lastname: Tsuruta
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Horiguchi
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Igarashi
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis / Q000209:etiology* / 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 / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D011237:Predictive Value of Tests; D016896:Treatment Outcome