title: Invasive carcinoma derived from "flat type" branch duct intraductal papillary mucinous neoplasms of the pancreas: impact of classification according to the height of mural nodule on endoscopic ultrasonography.
abstract: BACKGROUND
  It has been reported that many branch duct intraductal papillary mucinous neoplasms (BD-IPMN) with a mural nodule (MN) reveal adenocarcinomas. On the other hand, invasive cancer derived from BD-IPMN without MN on endoscopic ultrasound (EUS) also exists. The aim of this study was to elucidate the clinicopathological features of invasive cancer derived from BD-IPMN without MN on EUS.
  
  
  METHODS
  Twenty-one patients pathologically diagnosed with invasive cancer derived from BD-IPMN were included in this study.
  
  
  RESULTS
  Based on the height of MNs on EUS, the subjects could be clearly classified as 12 patients whose background BD-IPMNs had high MNs (nodule-forming type IPMN) and nine whose background BD-IPMNs showed no MNs (flat type IPMN). The background BD-IPMN of the 12 patients with nodule-forming type IPMN were non-gastric type. On the other hand, the background BD-IPMN of the nine patients with flat type IPMN was gastric type. The recurrence rate was higher (33% vs. 67%) and the 5-year survival was worse (76% vs. 33%) in flat type IPMN.
  
  
  CONCLUSIONS
  There may be a pathway for the development of invasive cancer without the formation of an MN in BD-IPMN, and attention should be paid even to the patients with BD-IPMN which does not present an MN.
authors.affiliation: Department of Gastroenterology, Sendai City Medical Center, 5-22-1 Tsurugaya, Miyagino-ku, Sendai, 983-0824, Japan. skoshita@openhp.or.jp.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Koshita
authors.forename: Naotaka
authors.initials: N
authors.lastname: Fujita
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Noda
authors.forename: Go
authors.initials: G
authors.lastname: Kobayashi
authors.forename: Kei
authors.initials: K
authors.lastname: Ito
authors.forename: Jun
authors.initials: J
authors.lastname: Horaguchi
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Kanno
authors.forename: Takahisa
authors.initials: T
authors.lastname: Ogawa
authors.forename: Kaori
authors.initials: K
authors.lastname: Masu
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Michikawa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Iwashita
authors.forename: Takashi
authors.initials: T
authors.lastname: Sawai
authors.forename: Miwa
authors.initials: M
authors.lastname: Uzuki
authors.forename: Fumiyoshi
authors.initials: F
authors.lastname: Fujishima
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000145:classification* / Q000000981:diagnostic imaging / Q000556:secondary; D000368:Aged; D021441:Carcinoma, Pancreatic Ductal / Q000145:classification* / Q000000981:diagnostic imaging / Q000556:secondary; D003937:Diagnosis, Differential; D019160:Endosonography / Q000379:methods*; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D009367:Neoplasm Staging / Q000379:methods*; D010190:Pancreatic Neoplasms / Q000145:classification* / Q000000981:diagnostic imaging; D012189:Retrospective Studies
keywords: Endoscopic ultrasound; Flat type; Intraductal papillary mucinous neoplasms; Invasive carcinoma; Mural nodule