title: Intraductal papillary mucinous neoplasms of the pancreas showing fistula formation into other organs.
abstract: BACKGROUND
  This study assessed the mechanism of fistula formation in intraductal papillary mucinous neoplasm (IPMN) of the pancreas.
  
  
  METHODS
  A total of 274 patients with IPMN who had been diagnosed by endoscopic retrograde cholangiopancreatography and endoscopic ultrasonography (EUS) at our center were enrolled. The patients with IPMN which had fistula formation into other organs were investigated retrospectively as to (1) clinical prevalence and the organs penetrated by IPMN, (2) analysis of the mechanism of fistula formation by immunohistopathological study, (3) efficacy of EUS in progression assessment, and (4) prognosis.
  
  
  RESULTS
  Among the subjects, fistula formation into other organs was observed in 18 patients (6.6%) and into 28 organs. There were 7 patients (39%) in whom multiple organs were penetrated. Of 16 patients who had undergone investigation of the expression of mucin markers, 94% had an intestinal-type tumor. Of 9 patients who had undergone surgery or autopsy, 67% showed mechanical penetration without invasion around the fistula. Only papillary protrusions were seen by EUS in 4 of these patients with noninvasive papillary adenocarcinoma showing mechanical penetration. All 5 patients who had pancreatic parenchymal invasion showed a mass with a mixed-echo pattern in addition to papillary protrusions shown by EUS, corresponding to colloid carcinoma.
  
  
  CONCLUSIONS
  There were 2 processes in the development of fistulas in IPMN. Of those patients showing fistula formation, 94% had intestinal-type IPMN, and 67% showed mechanical penetration. Delineation of a mass with the mixed-echo pattern suggested an invasive penetration due to colloid carcinoma.
authors.affiliation: Department of Gastroenterology, Sendai City Medical Center, 5-22-1 Tsurugaya, Miyagino-ku, Sendai, Miyagi, Japan. go-koba@mua.biglobe.ne.jp
authors.forename: Go
authors.initials: G
authors.lastname: Kobayashi
authors.forename: Naotaka
authors.initials: N
authors.lastname: Fujita
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Noda
authors.forename: Kei
authors.initials: K
authors.lastname: Ito
authors.forename: Jun
authors.initials: J
authors.lastname: Horaguchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Obana
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Koshida
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Kanno
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Yamashita
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Kato
authors.forename: Takahisa
authors.initials: T
authors.lastname: Ogawa
authors.forename: Masaya
authors.initials: M
authors.lastname: Oikawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuchiya
authors.forename: Takashi
authors.initials: T
authors.lastname: Sawai
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000150:complications* / Q000473:pathology; D000368:Aged; D000369:Aged, 80 and over; D021441:Carcinoma, Pancreatic Ductal / Q000150:complications* / Q000473:pathology; D002291:Carcinoma, Papillary / Q000150:complications* / Q000473:pathology; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000379:methods; D019160:Endosonography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010185:Pancreatic Fistula / Q000453:epidemiology / Q000209:etiology / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000150:complications* / Q000473:pathology; D015995:Prevalence; D011379:Prognosis; D012189:Retrospective Studies