title: Cyst growth rate predicts malignancy in patients with branch duct intraductal papillary mucinous neoplasms.
abstract: OBJECTIVE
  Little information is available about the clinico-pathologic characteristics of pancreatic branch duct intraductal papillary mucinous neoplasm (Br-intraductal papillary mucinous neoplasm [IPMN]) because of difficulties in diagnosis based on radiologic and tissue information. We investigated the natural history of Br-IPMN using imaging and surgical pathology data from patients.
  
  
  METHODS
  Data were collected from patients admitted to a single tertiary referral institution from January 2000 to March 2009 (median follow up of 27.9 months); 201 patients were diagnosed with Br-IPMN with an initial cyst less than 30 mm without main pancreatic duct dilatation or mural nodules. The patients were followed for more than 3 months and examined by computed tomography (CT) at least twice.
  
  
  RESULTS
  The mean size of the patients' initial cysts was 14.7 mm; the mean cyst growth rate was 1.1 mm/year. Thirty-five patients received surgery during follow up and 8 were confirmed to have malignant cysts. The malignant cysts were greater in final size than nonmalignant cysts (24.3 mm vs 16.9 mm; P = .003); they also grew by a greater percentage (69.8% vs 19.4%; P = .046) and at a greater rate (4.1 mm vs 1.0 mm/year; P = .001). The actuarial 5-year risk of malignancy was 41.6% in the group that received surgery and 10.9% for all patients. Cysts that grew more than 2 mm/year had a higher risk of malignancy (5-year risk = 45.5% vs 1.8%; P < .001).
  
  
  CONCLUSIONS
  In combination with cyst size and the presence of mural nodules, cyst growth rate could be used to predict malignancy in patients with Br-IPMN.
authors.affiliation: Department of Surgery and Cancer Research Institute, Seoul National University College of Medicine, Seoul, South Korea.
authors.forename: Mee Joo
authors.initials: MJ
authors.lastname: Kang
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Jang
authors.forename: Soo Jin
authors.initials: SJ
authors.lastname: Kim
authors.forename: Kyoung Bun
authors.initials: KB
authors.lastname: Lee
authors.forename: Ji Kon
authors.initials: JK
authors.lastname: Ryu
authors.forename: Yong-Tae
authors.initials: YT
authors.lastname: Kim
authors.forename: Yong Bum
authors.initials: YB
authors.lastname: Yoon
authors.forename: Sun-Whe
authors.initials: SW
authors.lastname: Kim
mesh_terms: D000368:Aged; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology*; D018282:Cystadenocarcinoma, Mucinous / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology*; D018283:Cystadenocarcinoma, Papillary / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000000981:diagnostic imaging / Q000473:pathology; D011379:Prognosis; D014056:Tomography, X-Ray