title: Colonoscopic features and malignant potential of sessile serrated adenomas: comparison with other serrated lesions and conventional adenomas.
abstract: OBJECTIVE
  Sessile serrated adenomas/polyps (SSA/Ps) have been proposed as precursors of colorectal cancer. The aims of this investigation were to compare the endoscopic findings of SSA/Ps with those of other serrated lesions and to compare the histological findings of SSA/Ps with those of conventional adenomas.
  
  
  METHODS
  We retrospectively reviewed colonoscopy records at our institution from 1984 to 2013 and identified cases of endoscopically or surgically resected conventional adenomas and serrated lesions, including SSA/Ps, hyperplastic polyps (HPs) and traditional serrated adenomas (TSAs). The colonoscopic findings of SSA/Ps were compared with those of the other two serrated lesions and histological findings were compared among all groups of lesions.
  
  
  RESULTS
  There were 79 HPs in 68 patients, 77 SSA/Ps in 63 patients, 167 TSAs in 145 patients and 6324 conventional adenomas in 4129 patients. The inverted type and flat-elevated type were more frequent among SSA/Ps than among the other two types of serrated lesions. Magnifying colonoscopy revealed that a round and open pit pattern, expanded crypt openings and varicose microvascular vessels were more frequently observed among SSA/Ps than among the other types. The incidence of high-grade dysplasia or carcinoma among SSA/Ps (13.0%) was significantly higher than that among HPs (0%, P < 0.001) and equivalent to that among conventional adenomas (12.3%).
  
  
  CONCLUSIONS
  SSA/Ps have colonoscopic features distinct from those of HPs and TSAs. The malignant potential of SSA/Ps seems to be equal to that of conventional adenomas.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Iwate Medical University, Morioka, Japan.|Division of Gastroenterology, Matsuyama Red Cross Hospital, Matsuyama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kawasaki
authors.affiliation: Division of Gastroenterology, Matsuyama Red Cross Hospital, Matsuyama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kurahara
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Iwate Medical University, Morioka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Yanai
authors.affiliation: Department of Pathology, Matsuyama Red Cross Hospital, Matsuyama, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Oshiro
authors.affiliation: Department of Human Pathology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yao
authors.affiliation: Division of Gastroenterology, Fukuoka Sanno Hospital, Fukuoka, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kobayashi
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Iwate Medical University, Morioka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Division of Gastroenterology, Matsuyama Red Cross Hospital, Matsuyama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Fuchigami
authors.affiliation: Department of Diagnostic Pathology, Iwate Medical University, Morioka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Sugai
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Iwate Medical University, Morioka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
mesh_terms: D000230:Adenocarcinoma / Q000098:blood supply / Q000150:complications / Q000473:pathology*; D000236:Adenoma / Q000098:blood supply / Q000150:complications / Q000473:pathology*; D000368:Aged; D003106:Colon / Q000473:pathology; D003111:Colonic Polyps / Q000473:pathology*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000098:blood supply / Q000150:complications / Q000473:pathology*; D005260:Female; D006801:Humans; D006965:Hyperplasia; D008297:Male; D055806:Microvessels / Q000473:pathology*; D008875:Middle Aged; D012189:Retrospective Studies
keywords: Colonoscopy; hyperplastic polyp; sessile serrated adenoma/polyp; traditional serrated adenoma