title: Clinicopathologic differences among subtypes of serrated adenomas of the colorectum.
abstract: OBJECTIVE
  Serrated adenomas (SAs) of the colorectum can be broadly divided into two subtypes: type I more closely mimicking hyperplastic polyps, and type II unequivocal traditional adenomas. The aim of this study was to clarify their differential clinicopathologic and colonoscopic features.
  
  
  METHODS
  A total of 127 SAs (53 type I, 52 type II and 22 admixed type I+II) were investigated and colonoscopic surface patterns were divided into three categories: speckled, granular and cerebriform.
  
  
  RESULTS
  The cerebriform pattern was most frequently observed in all SA types. Types I+II (median size, 7.5 mm) or type II SAs (median size, 10 mm) were generally sessile or pedunculated polyps in the rectosigmoid colon whereas some type I lesions (median size, 5 mm) demonstrated a flat-elevated morphology and were found in the ascending colon and cecum. Co-existing (2/127: 1.6%) invasive carcinomas were only detected with type II SAs. In contrast, synchronous invasive carcinomas distant from SAs were more frequently observed with type I (31%) than types I+II (5%) or II (12%).
  
  
  CONCLUSIONS
  Clinicopathologic differences are apparent among the types of SAs. A type II SA-invasive carcinoma sequence might exist. We stress recognition of type I SA as a neoplastic, rather than a hyperplastic lesion, often accompanying invasive carcinomas at a distance from the SA.
authors.affiliation: Department of Internal Medicine, School of Medicine, Kitasato University East Hospital, Sagamihara, Kanagawa, Japan. miwa-s@kitasato-u.ac.jp
authors.forename: Sada
authors.initials: S
authors.lastname: Miwa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mitomi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Igarashi
authors.forename: Kiyonori
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Tomoe
authors.initials: T
authors.lastname: Katsumata
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ihara
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Otani
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ojima
authors.forename: Katsunori
authors.initials: K
authors.lastname: Saigenji
mesh_terms: D000236:Adenoma / Q000473:pathology* / Q000503:physiopathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000473:pathology; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009378:Neoplasms, Multiple Primary / Q000473:pathology