title: Clinicopathologic and endoscopic features of colorectal serrated adenoma: differences between polypoid and superficial types.
abstract: BACKGROUND
  Serrated adenoma is a distinct histologic colorectal lesion. There are two macroscopic types: polypoid and superficial. The aim of this study was to clarify clinicopathologic and endoscopic differences between polypoid and superficial serrated adenomas.
  
  
  METHODS
  An analysis was conducted of the clinicopathologic and endoscopic features for 240 polypoid and 127 superficial serrated adenomas examined by colonoscopy, and the surface pit patterns of 114 polypoid and 64 superficial serrated adenomas examined by magnifying videoendoscopy.
  
  
  RESULTS
  The male:female gender ratio for the polypoid serrated adenomas (3.5:1) was significantly higher than that for the superficial serrated adenomas (1.7:1). Superficial serrated adenomas were significantly larger than polypoid serrated adenomas (mean [standard deviation], respectively, 10.1 [7.9] mm vs. 6.3 [4.6] mm). In the distal segments of the colorectum, polypoid serrated adenomas were more common than superficial serrated adenomas. Granulonodular and lobular appearances at endoscopy were significantly more common for polypoid (23.3%) than for superficial serrated adenomas (7.1%). Pit patterns differed between the lesion types: polypoid serrated adenomas had type III(L) or IV pit patterns; all superficial serrated adenomas had the type II pit pattern. The relative frequency of occurrence of high-grade dysplasia and carcinoma in situ among superficial serrated adenomas (25.2%) was significantly greater than that among polypoid serrated adenomas (9.2%). The tubulovillous growth pattern was significantly more common in polypoid tumors (31.5%) than in superficial tumors (0%).
  
  
  CONCLUSIONS
  Polypoid and superficial serrated adenomas have different clinicopathologic characteristics and growth patterns.
authors.affiliation: Department of Endoscopy, Department of Medicine and Molecular Science, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Oka
authors.forename: Shinji
authors.initials: S
authors.lastname: Tanaka
authors.forename: Toru
authors.initials: T
authors.lastname: Hiyama
authors.forename: Masanori
authors.initials: M
authors.lastname: Ito
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kitadai
authors.forename: Masaharu
authors.initials: M
authors.lastname: Yoshihara
authors.forename: Ken
authors.initials: K
authors.lastname: Haruma
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Chayama
mesh_terms: D000236:Adenoma / Q000473:pathology*; D018256:Adenomatous Polyps / Q000473:pathology*; D000328:Adult; D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged