title: Evaluation of magnifying colonoscopy in the diagnosis of serrated polyps.
abstract: OBJECTIVE
  To elucidate the colonoscopic features of serrated lesions of the colorectum using magnifying colonoscopy.
  
  
  METHODS
  Broad division of serrated lesions of the colorectum into hyperplastic polyps (HPs), traditional serrated adenomas (TSAs), and sessile serrated adenomas/polyps (SSA/Ps) has been proposed on the basis of recent molecular biological studies. However, few reports have examined the colonoscopic features of these divisions, including magnified colonoscopic findings. This study examined 118 lesions excised in our hospital as suspected serrated lesions after magnified observation between January 2008 and September 2011. Patient characteristics (sex, age), conventional colonoscopic findings (location, size, morphology, color, mucin) and magnified colonoscopic findings (pit pattern diagnosis) were interpreted by five colonoscopists with experience in over 1000 colonoscopies, and were compared with histopathological diagnoses. The pit patterns were categorized according to Kudo's classification, but a more detailed investigation was also performed using the subclassification [type II-Open (type II-O), type II-Long (type II-L), or type IV-Serrated (type IV-S)] proposed by Kimura T and Yamano H.
  
  
  RESULTS
  Lesions comprised 23 HPs (23/118: 19.5%), 39 TSAs (39/118: 33.1%: with cancer in one case), 50 SSA/Ps (50/118: 42.4%: complicated with cancer in three cases), and six others (6/118: 5.1%). We excluded six others, including three regular adenomas, one hamartoma, one inflammatory polyp, and one juvenile polyp for further analysis. Conventional colonoscopy showed that SSA/Ps were characterized as larger in diameter than TSAs and HPs (SSA/P vs HP, 13.62 ± 8.62 mm vs 7.74 ± 3.24 mm, P < 0.001; SSA/Ps vs TSA, 13.62 ± 8.62 mm vs 9.89 ± 5.73 mm, P < 0.01); common in the right side of the colon [HPs, 30.4% (7/23): TSAs, 20.5% (8/39): SSA/P, 84.0% (42/50), P < 0.001]; flat-elevated lesion [HPs, 30.4% (7/23): TSAs, 5.1% (2/39): SSA/Ps, 90.0% (45/50), P < 0.001]; normal-colored or pale imucosa [HPs, 34.8% (8/23): TSAs, 10.3% (4/39): SSA/Ps, 80% (40/50), P < 0.001]; and with large amounts of mucin [HPs, 21.7% (5/23): TSAs, 17.9% (7/39): SSA/Ps, 72.0% (36/50), P < 0.001]. In magnified colonoscopic findings, 17 lesions showed either type II pit pattern alone or partial type II pit pattern as the basic architecture, with 14 HPs (14/17, 70.0%) and 3 SSA/Ps. Magnified colonoscopy showed the type II-O pit pattern as characteristic of SSA/Ps [sensitivity 83.7% (41/49), specificity 85.7% (54/63)]. Cancer was also present in three lesions, in all of which a type VI pit pattern was also present within the same lesion. There were four HPs and four TSAs each. The type IV-S pit pattern was characteristic of TSAs [sensitivity 96.7% (30/31), specificity 89.9% (72/81)]. Cancer was present in one lesion, in which a type VI pit pattern was also present within the same lesion. In our study, serrated lesions of the colorectum also possessed the features described in previous reports of conventional colonoscopic findings. The pit pattern diagnosis using magnifying colonoscopy, particularly magnified colonoscopic findings using subclassifications of surface architecture, reflected the pathological characteristics of SSA/Ps and TSAs, and will be useful for colonoscopic diagnosis.
  
  
  CONCLUSIONS
  We suggest that this system could be a good diagnostic tool for SSA/Ps using magnifying colonoscopy.
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kawasaki 216-8511, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Ishigooka
authors.forename: Masahito
authors.initials: M
authors.lastname: Nomoto
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Obinata
authors.forename: Yoshichika
authors.initials: Y
authors.lastname: Oishi
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Sato
authors.forename: Satoko
authors.initials: S
authors.lastname: Nakatsu
authors.forename: Midori
authors.initials: M
authors.lastname: Suzuki
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Tadateru
authors.initials: T
authors.lastname: Maehata
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Kimura
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakajima
authors.forename: Hiro-o
authors.initials: HO
authors.lastname: Yamano
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yasuda
authors.forename: Fumio
authors.initials: F
authors.lastname: Itoh
mesh_terms: D000236:Adenoma / Q000175:diagnosis / Q000453:epidemiology; D000368:Aged; D003110:Colonic Neoplasms / Q000175:diagnosis / Q000453:epidemiology; D003111:Colonic Polyps / Q000145:classification* / Q000175:diagnosis* / Q000453:epidemiology; D003113:Colonoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011230:Precancerous Conditions / Q000175:diagnosis / Q000453:epidemiology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity