title: Endoscopic features and management of diminutive colorectal submucosal invasive carcinoma.
abstract: OBJECTIVE
  The vast majority of diminutive (∼5 mm) colorectal tumors consist of a very low prevalence of advanced neoplasia, and a predict-resect-and-discard policy has been proposed recently in Western countries. The histology of some diminutive colorectal tumors reveals carcinoma, not adenoma, although the frequency is relatively low. Clarifying the endoscopic features of diminutive submucosal invasive colorectal carcinoma (CRC) during colonoscopy is important for managing diminutive lesions.
  
  
  METHODS
  A total of 111 cases of submucosal invasive CRC ≤ 10 mm were analyzed. The incidence of submucosal invasion in early CRC per gross type, size, location, pit pattern diagnosis, and rate of lymph node (LN) metastasis was evaluated.
  
  
  RESULTS
  In diminutive tumors, the overall submucosal invasion rate in early CRC was 9.6%; however, depressed tumors had a significantly higher frequency of submucosal invasion than protruded or flat elevated tumors. There were no significant differences in the distribution of submucosal invasive CRC between the diminutive tumors and those that were 6-10 mm. The pit pattern diagnosis of diminutive submucosal invasive CRC was type VI pit pattern in all cases. Each case of submucosal invasive CRC was completely resected by en bloc endoscopic resection, and there were no cases of LN metastasis.
  
  
  CONCLUSIONS
  Diminutive tumors with depression have a high frequency of submucosal invasive CRC and an initial indication for endoscopic resection.
authors.affiliation: Department of Endoscopy, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Oka
authors.forename: Shinji
authors.initials: S
authors.lastname: Tanaka
authors.forename: Koichi
authors.initials: K
authors.lastname: Nakadoi
authors.forename: Naoki
authors.initials: N
authors.lastname: Asayama
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Chayama
mesh_terms: D000236:Adenoma / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery; D017677:Age Distribution; D000368:Aged; D015331:Cohort Studies; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000473:pathology* / Q000601:surgery; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D015995:Prevalence; D012189:Retrospective Studies; D018570:Risk Assessment; D017678:Sex Distribution
keywords: colon and rectum; diminutive tumor; endoscopic feature; pit pattern; submucosal invasive carcinoma