Microscopic colitis and colorectal neoplastic lesion rate in chronic nonbloody diarrhea: A prospective, multicenter study

Gian Eugenio Tontini, Luca Pastorelli, Luisa Spina, Federica Fabris, Barbara Bruni, Claudio Clemente, Germana De Nucci, Flaminia Cavallaro, Stefano Marconi, Markus F. Neurath, Helmut Neumann, Milena Tacconi, Maurizio Vecchi

Research output: Contribution to journalArticlepeer-review


Background: Lymphocytic and collagenous colitis are emerging as common findings in subjects undergoing colonoscopy for chronic non-bloody diarrhea (CNBD). Data concerning microscopic colitis (MC) are still limited and affected by controversial epidemiological evidences. Recent converging lines of evidence suggest that MC correlates a lower risk of colorectal neoplasia. Accordingly, we prospectively assessed MC prevalence in a multicenter cohort of subjects submitted to colonoscopy for CNBD, thereby defining whether MC influences the risk of colorectal neoplasia. Methods: Consecutive patients with CNBD of unknown origin underwent pan-colonoscopy with multiple biopsies. The prevalence of neoplastic patients in MC was compared with that observed in negative CNBD subjects. Results: Among 8006 colonoscopy, 305 subjects were enrolled for CNBD. Patients with CNBD were more likely to be women than men (odds ratio = 1.5; P = 0.001). Histopathology detected high prevalence of MC (16%) with a clear predominance of collagenous colitis (70%). A striking agedependent rise in MC-associated risk was observed, depicting outstanding differences among varying age groups, as in the number needed to screen 1 new case. Gender distribution was balanced within MC patients (Female/Male = 1.5/1), especially among lymphocytic colitis (Female/Male = 1.2/1). MC patients were negatively associated with the risk of neoplastic polyps compared with negative CNBD subjects (odds ratio = 0.22; P = 0.035). Conclusions: MC is the first cause of CNBD in subjects submitted to colonoscopy. Multiple biopsies are strongly recommended, even in the case of uneventful endoscopic inspection, especially for age ≥40 years. MC has a reduced risk of colorectal neoplasia, suggesting that this model of chronic inflammation plays a protective effect against colorectal carcinogenesis.

Original languageEnglish
Pages (from-to)882-891
Number of pages10
JournalInflammatory Bowel Diseases
Issue number5
Publication statusPublished - 2014


  • Chronic nonbloody diarrhea
  • Collagenous colitis
  • Colonoscopy
  • Colorectal cancer
  • Microscopic colitis

ASJC Scopus subject areas

  • Gastroenterology
  • Immunology and Allergy
  • Medicine(all)


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