title: Over 90% of cases of Microscopic Colitis can be diagnosed by performing a short colonoscopy.
abstract: OBJECTIVE
  To determinate the topographical distribution of key diagnostic histological features of lymphocytic colitis (LC) and collagenous colitis (CC) and to establish what correlations may exist between the histological findings and the causes and severity of MC.
  
  
  METHODS
  Patients with MC were included in a prospective multicentre French study from September 2010 to October 2012. MC was diagnosed by performing total colonoscopy with multiple biopsies of the rectum and colon collected in separate jars and analyzed separately for each site (descending and sigmoid colon, transverse colon, ascending colon). CC was defined as a subepithelial collagen layer>10μm thick and LC as an intraepithelial lymphocyte (IEL) count>20 lymphocytes per 100 epithelial cells without any associated thickening of the subepithelial collagen.
  
  
  RESULTS
  Ninety-five patients, 69 with LC 26 and with CC, were included in the analysis. The sensitivity of the biopsies for diagnosing MC was maximum in the transverse colon and minimum in the rectum. Rectal and left colonic biopsies resulted in the diagnosis of CC and CL in 93% and 94% of cases, respectively. All the remaining cases of MC were diagnosed by performing additional biopsies beyond the splenic flexure. In patients with LC, a higher rate of IELs was associated with the absence of abdominal pain (P=0.01) and a shorter duration of diarrhea (P=0.001). In patients with CC, a lower level of collagen thickness in the basement membrane was associated with the presence of an autoimmune disease (P=0.02).
  
  
  CONCLUSIONS
  More than 90% of cases of microscopic colitis were diagnosed in this study by performing rectal and left colonic biopsies.
authors.affiliation: Service d'hépato-gastroentérologie, centre hospitalier de Marne-la-Vallée, 2-4, cours de la Gondoire, 77600 Jossigny, France. Electronic address: gmacaigne@ch-lagny77.fr.
authors.forename: Gilles
authors.initials: G
authors.lastname: Macaigne
authors.affiliation: Limeil Brévanne, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Lahmek
authors.affiliation: Meaux, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Locher
authors.affiliation: Service d'hépato-gastroentérologie, centre hospitalier de Marne-la-Vallée, 2-4, cours de la Gondoire, 77600 Jossigny, France.
authors.forename: Jean François
authors.initials: JF
authors.lastname: Boivin
authors.affiliation: Montfermeil, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Lesgourgues
authors.affiliation: Meaux, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Yver
authors.affiliation: Créteil, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Costes
authors.affiliation: Créteil, France.
authors.forename: I Abd
authors.initials: IA
authors.lastname: Alsamad
authors.affiliation: Montfermeil, France.
authors.forename: Joel
authors.initials: J
authors.lastname: Cucherousset
authors.affiliation: Villeneuve-Saint-Georges, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Charpignon
authors.affiliation: Villeneuve-Saint-Georges, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Guyot
authors.affiliation: Evry, France.
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Lambaré
authors.affiliation: Jolimont, Belgium.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Ghilain
authors.affiliation: Pau, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Calès
authors.affiliation: Aubagne, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: de Montigny-Lenhardt
authors.affiliation: Aulnay-sous-Bois, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Bellaïche
authors.affiliation: Pau, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Pariente
authors.affiliation: Montfermeil, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Nahon
mesh_terms: D001706:Biopsy; D046728:Colitis, Microscopic / Q000175:diagnosis* / Q000473:pathology; D044682:Colon, Ascending / Q000473:pathology*; D044683:Colon, Descending / Q000473:pathology*; D044684:Colon, Transverse / Q000473:pathology*; D003113:Colonoscopy; D005602:France; D006801:Humans; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity