Colon non tumor
Colitis (non-infectious)
Collagenous colitis

Author: Hanni Gulwani, M.D. (see Authors page)

Revised: 26 December 2016, last major update May 2013

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: collagenous colitis
Cite this page: Collagenous colitis. PathologyOutlines.com website. http://pathologyoutlines.com/topic/coloncollagenous.html. Accessed September 21st, 2017.
Definition / general
  • Disorder of chronic watery diarrhea and crampy abdominal pain with normal colonoscopy and barium enema; due to inflammation and patchy thickening of subepithelial basement membrane (eMedicine - Collagenous and Lymphocytic Colitis)
  • May represent similar entity as lymphocytic colitis, but is clearly distinct from inflammatory bowel disease (Gastroenterol Clin Biol 2008;32:689)
  • Pseudomembranous collagenous colitis: morphologic variant in which active inflammation with pseudomembrane formation is prominent; various etiologies (Ann Diagn Pathol 2013;17:291)
Epidemiology
  • 85% in elderly women, often smokers
  • Most cases in Western countries, rare in Asia or Africa
Pathophysiology
  • Upregulation of nitric oxide synthase activity leads to increased production of nitric oxide in colonic mucosa, which may cause diarrhea
  • Diarrhea is secretory and has components of decreased sodium chloride absorption and active chloride secretion
  • Severity of diarrhea correlates with inflammation, not thickness of collagen deposits (Arch Pathol Lab Med 2010;134:1485)
Clinical features
Children and adolescents
  • Rare; similar clinical presentation, with female preponderance, presentation with diarrhea and abdominal pain, association with celiac disease and other autoimmune disorders
  • Differences from adults: children have weight loss; either alternating constipation and diarrhea, constipation alone or normal bowel movements
  • Treatment less standardized (Mod Pathol 2013;26:881)
Case reports
Treatment
Clinical images

Images hosted on other servers:

Colonoscopy

Sessile, ‘carpet-like’
polypoid lesion

Microscopic (histologic) description
  • Patchy thickening of subepithelial basement membrane of 10 microns or more (thickest in transverse colon); often spares rectosigmoid; lower border of collagen is irregular, extends into lamina propria and encircles capillaries, may be difficult to measure
  • Also increased chronic inflammatory cells (lymphocytes, plasma cells, eosinophils) in lamina propria and within surface epithelium (20+ lymphocytes per 100 epithelial cells)
  • Epithelial damage is demonstrated by loss of mucin and irregular orientation of nuclei
  • Usually no neutrophilic infiltration, no atrophy, no mucosal architectural distortion
  • 6+ intraepithelial lymphocytes per 100 epithelial cells in terminal ileum is 98% specific and 50 - 60%sensitive for collagenous/lymphocytic colitis (Am J Surg Pathol 2002;26:1484)
  • Increased connective tissue growth factor expression; may be end stage mediator of local fibrosis (Histopathology 2010;57:427)
  • Diagnosis: do not base on thickness of collagen, but distorted superficial cell arrangement with areas of epithelial denudation and inflammatory cells in superficial epithelium and the lamina propria; in agreement with Lazenby's statement: "Focusing solely on the collagen band can result in both over- and underdiagnosis" (Am J Clin Pathol 2008;130:375)
Microscopic (histologic) images

Images hosted on other servers:

Increased subepithelial collagen


Trichrome


Various images #1

#2

#3

With giant cells

Positive stains
  • Trichrome (recommended, rules out amyloid deposition)
Differential diagnosis
  • Chronic ischemic damage: fibrosis in lamina propria
  • Lymphocytic colitis: no collagen
  • Nonspecific changes
  • Scleroderma: affects muscularis propria
  • Solitary rectal ulcer syndrome: mucosal architectural distortion, variable collagen deposits but no intraepithelial lymphocytes
  • Tangential sectioning of subepithelial basement membrane (lacks inflammation)