Colon
Noninfectious colitis
Collagenous colitis


Topic Completed: 3 August 2020

Minor changes: 29 September 2020

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PubMed Search: Collagenous colitis[TI] review[PT]

Benjamin J. Van Treeck, M.D.
Catherine E. Hagen, M.D.
Page views in 2019: 9,876
Page views in 2020 to date: 9,090
Cite this page: Van Treeck BJ, Hagen CE. Collagenous colitis. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/coloncollagenous.html. Accessed October 26th, 2020.
Definition / general
  • Form of microscopic colitis clinically associated with chronic watery diarrhea and histologically characterized by colonic intraepithelial lymphocytosis, surface mucosal damage, lamina propria inflammation and a subepithelial collagen band
Essential features
  • Subtype of microscopic colitis in which patients present with chronic watery diarrhea and normal or nearly normal endoscopic findings
  • Pathophysiology and etiology are unclear but thought to be multifactorial with a possible luminal antigen triggering inflammation and mucosal damage in a genetically predisposed individual
  • Histology is characterized by a subepithelial collagen band, intraepithelial lymphocytosis, mixed inflammation in the lamina propria and surface mucosal damage with preserved crypt architecture
ICD coding
  • ICD-10: K52.831 - Collagenous colitis
Epidemiology
Sites
Pathophysiology
  • Poorly understood
  • Presumed mechanism includes a dysregulated immune reaction to an unknown luminal antigen (medication, dietary factor, infectious agent, other) in a genetically predisposed individual (Lancet Gastroenterol Hepatol 2019;4:305)
  • Watery diarrhea is a result of inhibited sodium channel upregulation, downregulation of tight junctions and colonocyte aquaporins and bile acid malabsorption (Lancet Gastroenterol Hepatol 2019;4:305)
Etiology
  • Strong association with certain medications
    • NSAIDs, aspirin, proton pump inhibitors, H2 receptor antagonists, selective serotonin reuptake inhibitors, among others (Am J Gastroenterol 2017;112:78)
  • Other specific etiologies are unknown
Clinical features
Diagnosis
Prognostic factors
Case reports
Treatment
  • Discontinuation of any offending medications (Am J Gastroenterol 2017;112:78)
  • Antidiarrheals such as loperamide, diphenoxylate or bismuth subsalicylate
  • For more severe symptoms, corticosteroids such as budesonide can be used
  • Surgical intervention is a last resort
Clinical images

Images hosted on other servers:

Mucosal tears

Endoscopic findings

Microscopic (histologic) description
  • Thickened subepithelial collagen band, usually with capillary, red blood cell and inflammatory cell entrapment (Histopathology 2015;66:613)
    • Collagen band typically > 10 microns
    • Occasional cases can have an irregular collagen band that is < 10 microns; some have labeled such cases as "incomplete collagenous colitis"
    • Trichrome stain can be useful in equivocal cases
  • Surface mucosal damage with loss of mucin, flattening and detachment
  • Increased lamina propria inflammation composed of lymphocytes, plasma cells and eosinophils
    • Neutrophilic inflammation can be seen but is typically not prominent
  • Increased intraepithelial lymphocytes; may be mild (< 20 per 100 epithelial cells)
  • Crypt architecture is preserved or minimally distorted
  • Subepithelial multinucleated giant cells can be seen but have no clinical significance (Pathology 2008;40:671)
  • Pseudomembranous collagenous colitis has been described; unclear whether truly a variant of collagenous colitis or due to superimposed infection or medication injury (Dig Dis Sci 2004;49:1763, Pathol Res Pract 2013;209:735)
Microscopic (histologic) images

Contributed by Catherine E. Hagen, M.D.
Preserved architecture

Preserved architecture

Thickened subepithelial collagen

Thickened subepithelial collagen

Epithelial detachment

Epithelial detachment

Equivocal collagen

Equivocal collagen

Trichrome stain

Trichrome stain

Giant cell

Giant cell


Crypt atrophy

Crypt atrophy

Virtual slides

Images hosted on other servers:

Collagenous colitis biopsy

Positive stains
Negative stains
Sample pathology report
  • Colon, random, biopsies:
    • Colonic mucosa with a thickened subepithelial collagen band, increased intraepithelial lymphocytes and surface epithelial injury, consistent with collagenous colitis
Differential diagnosis
  • Lymphocytic colitis:
    • Lack of subepithelial collagen band and greater number of intraepithelial lymphocytes
  • Inflammatory bowel disease:
    • Lack of subepithelial collagen band
    • Architectural distortion and prominent neutrophilic inflammation
    • Endoscopic evidence of inflammation and clinical history of bloody diarrhea
  • Chronic ischemic colitis:
    • Diffuse lamina propria hyalinization as opposed to a discrete subepithelial collagen band
    • Withered, injured crypts
  • Amyloidosis:
    • Usually surrounds blood vessels, though rarely may create a subepithelial layer mimicking collagenous colitis
    • Congo red stain is positive
    • Lack of surface epithelial injury and inflammation
Board review style question #1

A 55 year old female with a 1 year history of chronic watery diarrhea presents for evaluation. Stool ova / parasites and culture are negative for infectious organisms. Colonoscopy is performed and reveals a grossly normal appearing colon. The biopsy histology is shown. Which of the following diagnoses is correct?

  1. Collagenous colitis
  2. Crohn's colitis
  3. Irritable bowel syndrome
  4. Lymphocytic colitis
Board review answer #1
A. Collagenous colitis

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Reference: Collagenous colitis
Board review style question #2
A 57 year old female was recently diagnosed with collagenous colitis. Which of the following is a characteristic histologic feature of collagenous colitis?

  1. Architectural distortion
  2. Cryptitis and crypt abscess
  3. Granulomas
  4. Mixed lamina propria inflammation
Board review answer #2
D. Mixed lamina propria inflammation

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Reference: Collagenous colitis
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