Anus & perianal area

Other nonneoplastic

Inflammatory cloacogenic polyp

Editorial Board Member: Naziheh Assarzadegan, M.D.
Deputy Editor-in-Chief: Catherine E. Hagen, M.D.
Nikka Khorsandi, M.D.
Kwun Wah Wen, M.D., Ph.D.

Last author update: 8 June 2023
Last staff update: 8 June 2023

Copyright: 2002-2023,, Inc.

PubMed Search: Inflammatory cloacogenic polyp

Nikka Khorsandi, M.D.
Kwun Wah Wen, M.D., Ph.D.
Page views in 2022: 10,146
Page views in 2023 to date: 14,016
Cite this page: Khorsandi N, Akarca FG, Wen KW. Inflammatory cloacogenic polyp. website. Accessed November 28th, 2023.
Definition / general
  • Benign polyp with colorectal, squamous and transitional epithelium with thickened and prolapsed muscularis mucosa associated with rectal prolapse
Essential features
  • Benign polyp with colorectal, squamous and transitional epithelium and prolapsed muscularis mucosae
  • Thought to be associated with mucosal prolapse or chronic inflammatory diseases
  • Located at anorectal transition zone
ICD coding
  • ICD-10: K62.0 - anal polyp
  • ICD-11: DB71 - inflammatory anal polyp
  • Wide age range from pediatric to adult population
  • Rectal mucosal prolapse due to repeated mucosal ischemia and regeneration are thought to contribute to the development (Histopathology 2008;53:91)
Clinical features
  • Patients sometimes present with a positive fecal immunochemical test (e.g., Cologuard)
Prognostic factors
Case reports
Clinical images

Images hosted on other servers:

Cloacogenic polyps on rectal retroflexion

Microscopic (histologic) description
  • Tubulovillous architecture with elongated crypts stretching into the submucosa
  • Areas of stratified squamous, colorectal or transitional epithelium that are often eroded and contain mixed inflammation and granulation tissue (Hum Pathol 1987;18:1120, Am J Surg Pathol 1981;5:761)
  • Abundant regenerative epithelial changes can be seen
  • Thickened muscularis mucosa with extension into the lamina propria
  • Fibromuscular obliteration of the lamina propria can be seen
Microscopic (histologic) images

Contributed by Nikka Khorsandi M.D., M.P.H., Kwun Wah Wen, M.D., Ph.D. and Yvonne Bury, M.D.
Squamous and glandular epithelium

Squamous and glandular epithelium

Surface erosion

Surface erosion

Mucosal erosion

Mucosal erosion

Regenerative epithelial changes

Regenerative epithelial changes

Sample pathology report
  • Anus, polypectomy:
    • Inflammatory cloacogenic polyp. Negative for dysplasia.
Differential diagnosis
Board review style question #1

Where is the lesion shown in the above image located?

  1. Anorectal transition zone
  2. Ascending colon
  3. Duodenum
  4. Rectum
  5. Stomach
Board review style answer #1
A. Inflammatory cloacogenic polyp is located in the anorectal transition zone.

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Reference: Inflammatory cloacogenic polyp
Board review style question #2
What is the preferred treatment for an inflammatory cloacogenic polyp?

  1. Chemotherapy
  2. Colectomy
  3. Endoscopic / surgical resection
  4. Fecal immunohistochemical test
  5. Routine endoscopic surveillance
Board review style answer #2
C. Endoscopic / surgical resection is the preferred treatment for an inflammatory cloacogenic polyp. Routine endoscopic surveillance is necessary after resection because of the risk of recurrence but it is not the treatment modality.

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Reference: Inflammatory cloacogenic polyp
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