Colon non tumor
Nonneoplastic, noncongenital lesions

Author: Raul S. Gonzalez, M.D. (see Authors page)

Revised: 10 November 2016, last major update August 2013

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

PubMed search: endometriosis [title] colon

Cite this page: Endometriosis. website. Accessed March 29th, 2017.
Definition / General
  • Endometriosis arising within colon
  • Up to 1 / 3 with endometriosis have involvement of large or small intestine
  • Usually rectosigmoid or rectovaginal septum (Med Sci Monit 2000;6:787); can involve any portion of colonic wall, from mucosa to serosa
Clinical Features
  • Typically incidental but can cause pain, obstruction, or diarrhea
  • Rarely associated with neoplasms or precancerous changes (Am J Surg Pathol 2000;24:513)
Case Reports
Gross Description
  • Serosal and subserosal nodules < 5 cm; smooth muscle hypertrophy may cause obstruction
  • Gray cut surface with minute areas of hemorrhage; can cause adhesions if subserosal
Gross Images
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Submucosal nodule

Micro Description
  • Endometrial glands and stroma plus hemosiderin in deeper layers of colon; usually surrounded by smooth muscle
  • Epithelium may have inflammation and ulcers, simulating inflammatory bowel disease or solitary rectal ulcer syndrome
  • Often infiltrates along nerves of bowel wall (Hum Reprod 2004;19:996)
  • Mucosa usually normal; bowel wall may be fibrotic; cilia help distinguish endometrial glands from colonic glands
Micro Images
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Implants within bowel muscle

Within colonic mucosa

Present in wall of colon

Infiltration along nerves

In pericolic lymph nodes (figures 3 / 4)

Positive Stains
Negative Stains
Differential Diagnosis