Colon (tumor & nontumor)
Other nonneoplastic

Topic Completed: 1 August 2013

Revised: 9 January 2019, last major update August 2013

Copyright: (c) 2003-2018,, Inc.

PubMed search: endometriosis [title] colon

Raul S. Gonzalez, M.D.
Page views in 2019: 1,602
Page views in 2020 to date: 1,085
Cite this page: Gonzalez R. Endometriosis. website. Accessed August 14th, 2020.
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

Images hosted on other servers:

Submucosal nodule

Microscopic (histologic) 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
Microscopic (histologic) images

Images hosted on other servers:

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
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