Table of ContentsDefinition / general | Essential features | Epidemiology | Sites | Clinical features | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosis | Sample pathology report | Board review style question #1 | Board review style answer #1
Cite this page: Gonzalez RS. Endometriosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colonendometriosis.html. Accessed May 12th, 2021.
Definition / general
- Endometriosis arising within colon
- Similar to endometriosis elsewhere: can cause clinical symptoms; histology shows endometrial glands, endometrial stroma and hemosiderin
- Malignant transformation is rare
- Up to 33% 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
- Typically incidental but can cause pain, obstruction or diarrhea
- Rarely associated with neoplasms or precancerous changes (Am J Surg Pathol 2000;24:513)
- 31 year old patient with schistosomiasis (Fertil Steril 2006;85:1060.e1)
- 35 year old woman with obstruction of sigmoid colon (Ugeskr Laeger 2005;167:3604)
- 42 year old woman with mixed germ cell tumor (Am J Clin Pathol 1982;78:555)
- 48 year old woman with endometrial stroma sarcoma (J Korean Med Sci 2002;17:412)
- 65 year old woman with clear cell carcinoma (J Clin Pathol 2001;54:76)
- With endometrioid adenocarcinoma (Am Surg 2005;71:694)
- Pain medication, hormonal therapy; may require surgery if causing obstructive symptoms (Clin Colon Rectal Surg 2010;23:72)
- 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
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
Sample pathology report
- Ascending colon, resection:
- Colon with multiple mural and serosal foci of endometriosis
- Negative for malignancy.
- Margins of resection unremarkable.
- Two benign lymph nodes.
Board review style question #1