9 August 2006 Case of the Week #55


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We thank Dr. Jamie Shutter, George Washington University Medical Center, Washington, D.C. (USA) for contributing this case. This case was reviewed in May 2020 by Dr. Jennifer Bennett, University of Chicago and Dr. Carlos Parra-Herran, University of Toronto.


Case of the Week #55


Clinical history


The patient is an asymptomatic 50 year old woman with a radiographic submucosal mass at the ileocecal junction suspicious for carcinoma. An ileocolectomy was performed.


Microscopic images: low power #1, low power #2, medium power


What is your diagnosis?


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Endometriosis may present clinically with pain or obstruction, as a mass lesion, or be an incidental finding. In the bowel, it is rarely associated with neoplasms or premalignant change (AJSP 2000;24:513, Hum Path 2000;31:456, AJCP 1982;78:555)


Grossly, endometriosis typically presents as serosal or subserosal nodules 5 cm or less in size. The cut surface is gray with small areas of hemorrhage. Microscopically, there are typical endometrial glands and stroma with hemosiderin in deeper layers. The lesion is often surrounded by smooth muscle. The overlying bowel epithelium may have inflammation and ulcers simulating inflammatory bowel disease or solitary rectal ulcer syndrome, but is otherwise normal. There may also be fibrosis of the bowel wall or neuronal hypertrophy.


The clinical differential diagnoses included diverticulitis, appendicitis, inflammatory bowel disease, irritable bowel syndrome, tuboovarian abscess and malignancy (AJSP 2001;25:445). The histologic diagnosis is usually not difficult as long as one thinks of the diagnosis. If necessary, the endometrial stroma tests immunoreactive for CD10, and the endometrial glands are negative for CEA.



Nat Pernick, M.D.
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