Colon

Other nonneoplastic

Idiopathic myointimal hyperplasia of mesenteric veins



Topic Completed: 26 February 2021

Minor changes: 5 March 2021

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PubMed Search: Idiopathic myointimal hyperplasia of mesenteric veins

Raul S. Gonzalez, M.D.
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Cite this page: Gonzalez RS. Idiopathic myointimal hyperplasia of mesenteric veins. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colonmyointimalhyperplasia.html. Accessed October 28th, 2021.
Definition / general
  • Unusual thickening of mesenteric veins, resulting in gastrointestinal symptoms and ischemic colitis
Essential features
  • Rare condition that clinically mimics inflammatory bowel disease in young men
  • Thought to result from arteriovenous fistulization
  • Histology: hyperplastic veins mimic arteries (distinguish with elastin stain); thick walled vascular proliferation in mucosa
Epidemiology
Sites
  • Usually (but not always) involves the left colon
Etiology
Clinical features
  • Diarrhea / constipation, abdominal pain, rectal bleeding
Case reports
Treatment
  • Surgery usually required
Microscopic (histologic) description
  • Biopsy findings: ischemic mucosal change accompanied by proliferation of hyperplastic, thick walled, hyalinized blood vessels (Am J Surg Pathol 1996;20:1271)
  • Resection findings: mesenteric and mural veins show myointimal hyperplasia, making them somewhat resemble arteries; no vasculitis present; arteries are unaffected (Gastroenterology 1991;101:533)
Microscopic (histologic) images

Contributed by Raul S. Gonzalez, M.D.

Biopsy: mucosal
proliferation
of thick walled
vessels

Resection:
thickened
mural veins

2 thickened veins and 1 unaffected artery

Elastin stain
highlights
internal elastic
lamina of artery

Positive stains
  • Elastin stain confirms that blood vessels with myointimal hyperplasia are veins, not arteries
Sample pathology report
  • Descending colon, resection:
    • Segment of colon with prominent vascular reactive changes and myointimal hyperplasia of mesenteric veins (see comment)
    • Margins of resection unremarkable.
    • Seven benign lymph nodes.
    • Comment: There is no definitive evidence of chronic colitis. An elastic special stain highlights mesenteric veins with myointimal hyperplasia, distinguishing them from arteries.
Differential diagnosis
  • Inflammatory bowel disease:
    • Similar clinical picture but histology shows a classic chronic colitis, without vascular abnormalities
  • Mesenteric phlebosclerosis:
    • Unusual vascular disease seen only in Japanese patients; mesenteric and colonic mucosal vessels are calcified and sclerotic (Dis Colon Rectum 2003;46:209)
Board review style question #1

Which of the following is true about idiopathic myointimal hyperplasia of mesenteric veins?

  1. An elastin stain can help distinguish arteries from abnormal veins
  2. Histologic changes are seen in resection but not biopsy specimens
  3. It classically occurs along the right colon in older female patients
  4. It is asymptomatic and incidentally observed
Board review style answer #1
A. An elastin stain can help distinguish arteries from abnormal veins

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