Duodenum

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The duodenum is the first part of the small bowel. It is accessible by EGD (esophagogastroduodenoscopy) and frequently biopsied.

The clinical history is often: r/o celiac or r/o giardia.

Getting started

  • Celiac
    • Loss of villi.
    • Intraepithelial lymphocytes.
  • Giarrdia
    • Like celiac... but giarrdia organisms.
  • Adenomas
    • Too much blue - similar to colonic adenomas.
  • Cancer
    • Too much blue and epithelium in the wrong place.

Celiac sprue

Etiology

  • Autoimmune.

Serology

  • Anti-transglutaminase antibody.
    • Alternative test: anti-endomysial antibody.

Epidemiology

  • Associated with:
    • The skin condition dermatitis herpetiformis.[1]
      • Tx: dapsone.
    • IgA deficiency - 10-15X more common in celiac disease vs. healthy controls.[2]
    • Risk factor for gastrointestinal T cell lymphoma - known as: enteropathy-associated T cell lymphoma (EATL).

Histology

Features:[3]

  • Enteritis.
    • Intraepithelial lymphocytes - key feature.
    • Plasma cells.
    • Macrophages.
  • Loss of villi - key feature.
    • Normal duodenal biopsy should have 3 good villi.
  • Mitosis increased (in the crypts).

Notes:

  • If you see acute inflammatory cells consider Giardiasis.

Treatment

  • Gluten free diet.
    • Mnemonic: BROW = barley, rye, oats, wheat.

DDx

  • Giardiasis.
    • Have giarrdia organisms.
    • Always consider Giardiasis and especially on exams.
  • Whipple's disease (very rare).
    • Abundant macrophages should make one suspicious.

Giardiasis

Etiology

  • Flagellate protozoan Giardia lamblia.

Histology

  • Loss of villi.
  • Intraepithelial lymphocytes.
    • +Other inflammatory cells, especially PMNs, close to the luminal surface.
  • Flagellate protozoa -- diagnostic feature.
    • Organisms often at site of bad inflammation.
    • Pale/translucent on H&E.
    • Size: 12-15 micrometers (long axis) x 6-10 micrometers (short axis) -- if seen completely.[4]
      • Often look like a crescent moon (image of crescent moon) or semicircular[5] -- as the long axis of the organism is rarely in the plane of the (histologic) section.

Notes:

  • Giardiasis can look (histologically) a lot like celiac disease.

Images:

Treatment

  • Antibiotics, e.g. metronidazole (Flagyl).

Whipple's disease

Epidemiology

  • Very rare.
  • Classically middle aged men.

Clinical

  • Malabsorption (diarrhea), arthritis + others.
    • Symptoms are non-specific.

Etiology

  • Infection - caused by Tropheryma whipplei.[6]

Histology

Features:[7]

  • Infectious microorganism typically found in macrophages.
    • Macrophages usually abundant - key feature that should raise Dx in DDx.
    • Organisms periodic acid-Schiff (PAS) positive.

Treatment

  • Antibiotics - for months and months.

Micrograph: Whipple's disease - wikipedia.org.

Tumours

Lymphoma

Main article: Lymphoma
  • Non-Hodgkin's lymphoma.
    • Enteropathy-associated T cell lymphoma (EATL) - due to celiac sprue.
    • MALT lymphoma.

Note:

Adenocarcinoma

  • Similar to large bowel adenocarcinomas (see colorectal tumours article).
  • Duodenum - most common site in small bowel.

Risk factors:

Neuroendocrine tumours

General

  • Like neuroendocrine tumours elsewhere.
  • Use of the term carcinoid is discouraged.[8][9][10]

Microscopic

Features:

  • Nests of cells.
  • Stippled chromatin - AKA: salt-and-pepper chromatin, coarse chromatin.
  • Classically subepithelial/mural.

Images:

Ampullary tumours

  • Ampullary carcinoma - has separate staging.
  • Intraductal papillary mucinous tumour (IPMT) - a pancreatic tumour, see pancreas article.

See also

References

  1. ↑ TN 2007 D22
  2. ↑ Kumar, V.; Jarzabek-Chorzelska, M.; Sulej, J.; Karnewska, K.; Farrell, T.; Jablonska, S. (Nov 2002). "Celiac disease and immunoglobulin a deficiency: how effective are the serological methods of diagnosis?". Clin Diagn Lab Immunol 9 (6): 1295-300. PMID 12414763.
  3. ↑ Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 843. ISBN 0-7216-0187-1.
  4. ↑ http://www.water-research.net/Giardia.htm
  5. ↑ http://en.wikipedia.org/wiki/Semicircle
  6. ↑ Liang Z, La Scola B, Raoult D (January 2002). "Monoclonal antibodies to immunodominant epitope of Tropheryma whipplei". Clin. Diagn. Lab. Immunol. 9 (1): 156?9. PMC 119894. PMID 11777846. http://cvi.asm.org/cgi/pmidlookup?view=long&pmid=11777846.
  7. ↑ Bai J, Mazure R, Vazquez H, Niveloni S, Smecuol E, Pedreira S, Mauriño E (2004). "Whipple's disease". Clin Gastroenterol Hepatol 2 (10): 849?60. doi:10.1016/S1542-3565(04)00387-8. PMID 15476147.
  8. ↑ Chetty, R. (Apr 2008). "Requiem for the term 'carcinoid tumour' in the gastrointestinal tract?". Can J Gastroenterol 22 (4): 357-8. PMID 18414708.
  9. ↑ Klöppel, G.; Perren, A.; Heitz, PU. (Apr 2004). "The gastroenteropancreatic neuroendocrine cell system and its tumors: the WHO classification.". Ann N Y Acad Sci 1014: 13-27. PMID 15153416.
  10. ↑ Klöppel G (July 2003). "[Neuroendocrine tumors of the gastrointestinal tract]" (in German). Pathologe 24 (4): 287–96. doi:10.1007/s00292-003-0636-7. PMID 14513276.
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