Difference between revisions of "Stomach"

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Stomach is an important organ for pathologists. It is often inflammed and may be a site that cancer arises from. Gastroenterologists often biopsy the organ. Surgeon take-out the organ.

Gross anatomy

  • Cardia - first part of the stomach; joins with esophagus.
  • Fundus - superior portion - not attached directly to the esophagus.
  • Body - contains parietal cells.
  • Pylorus - distal (think pyloric stenosis).

Image: Stomach anatomy (wikipedia.org).

Microscopic

Foveolar cells vs. intestinal goblet cells

  • Intestinal goblet cells - clear mucin.
  • Foveolar cells - eosinophilic contents.

Stomach vs. intestine

  • Villin (+ve in small intestine).
  • PAS-D (+ve in foveolar epithelium).

Stomach vs. intestine[1]

Intestine Stomach
Spacing Goblets cell - spaced Folveolar cells - beside one another
Morphology of epithelial cells columnar tall columnar (Champagne flute)
Vesicle at luminal surface touching/small opening wide open
PAS-D +ve (???) -ve (???)
Villin stain +ve (???) -ve (???)
Images Tubular adenoma - goblet cells on right of image (WC) Gastric biopsy (microscopy-uk.org.uk)

Notes:

  • Intraepithelial lymphocytes in the gastric mucosa have a clear halo around 'em.[2]
  • Memory device: Folveolar cells have friends, i.e. they are close to other folveolar cells.

Ref.

  • PMID 11984877.

Useful stains for stomach

  • Cresyl violet stain[3] - used to find H. pylori.[4]
  • Alcian blue - used to find mucin[5] which is present in intestinal metaplasia
    • Other mucins stains:[6] mucicarmine, PAS, PASD (doesn't stain glycogen)

Things to look for...

  • Parietal cells (indicate you're in the body of the stomach) - pink (eosinophilic) cytoplasm.
    • Lack of parietal cells -- DDx: Bx of antrum (pylorus), Bx of cardia, pernicious anemia.
  • Goblet cells = intestinal metaplasia.
  • Architectural distortion of gastric glands - suspect cancer.
  • Signet ring cells = (usually) gastric carcinoma.
    • Can be very easy to miss in some biopsies.
  • Inflammation + small bacteria = suspect H. pylori gastritis.

Gastritis

Etiology

A specific cause is uncommonly identified histologically.

Gastritis causes:[7]

  • Infectious:
    • H. pylori infection.
    • Tuberculosis.
    • Salmonellosis.
    • CMV.
  • Endocrine-related:
    • Pernicious anemia.
    • Diabetes - gastric atony.
  • Trauma, e.g. NG tube.
  • Vascular, ischemia.
  • Autoimmune:
    • Crohn's disease.
  • Toxins:
    • Alcohol.
    • Medications (NSAIDS).
    • Medications.
    • Uremia.
    • Smoking (heavy).
  • Radiation.

Endoscopic appearance

  • Erythematous.

Microscopic

  • Inflammatory cells - in particular.
    • Neutrophils (active gastritis) - especially when intraepithelial, or
    • Plasma cells (in lamina propria).
      • Various criteria:
        1. Two plasma cells kissing, i.e. two plasma cells touching/overlapping.
        2. Three is a crowd, i.e. three plasma cells in close proximity.

Sydney criteria for gastritis

A bunch of pathologists in Sydney came-up with criteria... and these were revised in Houston.[8]

Classification[8]

Non-atrophic Helicobacter Atrophic Helicobacter Autoimmune
Inflammation pattern antral or diffuse antrum & corpus, mild inflammation corpus only
Atrophy & metaplasia nil atrophy present, metaplasia at incisura corpus only

Notes:

  • Corpus = gastric body.
  • Incisura = angular incisure, incisura angularis (Latin) - notched transition point on lesser curvature of the stomach between pylorus and body.[9]

Severity

The Sydney group suggests grading severity with the following language:[8]

  • Mild.
  • Moderate.
  • Marked.

These terms are applied to the parameters described in a biopsy. The Sydney criteria lists H. pylori, neutrophils, mononuclear cells, antrum (atrophy), corpus (atrophy) and intestinal metaplasia. The paper that discusses this also give a visual analogue scale.

Parameters & Severity (adapted from Dixon et al.[8]):

Mild Moderate Marked
H. pylori few touching many touching piles
Neutrophils few bunches crowded
Mononuclear cells not touching kissing partying

Helicobacter spp gastritis

  • Several Helicobacter species can cause gastritis; H. pylori most common

Finding Helicobacter

  • Small - smaller than the nucleus of the gastric foveolar cell.
    • On 400x they are still possible to miss.
  • Commonly have a "v" shape.
  • Look close to the opening of the gastric glands.
  • Are often are found in groups.
  • Location - can be antrum and/or body.[10]
  • Helicobacter don't like the intestinal mucosa or mucosa that has undergone intestinal metaplasia -- you're unlikely to find 'em there.

Image: H pylori IHC - wikipedia.org.

Epidemiologic associations

Helicobacter infections are associated with:[11]

  • Gastritis.
  • Peptic ulcers.
  • Cancer.
    • Carcinoma.
    • MALT lymphoma.

Intestinal metaplasia

Microscopy

  • Goblet cells are present in the stomach.[12]
    • With cresyl violet vacuole stains blue.
    • With H&E vacuole may stain greyish.

Significance

  • Thought to be signifant risk to carcinoma.[13]
  • May be associated with Helicobacter spp. infection, though Helicobacter don't like intestinal type mucosa, i.e. H. pylori are not typically found in regions with intestinal metaplasia.

Gastric dysplasia

General

  • Criteria similar to those in adenomatous colonic polyps - see Microscopic.
  • Divided into:
    • Low grade.
    • High grade.
      • Nuclei no longer stratified.

Microscopic

  • Nuclear changes.
    • Nuclear crowding/pseudostratification.
    • Elongation of nuclei (cigar-shaped nuclei).
  • Cytoplasm - hyperchromatic.
  • Mitosis - particularily above the basement membrane.

Image: Gastric adenoma (wikipedia.org).

Gastric polyps

Similar to colonic polyps - see intestinal polyps.

DDx polyp (similar to colon & rectum):

  • Hyperplastic - most common, characterised by abundant elongated foveola + glands.
  • Hamartomatous - weriod stuff.
  • Inflammatory fibroid polyp - inflammation, myxoid stroma.
  • Fundic gland polyp - cystic dilation, flat epithelium.
  • Adenomatous polyp.

Hyperplastic polyp

Histology

Features:[14]

  • Abundant foveolar cells and elongated glands

Negatives:

  • No atypical nuclei.
  • No hyperchromasia.
  • No loss of pseudostratification.

Links

Adenomatous polyps

Divided into 'gastric' and 'intestinal type'[15]

Histology

  • Type.
    • Intestinal: goblet cells or Paneth cells.
    • Gastric: foveolar epithelium. (???)
  • Architectural crowding of glands.
  • Hyperchromasia of cytoplasm.
  • Nuclear changes:
    • Loss of nuclear polarity.
    • Incr. NC ratio.
    • Elongation of nucleus.

Fundic gland polyps

General

  • Fundic location - duh!

Micro

Features:[16]

  • Polypoid shape (may not be appreciated on microscopy).
  • Dilated gastric glands.
    • Flatted epithelial lining - key feature.

Significance

  • Weak association with FAP (Familial Adenomatous Polyposis).[17]
  • Associated with chronic proton pump inhibitors (PPI) use -- approximately 4x risk.[18]

Note:

Gastric antral vascular ectasia

General

  • Abbreviated GAVE.
  • Antrum lesion - due dilated capillaries.
  • AKA watermelon stomach - due to characteristic endoscopic appearance.[20]

Gross/endoscopic appearance

  • Linear red streaks in antrum - oriented toward the pyloric valve... vaguely resembles a watermelon.

Endoscopic images:

Microscopic[21]

  • Fibrin thrombi - characteristic feature.
  • Dilated capillaries in lamina propria.

Reactive gastropathy

General

  • May be seen in the context of a previous resection/surgical reconstruction, e.g. Billroth II.

Epidemiology

  • Associated with...[22]
    • Excess acid.
    • EtOH.
    • Bile.
    • H. pylori.


Gastric cancer

Gastric lymphoma

  • MALT lymphoma = mucosa-associated lymphoid tissue lymphoma.
  • Associated with helicobacter infection.[23]

Micrography

  • "Lymphoepithelial lesion" - gastric crypts invaded by a monomorphous population of lymphocytes.

IHC - work-up

  • Panker -- most useful.

Others:

  • CD3, CD20, CD138, kappa, lambda, Bcl-2.

Treatment

  • Triple therapy (two antibiotics, proton pump inhibitor (PPI)).[24]
  • Surgery - if triple therapy fails.

Gastric adenocarcinoma

General

  • Two different classification schemes.
    • Lauren[25] - two types:
      • Intestinal type (mass forming).
      • Diffuse type (infiltrative).
    • WHO classification - 6 subtypes for adenocarcinoma (papillary, tubular, mucinous, signet-rign, undifferentiated, adenosquamous).[26]

Epidemiology

  • Associated with helicobacter infections.
  • Prognosis is often poor as it is discovered at a late stage.
  • Higher prevalence in countries in the far east (e.g. Japan) - thought to be environmental, e.g. diet.

Microscopy

  • Adenocarcinoma - gland-forming lesion.
  • Signet ring carcinoma.

Treatment

  • Surgical excision.
    • Proximal tumours may require a complete gastrectomy as the stomach is innervated from its proximal part.

See also

References

  1. ↑ ALS. 4 Feb 2009.
  2. ↑ Sternberg H4P 2nd Ed., P.484
  3. ↑ http://www.histology-world.com/stains/stains.htm
  4. ↑ Goggin N, Rowland M, Imrie C, Walsh D, Clyne M, Drumm B (December 1998). "Effect of Helicobacter pylori eradication on the natural history of duodenal ulcer disease". Arch. Dis. Child. 79 (6): 502-5. PMC 1717771. PMID 10210995. http://adc.bmj.com/cgi/pmidlookup?view=long&pmid=10210995.
  5. ↑ http://www.histology-world.com/stains/stains.htm
  6. ↑ http://www.histology-world.com/stains/stains.htm
  7. ↑ PBoD PP.812-3.
  8. ↑ 8.0 8.1 8.2 8.3 Dixon MF, Genta RM, Yardley JH, Correa P (October 1996). "Classification and grading of gastritis. The updated Sydney System. International Workshop on the Histopathology of Gastritis, Houston 1994". Am. J. Surg. Pathol. 20 (10): 1161-81. PMID 8827022. http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0147-5185&volume=20&issue=10&spage=1161.
  9. ↑ http://en.wikipedia.org/wiki/Angular_incisure
  10. ↑ Maaroos HI, Kekki M, Villako K, Sipponen P, Tamm A, Sadeniemi L (October 1990). "The occurrence and extent of Helicobacter pylori colonization and antral and body gastritis profiles in an Estonian population sample". Scand. J. Gastroenterol. 25 (10): 1010-7. PMID 2263873.
  11. ↑ PBoD P.814.
  12. ↑ http://esynopsis.uchc.edu/eAtlas/GI/1280.htm
  13. ↑ need one
  14. ↑ http://pathologyoutlines.com/stomach.html#hyperplastic
  15. ↑ NEED ONE
  16. ↑ NEED REF.
  17. ↑ Freeman HJ (March 2008). "Proton pump inhibitors and an emerging epidemic of gastric fundic gland polyposis". World J. Gastroenterol. 14 (9): 1318-20. PMID 18322941. http://www.wjgnet.com/1007-9327/14/1318.asp.
  18. ↑ Jalving M, Koornstra JJ, Wesseling J, Boezen HM, DE Jong S, Kleibeuker JH (November 2006). "Increased risk of fundic gland polyps during long-term proton pump inhibitor therapy". Aliment. Pharmacol. Ther. 24 (9): 1341-8. doi:10.1111/j.1365-2036.2006.03127.x. PMID 17059515.
  19. ↑ Masaoka T, Suzuki H, Hibi T (May 2008). "Gastric epithelial cell modality and proton pump inhibitor". J Clin Biochem Nutr 42 (3): 191-6. doi:10.3164/jcbn.2008028. PMC 2386521. PMID 18545640. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2386521/.
  20. ↑ Chatterjee S (July 2008). "Watermelon stomach". CMAJ 179 (2): 162. doi:10.1503/cmaj.080461. PMC 2443230. PMID 18625989. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=18625989.
  21. ↑ GILP P.118
  22. ↑ ALS 5 Feb 2009.
  23. ↑ Mbulaiteye, SM.; Hisada, M.; El-Omar, EM. (2009). "Helicobacter Pylori associated global gastric cancer burden.". Front Biosci 14: 1490-504. PMID 19273142.
  24. ↑ Zullo, A.; Hassan, C.; Andriani, A.; Cristofari, F.; De Francesco, V.; Ierardi, E.; Tomao, S.; Morini, S. et al. (Aug 2009). "Eradication therapy for Helicobacter pylori in patients with gastric MALT lymphoma: a pooled data analysis.". Am J Gastroenterol 104 (8): 1932-7; quiz 1938. doi:10.1038/ajg.2009.314. PMID 19532131.
  25. ↑ PMID 14320675.
  26. ↑ PBoD P.823.
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