collagenous gastritis

Definition: Colagenous gastritis is characterized by a thick band of collagen immediately beneath the surface epithelium of the gastric mucosa.

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In collagenous gastroduodenitis associated with collagenous colitis, the collagen band in the gastric mucosa can be at the level of the foveolar isthmus.

Only rare cases of this entity have been described, and its clinical associations remain unclear.

Collagenous gastritis is rare, affecting men and women, children and adults.

The disease occurs as an isolated disorder or it may coexist with collagenous colitis and/or collagenous duodenitis, lymphocytic colitis, Sjögren syndrome, and ulcerative colitis.

Patients range in age from 11 to 77 with a mean age of 40.

It appears that there are two subsets of patients with collagenous gastritis:
 (a) collagenous gastritis occurring in children and young adults who present with severe anemia, a nodular endoscopic pattern, and disease limited to the gastric mucosa;
 (b) collagenous gastritis associated with collagenous colitis in adults with chronic watery diarrhea.

Some patients present with vomiting or upper GI bleeding, whereas others are asymptomatic or have non-specific symptoms.

Rare patients improve on gluten-free diets.

Other patients have slowly progressive disease.

The cause of collagenous gastritis is unknown, but it may result from immune-mediated processes.

In the stomach, signs of local immuneactivation include epithelial overexpression of HLA-DR+ and increased numbers of CD3+
intra-epithelial lymphocytes and CD25+ cells in the lamina propria.

Endoscopic abnormalities include erythema, mucosal hemorrhage, and mucosal nodularity involving the corpus and body and sparing the antrum.

The stomach shows histologic changes resembling those present in collagenous sprue (in the small bowel) or collagenous colitis. The diagnosticcriteria consist of a subepithelial collagen layer >10 μm in thickness, lamina propria lymphoplasmacytosis, intraepithelial lymphocytes, and epithelial damage.

The distribution and thickness of the subepithelial collagen bands varies within and between biopsy specimens and can be highlighted by trichrome stains.

Its thickness ranges from 13 to 96 μm,averaging close to 40 μm.

It is discontinuous and irregular and contains entrapped dilated capillaries and mononuclear cells. Intraepithelial CD3+ T lymphocytes range from 14 to >30 per 100 surface epithelial cells with a mean of 20.

A patchy chronic active gastritis may be present.

The lamina propria contains variable numbers of neutrophils, eosinophils, and mast cells.

Patchy epithelial damage with surface cell flattening, reactive epithelial changes, and focal sloughing are present.

Rare abscesses form.

The regenerative surface epithelial changes may be severe enough to warrant a diagnosis of indeterminate for dysplasia.

The stomach may also show patchy glandular atrophy with shortening ofthe oxyntic glands.

However, parietal and chief cells are still present.

There may also be linear or micronodular endocrine cell hyperplasia in the corpus, a change thatmay result from treatment with proton pump inhibitors (PPI).

In addition, intestinal metaplasia may develop in long standing disease.

Smooth muscle hyperplasia deep in the lamina propria increases over time with extension to the surface.

References

 Collagenous gastritis: histopathologic features and association with other gastrointestinal diseases. Leung ST, Chandan VS, Murray JA, Wu TT. Am J Surg Pathol. 2009 May;33(5):788-98. PMID: 19295410

 Collagenous Gastritis: Histopathologic Features and Association With Other Gastrointestinal Diseases. Leung ST, Chandan VS, Murray JA, Wu TT. Am J Surg Pathol. 2009 Mar 17. PMID: 19295410

 Kori M, Cohen S, Levine A, Givony S, Sokolovskaia-Ziv N, Melzer E, Granot E. Collagenous gastritis: a rare cause of abdominal pain and iron-deficiency anemia. J Pediatr Gastroenterol Nutr. 2007 Nov;45(5):603-6. PMID: 18030241

 Vesoulis Z, Lozanski G, Ravichandran P, Esber E. Collagenous gastritis: a case report, morphologic evaluation, and review. Mod Pathol. 2000 May;13(5):591-6. Review. PMID: 10824933

 Cote JF, Hankard GF, Faure C, Mougenot JF, Holvoet L, Cezard JP, Navarro J, Peuchmaur M. Collagenous gastritis revealed by severe anemia in a child. Hum Pathol. 1998 Aug;29(8):883-6.PMID: 9712433