[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Gastrointestinal tract](https://durgical.com/en/general-pathology/areas/gi/) › Gastrointestinal lymphoma

# Gastrointestinal lymphoma

- Lesion

The stomach is the commonest place outside the lymph nodes for lymphoma; many arise from lymphoid tissue induced by H. pylori.

Updated Nov 12, 2026

## Key points

- MALT lymphoma: dense lamina propria infiltrate of small B cells that invade glands, forming lymphoepithelial lesions.
- Markers: CD19 and CD20 positive, CD5 and CD10 negative; CD43 positive in a minority; light-chain restriction.
- Translocations: t(11;18) API2-MALT1 (commonest), t(14;18) MALT1-IGH, t(1;14) BCL10-IGH, t(3;14) FOXP1-IGH; the first three activate NF-κB.
- Tumours with t(11;18) or deep invasion usually do not respond to H. pylori eradication.
- Transformation to diffuse large B-cell lymphoma with p53 and p16 loss.
- Enteropathy-associated T-cell lymphoma: aggressive lymphoma of intraepithelial T cells in long-standing coeliac disease.

## What it is

Extranodal lymphomas arise most often in the gut, especially the stomach. The normal stomach has no organized lymphoid tissue; chronic H. pylori gastritis induces it, and an indolent extranodal marginal-zone B-cell lymphoma (MALT lymphoma, or MALToma) can emerge from it. Some MALT lymphomas regress after the bacterium is eradicated. Other gut lymphomas include diffuse large B-cell lymphoma, EBV-driven lymphoproliferations in transplant recipients and enteropathy-associated T-cell lymphoma in coeliac disease.

## Structure

- Endoscopy: thick folds, erosions or ulcers that look like gastritis.
- Small bowel lymphoma can form many small serosal nodules or diffusely thicken the wall.

## Step by step

- H. pylori infection induces lymphoid follicles in the gastric mucosa.
- Bacterial antigens stimulate T cells, which help polyclonal B cells to grow.
- A B-cell clone gains independence, often through a translocation activating NF-κB.
- The clone invades glands (lymphoepithelial lesions) and spreads in the mucosa.
- Further mutations may transform it into diffuse large B-cell lymphoma.

## Markers

- CD20+
- CD5−
- CD10−
- CD43±
- Kappa or lambda restriction

## Clinical notes

- Symptoms resemble gastritis: dyspepsia and epigastric pain, sometimes bleeding and weight loss.
- Iatrogenic immunosuppression (for example after transplantation) favours EBV-positive B-cell proliferations in the gut, where drug levels are highest.

## Memory aid

MALT is made by the microbe: remove the germ and the early tumour may melt, unless 11 meets 18.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the most common translocation in gastric MALT lymphoma?

t(11;18)(q21;q21), which creates an API2-MALT1 fusion that activates NF-κB.

## What is a lymphoepithelial lesion?

Neoplastic lymphocytes infiltrating and damaging gastric glands, characteristic of MALT lymphoma.

## Which lymphoma complicates long-standing coeliac disease?

Enteropathy-associated T-cell lymphoma, derived from intraepithelial T lymphocytes.

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## Elsewhere in DurgiPedia

- [Mucosa-associated lymphoid tissue (tonsils, Peyer patches)](https://durgical.com/en/immunology/mucosa-associated-lymphoid-tissue/)

## Connections

## Related 5

- [Helicobacter pylori gastritis](https://durgical.com/en/general-pathology/helicobacter-pylori-gastritis/)
- [Coeliac disease](https://durgical.com/en/general-pathology/coeliac-disease/)
- [Gastric adenocarcinoma: intestinal vs diffuse](https://durgical.com/en/general-pathology/gastric-adenocarcinoma-intestinal-vs-diffuse/)
- [Translocations, amplifications and epigenetic changes in cancer](https://durgical.com/en/general-pathology/translocations-amplifications-and-epigenetic-changes-in-cancer/)
- [Oncogenic viruses and H. pylori: the table to know](https://durgical.com/en/general-pathology/oncogenic-viruses-and-h-pylori-the-table-to-know/)

## Related conditions 3

- [Non-Hodgkin lymphoma](https://durgical.com/en/conditions/non-hodgkin-lymphoma/)
- [Helicobacter pylori gastritis](https://durgical.com/en/conditions/helicobacter-pylori-gastritis/)
- [Coeliac disease](https://durgical.com/en/conditions/coeliac-disease/)

## Microorganisms 1

- [Helicobacter pylori](https://durgical.com/en/microbiology/helicobacter-pylori/)

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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Helicobacter Pylori](https://www.ncbi.nlm.nih.gov/books/NBK534233/) (StatPearls (NCBI Bookshelf), 2025).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/general-pathology/gastrointestinal-lymphoma/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/gastrointestinal-lymphoma/