# Gastrointestinal Lymphoma and MALT Lymphoma > Gastrointestinal lymphoma and MALT lymphoma for NEET-PG Medicine, with H. pylori-driven lymphoma, t(11;18), regression after eradication and IPSID. - Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/gastrointestinal-lymphoma-and-malt-lymphoma - Exam / course: NEET-PG · Subject: Medicine - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-14 - Last updated: 2026-10-14 - Reference basis: Harrison's Principles of Internal Medicine; Sleisenger and Fordtran's Gastrointestinal and Liver Disease; Robbins and Cotran Pathologic Basis of Disease - How to cite: "Gastrointestinal Lymphoma and MALT Lymphoma", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/gastrointestinal-lymphoma-and-malt-lymphoma ## Direct answer Gastrointestinal lymphoma is a lymphoma arising in the bowel, and most are B-cell non-Hodgkin lymphomas, with the stomach as the commonest site. MALT lymphoma is a low-grade marginal zone B-cell lymphoma driven by chronic Helicobacter pylori infection in most gastric cases. Early gastric MALT lymphoma often regresses after H. pylori eradication, which is therefore the first-line treatment. ## What you must remember - **Commonest site:** the stomach is the most frequent site of primary gastrointestinal lymphoma, and gastric MALT lymphoma is a major subtype. - **H. pylori link:** persistent gastritis drives B-cell proliferation through chronic antigenic stimulation by T cells, so eradication removes the trigger. - **Regression:** early (stage IE) gastric MALT lymphoma often disappears after eradication, although the response can take several months. - **t(11;18)(q21;q21):** the API2-MALT1 fusion predicts poor response to antibiotic therapy and needs closer follow-up. - **Other translocations:** t(14;18) (IGH-MALT1) and t(1;14) (BCL10) define other subsets of MALT lymphoma. - **Lymphoepithelial lesions:** the histological hallmark, where neoplastic B cells infiltrate and damage the glandular epithelium. - **IPSID:** immunoproliferative small intestinal disease, a small-bowel variant of alpha heavy chain disease linked with Campylobacter jejuni, often responsive to antibiotics when early. - **Transformation:** MALT lymphoma can transform into diffuse large B-cell lymphoma, which needs chemoimmunotherapy. ## A fixed sequence from biopsy to remission A gastric lymphoma found on endoscopic biopsy is managed in a fixed sequence, and the H. pylori status decides the first treatment. Histology and staging are settled before any drug is started, because limited and advanced disease are treated differently. 1. **Confirm the histology.** Immunohistochemistry on the biopsy shows a marginal zone B-cell infiltrate with lymphoepithelial lesions. 2. **Test for H. pylori.** Biopsy-based histology or a breath test identifies the infection that is driving the lymphoma. 3. **Stage the disease.** Computed tomography of the chest, abdomen and pelvis, with endoscopic ultrasound for depth, is staged by the Lugano-modified Ann Arbor system. 4. **Give eradication therapy.** A combined antibiotic regimen is chosen against local resistance patterns, because clarithromycin resistance has made single regimens unreliable. 5. **Reassess after several months.** Endoscopy and biopsy confirm remission, and persisting disease moves to the next step. 6. **Treat refractory or advanced disease.** Rituximab, chemotherapy or involved-site radiotherapy is selected by stage and by the presence of a t(11;18) translocation. ## Where the exam tries to catch you Examiners test whether you know when antibiotics are enough and when they are not. - **Trap:** starting chemotherapy for every gastric MALT lymphoma — **Correct:** early H. pylori-positive disease is treated first with eradication, and chemotherapy is kept for failure or advanced stage. - **Trap:** expecting regression in every case — **Correct:** t(11;18) disease responds less reliably to eradication, so it needs closer follow-up and early escalation. - **Trap:** equating IPSID with ordinary gastric lymphoma — **Correct:** IPSID is the small-bowel form of alpha heavy chain disease, linked to Campylobacter jejuni, and responds to antibiotics when early. ## Frequently asked questions ### Which translocation predicts poor response to antibiotic treatment in gastric MALT lymphoma? The t(11;18)(q21;q21) translocation, which creates the API2-MALT1 fusion, predicts a poor response to H. pylori eradication in gastric MALT lymphoma. Patients with this translocation often need further treatment, such as chemotherapy or radiotherapy, when disease persists after eradication. ### What is the first-line treatment for early gastric MALT lymphoma? Early H. pylori-positive gastric MALT lymphoma is first treated with H. pylori eradication, which often induces regression over several months. Disease that persists or progresses after eradication is then managed with rituximab, chemotherapy or radiotherapy, depending on stage. ### What is IPSID and how is it treated? Immunoproliferative small intestinal disease, IPSID, is the small-bowel variant of alpha heavy chain disease, and it is linked with Campylobacter jejuni infection. Early IPSID is often treated with antibiotics such as tetracycline, while advanced disease needs chemotherapy. ### Can MALT lymphoma transform into a more aggressive lymphoma? Yes, MALT lymphoma can transform into diffuse large B-cell lymphoma, usually recognised by rapid enlargement, a new mass or systemic symptoms. Transformed disease needs chemoimmunotherapy, so follow-up is needed even after apparent remission of the MALT lymphoma. ### What is the histological hallmark of gastric MALT lymphoma? Lymphoepithelial lesions are the histological hallmark of gastric MALT lymphoma, where neoplastic B cells infiltrate and damage the glandular epithelium. Their presence on biopsy, together with a marginal zone B-cell phenotype on immunohistochemistry, supports the diagnosis.