MALT Lymphoma

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This blog is for informational purposes only and should not be taken as medical advice. Content is sourced from third parties, and we do not guarantee accuracy or accept any liability for its use. Always consult a qualified healthcare professional for medical guidance.

What is MALT Lymphoma?

Mucosa-Associated Lymphoid Tissue (MALT) lymphoma is a rare, indolent type of marginal zone B-cell non-Hodgkin lymphoma that originates in lymphoid tissue associated with mucous membranes, such as the stomach, salivary glands, lungs, thyroid, or eyes. It accounts for about 8% of all non-Hodgkin lymphomas and is often linked to chronic inflammation or autoimmune conditions. MALT lymphoma is typically low-grade, localized, and slow-growing, but it can transform into more aggressive forms like diffuse large B-cell lymphoma in 10-20% of cases. In 2025, approximately 5,000-6,000 new cases are diagnosed annually in the US, with a median age at diagnosis of 60-65 years, affecting women slightly more than men.

Symptoms

Symptoms of MALT lymphoma vary depending on the affected site but are often subtle and related to chronic inflammation. In gastric MALT (the most common, 50-70% of cases), symptoms include abdominal pain, indigestion, nausea, vomiting, weight loss, and bloating, mimicking peptic ulcers or gastritis. For ocular MALT, patients experience red eyes, blurred vision, or floaters. Salivary gland involvement causes swelling (parotid or submandibular glands), dry mouth, or facial asymmetry. Pulmonary MALT may present with chronic cough, shortness of breath, or chest pain. General symptoms like fatigue, night sweats, and low-grade fever occur in advanced or disseminated disease. Symptoms can persist for months to years before diagnosis.

Causes

MALT lymphoma is strongly associated with chronic antigenic stimulation from infections or autoimmune diseases, leading to lymphoid tissue proliferation and eventual malignant transformation. Helicobacter pylori infection causes 90% of gastric MALT lymphomas, with antibiotic eradication often curing early cases. Other associations include Chlamydia psittaci (ocular), Borrelia burgdorferi (skin), Campylobacter jejuni (small intestine), and autoimmune conditions like Sjögren’s syndrome (salivary glands) or Hashimoto’s thyroiditis (thyroid). Genetic mutations, such as t(11;18) translocation involving API2-MALT1 in 25-50% of gastric cases, confer resistance to antibiotics. Risk factors include older age, female gender, and immunosuppression. In 2025, research emphasizes how microbial dysbiosis and immune dysregulation drive oncogenesis.

Diagnosis

Diagnosis begins with clinical evaluation and imaging tailored to the site: endoscopy with biopsy for gastric MALT, CT/MRI for salivary or pulmonary involvement, and ophthalmologic exam for ocular. Biopsy is essential, showing small B-cells with immunohistochemistry (CD20+, CD5-, CD10-, BCL2+). Molecular testing detects translocations (e.g., t(11;18) by FISH) and immunoglobulin gene rearrangements for clonality. Staging uses Lugano criteria, including bone marrow biopsy and PET-CT to assess dissemination (10-20% extragastric spread). H. pylori testing (urea breath test, stool antigen) is routine for gastric cases. In 2025, next-generation sequencing identifies predictive mutations, improving diagnostic precision.

Treatment

Treatment depends on site, stage, and H. pylori status. For early gastric MALT (stage IE-IIE1), H. pylori eradication with antibiotics (clarithromycin, amoxicillin, proton pump inhibitor) achieves 75-80% remission. Persistent or non-gastric cases use rituximab monotherapy or combined with chemotherapy (R-CVP or R-bendamustine). Radiation therapy (involved-site, 24-30 Gy) cures 90% of localized disease with low toxicity. Advanced or transformed cases require aggressive regimens like R-CHOP, followed by maintenance rituximab. Watchful waiting is an option for asymptomatic, indolent cases. In 2025, novel agents like BTK inhibitors (ibrutinib) show 50% response in relapsed MALT, and immunotherapy trials explore PD-1 inhibitors.

Future Outlook

In 2025, MALT lymphoma has an excellent prognosis, with 5-year survival exceeding 90% for localized disease and 70-80% overall, thanks to infection-targeted therapies. Antibiotic resistance in H. pylori strains poses challenges, but molecular-guided treatments improve outcomes in 20-30% of resistant cases. Research focuses on microbiome modulation, vaccine development against associated pathogens, and precision therapies for translocations. By 2030, these could achieve near-100% cure rates for early-stage and 90% for advanced, with reduced reliance on chemotherapy through targeted agents.

Sources

Cleveland Clinic’s “Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma” for symptoms and treatment; Mayo Clinic’s “Marginal zone lymphoma – Symptoms and causes” for causes; PMC’s “Mucosa-associated lymphoid tissue (MALT) lymphoma” for overview; Lymphoma Action’s “Marginal zone lymphomas” for staging; NCI’s “B-Cell Non-Hodgkin Lymphoma Treatment” for therapies; Blood Cancer UK’s “Marginal zone lymphoma” for prognosis; Leukemia & Lymphoma Society’s “Marginal Zone Lymphoma” for details; Cancer Research UK’s “Marginal zone lymphoma” for research; Lymphoma Research Foundation’s “Marginal Zone Lymphoma” for subtypes; OncoDaily’s “MALT Lymphoma: Symptoms, Diagnosis, Treatment, and 2025 Advances” for updates.