Marginal zone lymphoma

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) can involve the stomach, eye region, salivary glands, lung and other sites. Nodal MZL mainly affects lymph nodes. Splenic MZL often involves the spleen, marrow and blood. Pediatric and primary cutaneous marginal-zone entities require separate interpretation.

There is no single universal positive marker for MZL. Diagnosis integrates morphology, immune markers and the clinical pattern while excluding other small B-cell lymphomas. An IgM protein or a molecular result alone does not establish the subtype.

Tests are tailored to the site: tissue sampling, imaging, blood counts, LDH, viral screening and sometimes marrow assessment. Gastric disease needs endoscopic mapping and biopsies. PET is useful in selected settings, especially suspected transformation, but uptake varies and a negative scan cannot replace site-specific assessment.

Treatment is driven by symptoms, organ damage or compression, progressive lymphoma-related cytopenias and disease pace. Selected asymptomatic disease can be followed. Observation should specify review intervals, warning symptoms and the findings that would trigger treatment.

Testing for H. pylori and considering eradication treatment are central to gastric MALT care. Negative tests may need review because proton-pump inhibitors, recent antibiotics or sampling can affect detection. Some guidelines consider eradication even in apparently negative disease, but this is an individualized gastric pathway, not antibiotic treatment for all MZL.

Response can take time after eradication; stable microscopic residual disease does not always require immediate escalation. Endoscopic and histological follow-up is needed. Deep invasion, progression, persistent symptomatic disease or findings such as BIRC3::MALT1/t(11;18) can affect the chance of antibiotic response and the next step.

Localized non-gastric MALT can often be controlled with involved-site radiotherapy. Planning must consider the organ: eye dryness, salivary function and lung exposure are different concerns. Surgery is not automatically required simply because the lymphoma forms a localized mass.

Very-low-dose radiation can be useful for selected symptom relief or an adaptive approach, but FoRT showed that 4 Gy is less durable than 24 Gy for local control in indolent lymphoma. Discuss whether the goal is definitive control or palliation before comparing dose schedules.

In splenic MZL, anemia and other low blood counts may reflect marrow involvement, immune effects or an enlarged spleen. Rituximab can be an effective systemic option; splenectomy is reserved for selected circumstances rather than required for every diagnosis. Its infection and thrombosis implications need consideration.

Hepatitis C testing matters. In suitable HCV-associated indolent lymphoma without a need for immediate conventional lymphoma treatment, direct-acting antivirals may control the viral driver and induce lymphoma regression, as studied in BArT. Organ-threatening disease cannot simply wait for antiviral therapy alone.

Nodal MZL usually follows an indolent systemic-lymphoma approach, with observation, radiation for selected limited disease or antibody-based systemic treatment according to burden and symptoms. It should not inherit a gastric antibiotic strategy without the relevant diagnosis.

When disease is symptomatic or disseminated and needs treatment, anti-CD20 therapy alone or combined with an appropriate systemic regimen may be used. Prior remission duration, comorbidity and infection risk influence the choice and intensity. Repeated treatment should preserve immune and marrow reserve.

Zanubrutinib has a US indication for relapsed/refractory MZL after at least one anti-CD20-based regimen. MAGNOLIA demonstrated durable responses in a single-arm phase II study. Bleeding, infection, low counts, rhythm problems and interacting medicines still require review; “oral targeted therapy” does not mean risk-free treatment.

Lisocabtagene maraleucel is US-approved for adults with relapsed/refractory MZL after at least two prior systemic lines. The MZL cohort of TRANSCEND FL provides disease-specific evidence; its study name should not lead readers to think that only follicular lymphoma was assessed.

CAR-T assessment includes manufacturing time, bridging treatment, fitness, infection and caregiver logistics. CRS, neurological effects and prolonged immune suppression require an experienced service. It is not the routine starting treatment for newly diagnosed low-burden disease.

Recent studies of mosunetuzumab-based, response-adapted treatment include both FL and MZL. They expand research options but do not make the FL drug label a general MZL approval. Check the MZL sample size, trial phase and whether the proposed use is licensed or investigational.

New rapid enlargement, marked systemic symptoms or rising LDH warrants reassessment. Transformation to an aggressive lymphoma needs tissue confirmation when feasible and a different treatment pathway. A PET scan helps select a biopsy site but does not itself prove transformation.

Follow-up should remain site-specific. Gastric MALT may need continuing endoscopic surveillance even after a good lymphoma response; systemic disease follow-up focuses on symptoms, examination and relevant tests. Not every patient benefits from repeated routine PET scanning.

Bring the precise subtype, pathology material, organ-specific reports, infection tests and eradication results, all treatment dates and response assessments. For gastric disease, include endoscopy images and serial biopsy reports rather than only the latest scan.

Ask whether the disease needs treatment now, whether an infection is driving it, whether local treatment can meet the goal, and what would trigger a change. Before anti-CD20 treatment, review hepatitis B screening and the need for antiviral prevention.