Mucosa-associated lymphoid tissue (MALT) lymphoma is categorised as indolent or low-grade B-cell lymphoma; however, high-grade histological transformation can occur.
Median age at presentation is 61 years.
The stomach is the most frequently involved organ, and in most cases (90%), there is a strong association between gastric MALT lymphoma and chronic Helicobacter pylori infection.
Other sites that may be involved include the salivary glands, eyes, lung, intestinal tract, skin, and thyroid gland. May also occur (rarely) in breasts, dura, and genitourinary tract. Autoimmune diseases have been linked to non-gastric MALT lymphoma.
Diagnosis is based on history, physical examination, radiological imaging studies, histopathological and immunohistochemical evaluation of the biopsy specimen, and molecular laboratory techniques.
Treatment is based on the histological subtype and severity of symptoms at presentation. Surgery, radiotherapy, and chemotherapy all play a role. H pylori-eradication therapy is the mainstay of treatment for localised H pylori-positive gastric MALT lymphoma.
The World Health Organization (WHO) has defined mucosa-associated lymphoid tissue (MALT) lymphoma as "an extranodal lymphoma composed of morphologically heterogenous small B cells, including marginal zone cells, cells resembling monocytoid cells, small lymphocytes, and scattered immunoblasts and centroblast-like cells". Plasma cell differentiation occurs in a proportion of cases. The infiltrate is located in the marginal zone of reactive B-cell follicles and extends into the interfollicular region. Lymphoepithelial lesions develop in epithelial tissues due to infiltration of the epithelium with neoplastic cells. The stomach is the most commonly involved organ and there is an important association with chronic Helicobacter pylori infection in the majority of gastric MALT lymphoma cases. MALT lymphomas are categorised as indolent or low-grade B-cell lymphomas. Very rarely do they show features of high-grade histology or transformation at the time of initial presentation.
History and exam
Key diagnostic factors
- history of Helicobacter pylori gastritis
- history of autoimmune disorder
- age >60 years
- epigastric discomfort
- skin lesions
- red eye ± photophobia
- painless proptosis, diplopia, motility disturbances of the eye, ptosis, decreased vision
Other diagnostic factors
- nausea and/or vomiting
- GI bleeding
- night sweats
- weight loss
- shortness of breath, haemoptysis, cough
- salivary gland swelling
- thyroid swelling
- breast lump
- focal neurological deficits
- Helicobacter pylori infection
- age >60 years
- autoimmune diseases
- female sex
- Chlamydia psittaci infection
- Campylobacter jejuni infection
- Borrelia burgdorferi infection
- hepatitis C virus infection
- HIV infection
1st investigations to order
- blood smear
- upper GI endoscopy
- biopsy of affected tissue
- staging CT scan
- H pylori serology
- H pylori stool antigen test
- basic metabolic profile
Investigations to consider
- bone marrow biopsy
- reverse transcriptase polymerase chain reaction (RT-PCR) or fluorescence in situ hybridisation (FISH)
- immunoglobulin gene rearrangement studies
- serum electrophoresis
- serum LDH
- serum beta-2 microglobulin
- 18F-fluorodeoxyglucose (FDG) PET/CT scan
- endoscopic ultrasound of the stomach
- double contrast radiography of the GI tract
- lower GI endoscopy
- endoscopic otolaryngology
- CT scan of salivary glands
- MRI orbit
- hepatitis C serology
- hepatitis B serology
- HIV serology
- multiple-gated acquisition scan (MUGA)
- ethylenediamine tetra-acetic acid glomerular filtration rate (EDTA GFR)
low-grade localised gastric: Helicobacter pylori-positive
low-grade localised gastric: Helicobacter pylori-negative
low-grade advanced gastric
high-grade histological transformation: gastric or non-gastric
Christopher McNamara, MBBS (Hons), FRACP, FRCPA, FRCPath
Royal Free Hospital
CM declares that he has no competing interests.
Dr Christopher McNamara wishes to gratefully acknowledge Dr Rahul Joshi, a previous contributor to this topic. RJ declared that he had no competing interests. Unfortunately, we have since been made aware that Dr Rahul Joshi is deceased.
Markus Raderer, MD
Professor of Medicine
Department of Internal Medicine I
Division of Oncology
Medical University Vienna
MR is an author of a number of references cited in this topic.
Alan Lichtin, MD
Cleveland Clinic Taussig Cancer Center
AL declares that he has no competing interests.
Ian Chau, MD
Consultant Medical Oncologist
Royal Marsden Hospital
IC has been reimbursed by Roche Products, the manufacturer of rituximab, for attending several conferences. IC has also served on advisory boards and received honorarium for giving presentations for Roche Products. IC has received research funding from Novartis to conduct academic studies in the treatment of colorectal cancer.
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