Marginal zone lymphomas are low grade lymphoma that are believed to arise from the lymphocytes of the marginal zone of lymphoid follicles. The marginal zone lies outside the mantle zone. It is most developed in the spleen. Marginal zone lymphomas comprises about 5–17% of all lymphomas.
Marginal Zone lymphomas are of three types:
- Splenic marginal zone B cell lymphoma: Marginal
- Extranodal marginal zone B cell lymphoma of mucosa associated lymphoid tissue (MALT) type
- Nodal marginal zone B cell lymphoma
The three types of marginal zone lymphoma are distinct in terms of etiology clinical presentation and treatment but share several common features. These include
- They have a similar phenotype
- Positive for CD19, CD20, and CD22,
- Negative for cyclin D1, CD5, CD10, and usually CD23
- Relation to infection and inflammations:
- Helicobacter pylori is implicates in gastric MALT,
- Chlamydophila psittaci in lymphoma of the ocular adnexa,
- Borrelia burgdorferi in cutaneous marginal zone lymphoma in Europe but not in the US and Asia.
- Campylobacter jejune in alpha heavy chain disease that is a form of the small intestine MALT lymphomas,
- Mycobacterium spp. For the MALT of the bronchus,
- Hepatitis C virus (HCV) for splenic and nodal MZL.
- Hashimoto thyroiditis
- Sjogeren’s syndrome Sjogren Syndrome (SS) display a 1000-fold increased risk of developing a MALT lymphoma
- Response to antibioitics
- Gastric MALT responds to anti H. pylori treatment
- Occular marginal zone lymphomas respons to doxycycline therapy in patients in whom C psittaci is detected in the biopsy specimen.