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Table of Contents
Definition / general | Clinical features | Case reports | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Molecular / cytogenetics descriptionCite this page: Gulwani H. MALT lymphoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mediastinumMALT.html. Accessed March 23rd, 2019.
Definition / general
- Very rare in thymus, < 20 cases reported
Clinical features
- May arise without underlying autoimmunity (Lung 2011;189:461); these cases often involve males or older patients (Leuk Lymphoma 2011;52:2276)
Case reports
- 36 year old woman with Sjögren syndrome and coexisting thymic and gastric MALT (Arch Pathol Lab Med 2000;124:770)
- 63 year old woman with possible connective tissue disease (Hum Pathol 2000;31:255)
- Patient with Sjögren syndrome and cryoglobulinemia (Pathology 2009;41:701)
Gross description
- Centered in thymus
Microscopic (histologic) description
- Clusters of centrocyte-like lymphoid cells in lymphoepithelial lesions mixed with mature lymphocytes and lymphoid follicles with reactive germinal centers
- Also plasma cells
- Variable microcysts
- Early MALT cases in patients with thymic lymphofollicular hyperplasia and myasthenia gravis or connective tissue disease have ill defined lymphoid follicles with sheets of centrocyte-like B cells disrupting the medullary epithelial cytokeratin network
Microscopic (histologic) images
Images hosted on other servers:
Thymic tumor
Electron microscopy description
- Nuclei with irregular protrusions or blebs
- No intercellular junctions, no cytoplasmic filament bundles, neurosecretory granules, synaptic vesicles, microtubules, basal lamina, cytoplasmic processes or primitive sarcomeres
Molecular / cytogenetics description
- Trisomy 3 may play a role in lymphoma development (Pathol Int 2012;62:93)
- Thymic MALT lymphomas have a characteristic pattern of chromosomal aberrations that may be similar to those of other autoimmune associated MALT lymphomas
- Monoclonal IgH rearrangement present (Am J Clin Pathol 2002;117:51)
