Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma)
Colon and rectum
Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) comprises up to 8% of B-cell lymphomas and manifests predominantly in the stomach, less frequently in lung, skin, and ocular adnexa. It arises from the marginal zone of lymphoid tissues and is histologically characterized by small to medium sized morphologicall heterogeneous atypical lymphocytes. In many cases of MALT lymphoma, there is a history of a chronic inflammatory disorder that results in accumulation of extra nodal lymphoid tissue. Risk factors include infectious organisms, e.g. H. pylori (gastric MALT lymphoma), Chlamydia psittaci (ocular adnexal MALT lymphoma) Campylobacter jejuni (IPSID) and Borrelia Burgdoferi (cutaneous MALT lymphoma) and autoimmune diseases. Adults are predominantly affected. MALT lymphomas respond to radiotherapy and the clinical course is ususally favourable.
MALT of the colon and rectum
Marginal zone B-cell lymphoma of MALTtype (MALT lymphoma) may occur as solitary mass or nodular lesion in the caecum or rectum
Isaacson PG (1999)
. The histological and immunophenotypical features are discussed in detail with tumours of the stomach. Low-grade colorectal MALT lymphomas resemble those of the small intestine in that lymphoepithelial lesions are less prominent than in the stomach. Multiple gastrointestinal involvement of more than one anatomical site is frequent
Gastrointestinal lymphomas of T- and B-cell types.
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Bosman FT, Carneiro F, Hruban RH, Theise ND (Eds.)
WHO Classification of Tumours of the Digestive System.
International Agency for Research on Cancer: Lyon 2010
Other types of marginal zone lymphoma include:
Nodal marginal zone lymphoma (NMZL)
Splenic B-cell marginal zone lymphoma (SMZL)