Malt

Mucosa associated lymphoid tissue is found in mucosal areas (including conjunctiva). The mucosa, along with the skin, are the main entry points for antigens. Lymphocytes sensitized in these areas migrate to regional lymph nodes and then return to their original "homing" sites or to other mucosal areas in a stimulatory manner.

Class A immunoglobulins are preferentially produced in the mucosal areas.

"Extranodal marginal zone lymphomas of MALT type B" originate from the MALT system. They account for approximately 7% to 8% of newly diagnosed non-Hodgkin lymphomas. MALT lymphomas can occur in almost any organ (Raderer M et al 2016). Relative to the total population of all marginal zone lymphomas, extranodal marginal zone lymphoma (MALT lymphoma) affects approximately 50-70% of all marginal zone lymphomas, followed by splenic (approximately 20%) and nodal marginal zone lymphoma (approximately 10%).

MALT lymphomas affect the following regions:

• Stomach (36-67%)
• Intestine (3-5%)
• Lung - BALT=Bronchus-associated lymphatic tissue (5-11%)
• Eye appendages (6-22%)
• Skin - SALT=Skin-associated lymphatic tissue (2-9%)
• Thyroid gland (1-3%)
• mamma (2-3%)

1. Defrancesco I et al. (2017) Overview on the management of non-gastric MALT lymphomas. Best Pract Res Clin Haematol 31:57-64.