Secondary Lymphoid Tissues ›› Mucosa-Associated Lymphoid Tissue (MALT) ›› Abnormal

MALT Lymphoma (e.g. Gastric)*


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› Microscopic Features:

• Small- to intermediate-sized lymphocytes (many with monocytoid features which show increased amount of cytoplasm)
• Lymphoepithelial lesions (neoplastic lymphocytes infiltrating and destroying the epithelial glandular tissue)

› Normal % blood-PB, marrow-BM, lymphoid tissue-LN:

• PB: None
• BM: None
• LN: None

› May Resemble:

• H. pylori gastritis
• Follicular Lymphoma [Compare]
• Diffuse Large B-cell Lymphoma [Compare]
• Lymphoplasmacytic lymphoma
• Small Lymphocytic Lymphoma [Compare]
• Mantle Cell Lymphoma [Compare]

› Differential Diagnoses:

Infection (specifically H. Pylori in stomach) Mantle cell lymphoma Follicular lymphoma Lymphoplasmacytic lymphoma Diffuse Large B-cell Lymphoma

› Classic Immunophenotype:

• CD19+
• CD20+
• CD5-
• CD10-
• CD23-
• BCL1-

› Cartoon Image:


› Misc:

• Gastric MALT lymphoma is usually associated with H. pylori Note: Extranodal MALT lymphomas are more common in areas of the body that usually lack normal MALT lymphoid tissue (e.g.gastric, etc.)