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Primary extranodal lymphomas are special
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May arise in any organ outside the lymph nodes
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The histopathological lymphoma subtypes occur in distinct patterns in
different extranodal sites
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E.g., Marginal zone lymphoma most common in stomach, T-cell lymphomas most common
in skin, diffuse large B-cell lymphoma (DLBCL) most common in tonsils
•
The particular site of extranodal involvement may be associated to the
etiology
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E.g., gastric lymphomas associated with H. pylori infection
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The particular site of extranodal involvement is important for prognosis and
management, independent of the importance of the histologic subtype
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E.g., DLBCL: in the brain (long-term survival in less than 25%), the tonsils (80-90%), and
the testes (40-50%)