Secondary Lymphoid Tissues ›› Spleen ›› Normal

Normal Spleen*

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› Microscopic Features:

• Spleen is divided into 2 main zones: Red pulp and white pulp
• The white pulp contains the lymphoid cells and appears as small blue/purple aggregates of lymphoid tissue
• The red pulp contains the sinusoids along with scattered hematopoietic cells and appears red in the image above

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

• PB: N/A
• BM: N/A
• LN: N/A

› May Resemble:

• Normal Lymph Node
• Normal Mucosa Associated Lymphoid Tissue (MALT)

› Differential Diagnoses:

Reactive lymphoid hyperplasia Infection Splenic Marginal Zone Lymphoma Hairy Cell Leukemia Follicular Lymphoma

› Classic Immunophenotype:

• "T"-cells have the "Tiny" CDs: CD2, CD3, CD4, CD5, CD7, CD8
• "B"-cells have the "Bigger" CDs: CD19, CD20, CD22

› Misc:

• In Splenic Marginal Zone Lymphoma, the neoplastic cells involve the white pulp area of the Spleen (as opposed to Hairy Cell Leukemia which involves the red pulp area)