Secondary Lymphoid Tissues ›› Lymph Node ›› Normal

Normal Lymph Node*


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› Microscopic Features:

• An encapsulated lymphoid tissue (as opposed to Mucosa Associated Lymphoid Tissue, also known as MALT)
• Comprised of follicles (primary and secondary) and interfollicular areas
• B-cells mostly reside in the follicles while T-cells mostly reside in between the follicles (interfollicular areas)
• Most of the follicles are located within the cortex

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

• PB: N/A
• BM: N/A
• LN: N/A

› May Resemble:

• Non-neoplastic Lymphadenitis [Compare]
• Follicular Lymphoma [Compare]

› Differential Diagnoses:

Reactive lymphoid hyperplasia Infectious Lymphadenitis 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

› Cartoon Image:


› Misc:

• In a normal lymph, the primary follicles (not antigen stimulated and no germinal center) and secondary follicles (antigen stimulated with a germinal center) are where most B-cell reside The interfollicular (between follicles) areas are where most T-cells reside In summary: B-cells mostly reside in the follicles while T-cells mostly reside in between the follicles (interfollicular areas)