Secondary Lymphoid Tissues ›› Lymph Node ›› Neoplastic: Non-Hodgkin Lymphoma

Diffuse Large B-cell Lymphoma*


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› Microscopic Features:

• Sheets or clusters of large (>2.5x the size of a mature lymphocyte or equal or > than the size of a histiocyte) abnormal lymphocytes involving lymph node or other tissue
• As the name suggests, the abnormal lymphocytes diffusely infiltrate the involved tissue (typically lacks a nodular/follicular pattern of growth)

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

• PB: N/A
• BM: N/A
• LN: N/A

› May Resemble:

• Burkitt Lymphoma [Compare]
• Small Lymphocytic Lymphoma [Compare]
• Mantle Cell Lymphoma [Compare]
• Follicular Lymphoma [Compare]
• Non-neoplastic reactive Lymph node [Compare]
• Carcinoma
• Melanoma

› Differential Diagnoses:

Mantle cell lymphoma (blastoid variant) Follicular lymphoma (high grade, e.g. 3B) Burkitt Lymphoma Small Lymphocytic Lymphoma (SLL: The CLL equavalent in tissue) Mantle Cell Lymphoma Non-neoplastic reactive Lymph node Hodgkin Lymphoma

› Classic Immunophenotype:

• CD19+
• CD20+
• CD10+ (Germinal center phenotype)
• CD10-/BCL6-/MUM1+ (Non-Germinal Center phenotype)

› Misc:

• Germinal center phenotype (CD10+) has better prognosis (usually responds better to R-CHOP chemotherapy treatment) Many have variable morphology (some with prominent nucleoli, some with high mitotic rate, etc.) and many present as mass lesions