Secondary Lymphoid Tissues ›› Lymph Node ›› Neoplastic: Non-Hodgkin Lymphoma Burkitt Lymphoma* Click Here for Full Size Additional Image 1 Additional Image 2 Additional Image 3 › Microscopic Features: "Starry Sky" pattern due to many background apoptotic cells The lymph node is usually effaced (closed subcapsular sinus and loss of follicle architecture) The normal lymphoid tissue is replaced by a diffuse lymphoid proliferation of intermediate sized lymphocytes with a very high mitotic rate › Normal % blood-PB, marrow-BM, lymphoid tissue-LN: PB: N/A BM: N/A LN: N/A › May Resemble: Diffuse Large B-cell Lymphoma Small Lymphocytic Lymphoma Mantle Cell Lymphoma Non-neoplastic reactive Lymph node › Differential Diagnoses: Non-neoplastic reactive Lymph node Small Lymphocytic Lymphoma (SLL: The CLL equavalent in tissue) Mantle Cell Lymphoma Diffuse Large B-cell Lymphoma Follicular Lymphoma › Classic Immunophenotype: CD19+ CD20+ CD10+ BCL2- CD5- Ki67 proliferation index is nearly 100% › Cartoon Image: › Misc: Associated with t(8;14) c-MYC;IgH genes Less commonly associated with other translocations including the light chains (kappa or lambda): t(2:8) or t(8;22)