Hemopath 4 Oncogenic Flashcards
(15 cards)
What distinguishes leukemia from lymphoma in terms of location and cell proliferation?
Leukemia: Malignancy of hematopoietic stem cells primarily in the bone marrow and blood.
Lymphoma: Malignancy of lymphoid cells primarily forming solid tumors in lymph nodes or extranodal sites.
What surface markers help differentiate B and T cells in lymphoid neoplasms?
B cells: CD19, CD20, CD22.
T cells: CD3, CD4 (helper), CD8 (cytotoxic).
What is the significance of smudge cells in hematologic diagnosis?
Smudge cells are fragile, disrupted lymphocytes seen in Chronic Lymphocytic Leukemia (CLL) due to the fragility of neoplastic B cells.
What defines a monoclonal population of lymphocytes and why is this clinically important?
Monoclonality means all cells originate from a single progenitor. It suggests a neoplastic (malignant) rather than reactive (benign) lymphoid proliferation.
What does a ‘starry sky’ appearance on lymph node biopsy suggest, and which lymphoma is it associated with?
It refers to macrophages ingesting apoptotic tumor cells, seen in Burkitt lymphoma. The background of dark lymphocytes is ‘sky’ and pale macrophages are ‘stars.’
What genetic event underlies many lymphoid malignancies, and how is it detected?
Oncogene translocation into immunoglobulin or T-cell receptor loci promotes uncontrolled growth. Detected via FISH, PCR, or karyotyping.
Which translocation is associated with Burkitt lymphoma and what gene is involved?
t(8;14) translocation. Moves the MYC oncogene under control of the Ig heavy chain promoter, leading to overexpression.
What lab findings are common in multiple myeloma?
Elevated monoclonal Ig (M spike) on serum protein electrophoresis.
Hypercalcemia, renal failure, anemia, and lytic bone lesions (CRAB symptoms).
What is the diagnostic hallmark of multiple myeloma in the bone marrow?
Clonal plasma cell proliferation, typically >10% plasma cells in marrow.
What is the clinical relevance of Bence-Jones proteins?
They are free light chains excreted in urine in multiple myeloma, toxic to renal tubules and cause myeloma kidney.
What is the difference between Hodgkin lymphoma and non-Hodgkin lymphoma in terms of cellular features?
Hodgkin lymphoma: Presence of Reed-Sternberg cells (CD15+, CD30+).
Non-Hodgkin: Typically lacks RS cells, more heterogeneous.
How does CLL typically present and progress clinically?
Indolent course with lymphocytosis, smudge cells, hypogammaglobulinemia, and possibly autoimmune cytopenias. May transform into aggressive lymphoma (Richter transformation).
What are Reed-Sternberg cells and what do they indicate?
Large binucleate cells (‘owl eye’ nuclei) seen in Hodgkin lymphoma, derived from B cells but lacking typical B-cell markers.
What immunophenotypic tools are used to diagnose hematologic malignancies?
Flow cytometry to detect CD markers, immunohistochemistry on biopsies, and FISH/PCR for chromosomal rearrangements.
Why is staging important in lymphoma, and what system is used?
Guides treatment and prognosis. Uses the Ann Arbor staging system based on the number and location of affected lymph nodes and extranodal involvement.
