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Lymphoma Pathology

Additional Accounting Flashcards




Lymphoma - common sites, def, common types
a malignant neoplasm of cell derived from lymphocytes/lymphocyte precursors
• Sites – where lymphocytes typically reside (lymph nodes, spleen, etc.), but can be basically anywhere
o BALT – bronchus-associated lymphoid tissues
o MALT/GALT – mucosa/gut-associated lymphoid tissues (mostly same thing)
o Other key sites – skin, thymus, bone marrow, blood
• vs. ALL – in ALL, lymphocytes/blasts are in the circulation; in lymphoma, they are in a palpable mass (with exceptions)
• B-cells – more common lymphoma problem in US than T-cells (this lecture focuses on B-cells only)
• Lymph Node Anatomy –
contain cortex, which has lymph node follicles within, comprised of:
o Germinal center – B-cell rich area of lymph node (antigen-stimulated differentiation occurs)
o Mantle zone – Cuff of dark cells around germinal center
o Marginal zone – thinner layer around mantle zone, seen best in spleen
Different types of B-cells (3) - pre, follic, post
• Pre-follicular B-cells – are naïve recirculating B-cells, located in mantle zone or blood; haven’t diff’d
• Follicular B-cells – cells from mantle zone can travel deep into germinal center  differentiate to stim.
o Somatic gene mutation – takes place inside germinal center; can be used to identify follicular
• Post-follicular B-cells – already differentiated memory B-cells, located in marginal zone or in elsewhere
• Pre-follicular B-cell Lymphomas –
include CLL/SLL & mantle cell lymphomas:
o Chronic Lymphocytic Leukemia/Small Lymphocytic Leukemia (CLL/SLL) – since pre-follicular B-cell lymphomas are in the circulation often, they are a leukemia in this sense
 Monoclonal – CLL/SLL presents as excess lymphocytes in blood of same size/shape
 Caveat – morphologically, CLL/SLL appears pre-follicular, but molecular studies indicate some are actually post-follicular. Pre-follicular subtypes have more aggressive course
o Mantle Cell Lymphoma – cells of mantle zone become neoplastic & invade outside of boundary; more aggressive than CLL/SLL; irregularly contoured cells
3 types of follicular B-cell lymphoma
include follicular, large cell, and Burkitt’s lymphoma
o Follicular lymphoma – presents as many invading follicles within a lymph node
 Small “cleaved” cells – if this cell type present in follicle, less aggressive course
 Large “round” cells – more of this cell type present in follicle, prognosis worse but responds to therapy well because dividing faster
o Large cell lymphoma – follicle only contains large “round” cells, can expand out of germ. ctr.
 Prognosis – lymphoma is highly aggressive, but this means Tx can at least work better
 Treatment – aims at killing dividing cells, so works better on aggressive proliferating
o Burkitt’s Lymphoma – incredibly aggressive, increased number of mitotic figures, often EBV association
 Genetic Defect – most commonly t(8;14), treatable b/c of rapid division.
• Post-Follicular B-cell Lymphoma types (2) and features...
include marginal zone lymphoma (MALT) & lymphoplasmacytic
o Marginal Zone lymphoma – pale marginal zone is abnormally expanded
 Spleen, GI Tract “MALT” – common sites of marginal zone lymphomas
 H. pylori – infection by this bug can induce MALT lymphoma
o Lymphoplasmacytic lymphoma – induces syndrome of Waldenstrom’s macroglobulinemia
 Plasma-cell prone – since post-follicular B-cells have differentiated already, some are predisposed to activate into plasma cells  lymphoplasmacytic
 IgM secretion – main initial Ig secreted vs. no IgM in plasmocytoma
 Waldenstrom’s macroglobulinemia – thickened blood due to high Ig secretion
Surface marker study for lymphomas (CLL/SLL VS. Mantle Cell)
CLL/SLL: CD5+, weak CD20/surface Ig, CD23+, cyclin D1 -;
Mantle Cell: POSITIVE for CD5/20/Ig/Cyclin D1 +, negative for CD23 -
CD5 indicates what?
CD5 – normally found on T-cells but pathognomic of B cell lymphomas – CLL/SLL and mantle cell lymphomas
aggressiveness/curability of each:
CLL/SLL, follicular lymphoma, marginal zone, lymphoplasmacytic
Mantle cell lymphoma
Large cell lymphoma
Burkitt’s lymphoma
• Non-aggressive, but incurable – CLL/SLL, follicular lymphoma, marginal zone, lymphoplasmacytic
• Aggressive, incurable – Mantle cell lymphoma
• Aggressive, potential cure – Large cell lymphoma
• Highly aggressive (potential cure) – Burkitt’s lymphoma
QUIZ: Reed-Sternberg Cell/Hodgkin cell - what is it? histology?
neoplastic cell type in disease, often surrounded by inflammation
o Histology – can be bi-lobed nucleus, w/ 2 clear nuclei & 2 dark nucleoli  “Owl’s eye”
o What is it? – a B-cell, but very distinctive shape & properties
Hodgkin's key features: (3)
a clinically & histologically distinct type of lymphoma:
o Contiguous spread – tends to spread contiguously from one lymph node to the next
o Mediastinal mass – common presentation of Hodgkin’s disease
o Inflammatory reaction – histology can show non-neoplastic inflammatory reaction to tumor cell
Classical vs. lymphocyte predominant hodgkin's disease
o Classical Hodgkin’s Disease -
 Nodular sclerosis – most common; lymph nodes have sclerotic nodules
 Mixed cellularity – another type
 Lymphocyte depletion – very rare
o Lymphocyte predominant Hodgkin’s Disease:
 Totally different disease – lymphocyte predominant different from classical!
 Behavior – acts like a low-grade, slowly progressive non-Hodgkin’s lymphoma
prognosis of hodgkin's
• Prognosis – very responsive to therapy, often curable
Diffuse Large B-Cell Lymphoma –
2 main gene expression profiles: Germinal Center (“GC”), “Activated B-cell” (“ABC”)
• Clinical differences based on germinal center versus non-germinal center derivation
• Survival difference is less obvious with the inclusion of monoclonal antibody therapy (rituximab) in DLBCL treatment regimens
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