WBC Neoplasia

Question 1

Lymphoid Neoplasms:

Answer 1

Possess phenotypes (surface markers) of various stages of lymphocyte maturation

* Leukemia –involves bone marrow primarily 
* Lymphoma – forms discrete tissue masses

Question 2

Myeloid Neoplasms:

Answer 2

Neoplasms arise from hematopoietic stem cells of myeloid (erythroid, granulocytic or thrombocytic) linage

• Acute myelogenous leukemias
• Myeloid sarcoma (extramedullary myeloid tumor, granulocytic sarcoma, chloroma)
• Myelodysplastic syndromes (cytopenias)
• Chronic myeloproliferative neoplasms (cytoses)

Question 3

Histiocytic Neoplasms:

Answer 3

Uncommon proliferations of macrophages/dendritic cells
* Langerhans cell histiocytosis
Histiocytic sarcomaInterdigitating dendritic cell sarcomaFollicular dendritic cell sarcoma

Question 4

Etiologic - Pathogenetic Factors in White Cell Neoplasia: Chromosomal translocations and oncogenes

Answer 4

(Dysregulation of normal differentiation/maturation/proliferation
Non-random chromosomal translocations
Oncoproteins created by genomic aberrations often block normal maturation)

2. Inherited genetic factors:
   (Mutations that promote genomic instability (Bloom syndrome, Fanconi anemia, ataxia telagiectasia)
   Down Syndrome and type I neurofibromatosis have associated leukemias)

Question 5

Etiologic - Pathogenetic Factors in White Cell Neoplasia: Inherited genetic factors:

Answer 5

(Mutations that promote genomic instability (Bloom syndrome, Fanconi anemia, ataxia telagiectasia)
Down Syndrome and type I neurofibromatosis have associated leukemias)

Question 6

Etiologic and Pathogenetic Factors in White Cell Neoplasia: Environmental Agents

Answer 6

*Viruses:
*HTLV-1: Adult T-cell leukemia/lymphoma
*Epstein-Barr Virus (EBV): Burkitt Lymphoma (30-40%),
Hodgkin lymphoma (3-40 %), and a few other B-cell and NK cell lymphomas
* KSHV/HHV-8: Body cavity large cell lymphoma (B-cell) = Effusion lymphoma

• Helicobacter pylori: Gastric marginal zone lymphoma = MALT lymphoma
• Gluten sensitive enteropathy: T-cell lymphoma
• Insecticides & Chemical Agents: Predispose to leukemias
• HIV: Clonal B-cell abnormalities
• Smoking: Acute myeloid leukemia risk ↑1.3-2.0x

Question 7

Etiologic and Pathogenetic Factors in White Cell Neoplasia:
Iatrogenic

Answer 7

Radiation Therapy

Chemotherapy

Question 8

Pathogenetic Factors

Answer 8

Chromosomal Translocations and Acquired Mutations

• Genes that play a role in development, growth and survival of the normal counterpart of the tumor (BCL2, BCL10, MALT1)
• Oncogenes that block normal maturation (requirement for bcl-6 to be turned off in order for germinal center B cells to mature to memory B cells)
• Errors occurring during antigen receptor gene rearrangement or antibody diversification (IgH translocations)
  Activation-induced cytosine deaminase → B-cell proliferation → mutations

Question 9

Lymphomas can be distinguished by mechanisms used for survival advantage

Answer 9

Highly proliferative (e.g. Burkitt lymphoma)
Evasion of apoptosis (e.g. chronic lymphocytic leukemia)
Lymphomas with features of both (e.g. mantle cell lymphoma)

Question 10

Malignant Lymphomas- first big split

Answer 10

NON-HODGKIN LYMPHOMAS
85% total
2 major types; B –cell (80-85%) & T-cell/NK -cell
many sub-types

HODGKIN’S LYMPHOMA
15% of total
5 or 6 subtypes

“The various lymphoid neoplasms can only be distinguished based on the appearance and molecular characteristics of the tumor cells”

Question 11

Which leukemias tend to occur in kids?

Answer 11

Burkitt’s and lymphoblastic

hodgekin’s tends to be young adults

Question 12

most common lymphoid neoplasm

Answer 12

Diffuse large B-cell lymphoma

Question 13

T cell markers

Answer 13

CD 1-8

Question 14

B cell associated markers

Answer 14

CD 10, 19, 20, 79a

Question 15

marker for hodgkin lymphoma

Answer 15

CD15

Question 16

NK cell markers

Answer 16

CD16 and 56