Intro to Hematologic Malignancy

Question 1

Terms to describe malignancies of lymphocytes and progenitors

Answer 1

lymphoid, lymphocytic, lymphoblastic, or lymphoproliferative

Question 1

Terms to describe malignancies of myeloid cells

Answer 1

myeloid, myeloproliferative, or myelodysplastic

Question 2

Leukemia vs Lymphoma

Answer 2

Leukemia is applied to neoplasms that typically involve the bone marrow and the peripheral blood, whereas lymphoma is used to describe lymphoid tumors that commonly present as masses within lymph nodes or other soft tissues.

Question 3

Acute vs chronic leukemias

Answer 3

Acute leukemias, if untreated, are lethal within weeks to several months, whereas chronic leukemias may be compatible with survival for many years without treatment.

Question 4

Most important concept for classifying hematologic malignancies

Answer 4

Cell of origin

Question 5

WHO’s five categories of hematologic malignancy

Answer 5

• Acute leukemias
• Myeloproliferative neoplasms
• Myelodysplastic syndromes
• Lymphomas / Lymphoid Leukemias
• Plasma cell neoplasms

Question 6

Acute leukemias

Answer 6

Tumors in which early myeloid or lymphoid progenitors (blasts) accumulate in the bone marrow and to varying degrees spill into the peripheral blood and infiltrate other tissues.

Cells are non-functional and suppress the production of normal hematopoietic elements in the marrow. As a result, most patients present with symptoms related to pancytopenia.

Question 7

Myeloproliferative neoplasms

Answer 7

Tumors that arise in the bone marrow and most commonly lead to the increased production of one or more types of mature myeloid cells. May arise from early myeloid progenitors or hematopoietic stem cells.​

Most symptoms initially stem from the hyperproliferation of bone marrow progenitors and increased numbers of red cells, granulocytes, and/or platelets in the peripheral blood and the spleen.

Question 8

Myelodysplastic syndromes

Answer 8

Heterogeneous group of myeloid tumors in which the maturation of bone marrow progenitors is abnormal (dysplastic) and ineffective. The cell of origin is believed to be an early myeloid progenitor.

Patients present with symptoms related to one or more cytopenias and follow a highly variable course.

Question 9

Lymphomas and lymphoid leukemias

Answer 9

Large, diverse group of tumors derived from mature lymphocytes or their progenitors. Most common hematologic malignancies.

Lymphomas divided into Hodgkin’s (B-cell neoplasms linked by the presence of highly unusual tumor giant cells) and Non-Hodgkin’s.

Aggressive lymphoid neoplasms must be treated as quickly as possible, whereas indolent tumors may wax and wane for years even in the absence of therapy.

Question 10

Plasma cell neoplasms

Answer 10

Composed at least in part of terminally differentiated B cells (plasma cells).

Relatively common tumors occur mainly in older adults and often present with symptoms related to the production of complete or partial immunoglobulins by the tumor cells.

Most important of these tumors are: 1) multiple myeloma, and 2) lymphoplasmacytic lymphoma, in which the tumor cells often produce immunoglobulin M (IgM), sometimes in quantities sufficient to produce a hyperviscosity state called Waldenström macroglobulinemia.

Question 11

Some indolent forms of leukemia and lymphoma commonly . . .

Answer 11

Some indolent forms of leukemia and lymphoma commonly transform into more aggressive forms of disease that fall into a different diagnostic category

Question 12

Diagnostic techniques for leukemias and lymphomas

Answer 12

• Tissue biopsy
• Blood smear
• Bone marrow biopsy and/or aspirate
• Tests for cell clonality (FACS, antibody monoclonality, hypergammaglobulinemia/other antibodies)
• Morphology
• Immunophenotyping (staining for specific lineage markers and/or oncoproteins)
• Histochemistry
• Cytogenetics
• Molecular genetics

Question 13

Key to distinguishing between benign and malignant leukemoid processes

Answer 13

Clonality!

Question 14

Table of blood cancers

Answer 14

Question 15

Why are acute leukemias usually immature cells and chronic leukemias usually mature cells?

Answer 15

Think of it the other way around:

Leukemias of immature cells present acutely because they can still proliferate

Leukemias of mature cells present chronically because they cannot.

Question 16

CD5 on B cells

Answer 16

Not normally expressed on B cells. Is usually a T cell marker. However, B cells express it in two very specific hematologic malignancies, and so it is often screened for by Flow.

Question 17

Blood cancers usually kill by . . .

Answer 17

. . . severe pancytopenia.