CH6 - 2) Acute Leukemia

Question 1

What is acute leukemia?

Answer 1

Neoplastic proliferation of blasts; defined as the accumulation of >20% blasts in the bone marrow.

Question 2

What is the acute presentation for acute leukemia?

Answer 2

Anemia (fatigue), thrombocytopenia (bleeding), or neutropenia (infection)

Question 3

What is the reason for the acute presentation of acute leukemia?

Answer 3

Increased blasts crowd-out normal hematopoiesis,

Question 4

In acute leukemia, why is there a high WBC count?

Answer 4

Blasts usually enter the blood stream, resulting in a high WBC count

Question 5

Describe blasts.

Answer 5

they are large, immature cells, often with punched out nucleoli

Question 6

What is acute leukemia subdivided into?

Answer 6

acute lymphoblastic leukemia (ALL) or acute myelogenous leukemia (AML)

Question 7

The subdivision of acute leukemia is based on what?

Answer 7

the phenotype of the blasts.

Question 8

What is acute lymphoblastic leukemia?

Answer 8

Neoplastic accumulation of lymphoblasts (> 20%) in the bone marrow

Question 9

Why is TdT useful in characterizing lymphoblasts?

Answer 9

It is absent in myeloid blasts and mature lymphocytes.

Question 10

Acute lymphoblastic leukemia most commonly arises in whom?

Answer 10

children

Question 11

What is acute lymphoblastic leukemia associated with and when does it usually arise?

Answer 11

Down syndrome (usually arises after the age of 5 years)

Question 12

Acute lymphoblastic leukemia is subclassified into? What is it based on?

Answer 12

B-ALL and T-ALL based on surface markers

Question 13

What is the most common type of ALL?

Answer 13

B-ALL

Question 14

What is B-ALL usually characterized by?

Answer 14

lymphoblasts (TdT+) that express CD10, CD19, and CD20.

Question 15

What is the treatment for B-ALL?

Answer 15

Excellent response to chemotherapy; requires prophylaxis to scrotum and CSf

Question 16

What is the prognosis B-ALL based on?

Answer 16

It is based on cytogenetic abnormalities,

Question 17

Which B-ALL has a good prognosis and is more commonly seen in children?

Answer 17

t(12;21)

Question 18

Which B-ALL has a poor prognosis and in what population is it seen?

Answer 18

t(9;22) has a poor prognosis; more commonly seen in adults (Philadelphia+ALL)

Question 19

What is T-ALL characterized by?

Answer 19

lymphoblasts (TdT+) that express markers ranging from CD2 to CDH (e.g., CD3, CD4, CD7). The blasts do not express CD10.

Question 20

How does T-ALL usually present?

Answer 20

Usually presents in teenagers as a mediastinal (thymic) mass (called acute lymphoblastic lymphoma because the malignant cells form a mass)

Question 21

What is acute myeloid leukemia?

Answer 21

Neoplastic accumulation of myeloblasts (> 20%) in the bone marrow

Question 22

How are myeloblasts usually characterized?

Answer 22

by positive cytoplasmic staining for myeloperoxidase (MPO)

Question 23

What may be seen in the characterization of myeloblasts?

Answer 23

Crystal aggregates of MPO may be seen as Auer rods

Question 24

In whom does acute myeloid leukemia most commonly arise?

Answer 24

older adults (average age is 50-60 years)

Question 25

What is the subclassification of AML based on?

Answer 25

cytogenetic abnormalities, lineage of myeloblasts, and surface markers.

Question 26

What are the high-yield subtypes?

Answer 26

Acute promyelocytic leukemia, Acute monocytic leukemia and acute megakaryoblastic leukemia

Question 27

What is acute promyelocytic leukemia characterized by?

Answer 27

t(15;17), which involves translocation of the retinoic acid receptor (RAR) on chromosome 17 to chromosome 15

Question 28

What is the effect of RAR disruption?

Answer 28

It blocks maturation and promyelocytes (blasts) accumulate

Question 29

How does acute promyelocytic leukemia lead to increased risk for DIC?

Answer 29

Abnormal promyelocytes contain numerous primary granules that increase the risk for DIC

Question 30

What is the treatment for acute promyelocytic leukemia?

Answer 30

with all-trans retinoic acid (ATRA, a vitamin A derivative)

Question 31

How does ATRA work?

Answer 31

It binds the altered receptor and causes the blasts to mature (and eventually die)

Question 32

What is acute monocytic leukemia?

Answer 32

Proliferation of monoblasts; usually lack MPO

Question 33

In acute monocytic leukemia what do blasts characteristically do?

Answer 33

infiltrate gums

Question 34

What is acute megakaryoblastic leukemia?

Answer 34

Proliferation of megakaryoblasts; lack MPO

Question 35

What is acute monocytic leukemia associated with?

Answer 35

Down syndrome (usually arises before the age of 5)

Question 36

What is myelodysplastic syndrome?

Answer 36

acute myeloid leukemia may also arise from pre-existing dysplasia = myelodysplastic syndromes, especially with prior exposure to alkylating agents or radiotherapy

Question 37

What do myelodysplastic syndromes usually present with?

Answer 37

cytopenias, hypercellular bone marrow, abnormal maturation of cells, and increased blasts < 20%

Question 38

With myelodysplastic syndromes resulting in acute myeloid dysplastic syndrome what do most patients die from?

Answer 38

Most patients die from infection or bleeding, though some progress to acute leukemia.