6.2 Acute Leukemia

Question 1

T-ALL

• mnemonic, for location and population
• aka?

Answer 1

• Thymus, teenagers
• aka Acute lymphoblastic lymphoma (b/c leukocytes form a thymic mass, instead of leukocytes floating in blood)

Question 2

Acute promyelocytic leukemia (APL)

-characterized by what genetic translocation?

Answer 2

• t(15:17), translocation of RAR (retinoic acid receptor) from chromosome 17 to 15. RAR disruption blocks maturation of promyelocytes (myeloblasts).

Question 3

Auer rods

Answer 3

• crystal aggregates of MPO
• seen in myeloblasts. presence in blood indicates AML

Question 4

B-ALL

-what are 2 subtypes, their prognosis, and populations

Answer 4

1. 12:21–children, good prognosis
2. 9:22–Philadelphia chromosome. Adults, poor prognosis

Question 4

Acute promyelocytic leukemia (APL)

-tx

Answer 4

-ATRA (all-trans-retinoic acid, a Vit A derivative), binds altered RAR (retinoic acid receptor), allowing promyelocytes to mature.

Question 4

Myelodysplastic syndrome

• complications
• how do pts typically die

Answer 4

• can progress to AML if blasts >20%
• Pts typically die from infection or bleeding

Question 6

what is TdT

Answer 6

-a DNA polymerase, only in lymphoblasts (presence in blood indicates ALL)

Question 7

Why is Acute promyelocytic leukemia (APL) a medical emergency?

Answer 7

-abnormal promyelocytes contain Auer rods, which increase risk of DIC

Question 8

Acute leukemia

• appearance on histology
• can you determine if AML or ALL?

Answer 8

• you see immature blasts in the blood (low cytoplasm, punched out nucleoli)
• cannot tell without staining if AML or ALL

Question 9

Acute leukemia

-main symptoms (3)

Answer 9

1. anemia (hypoxia)
2. thrombocytopenia (bleeding)
3. neutropenia (infections)

Question 11

Acute Lymphoblastic Leukemia

-surface markers for each type

Answer 11

• use surface markers
  1. B-ALL: CD10, 19, 20 classically
  2. T-ALL: range from CD2 - 8

Question 11

B-ALL

-when using chemo, what 2 sites need to be directly injected and why?

Answer 11

-scrotum and brain (blood-scrotum barrier, and BBB)

Question 12

AML

-common population

Answer 12

50-60 years old

Question 13

Acute leukemia

-definition

Answer 13

-accumulation of >20% blasts in bone marrow (normal 1-2%)

Question 14

acute monocytic leukemia

• classic presentation
• how to monoblasts differ from myeloblasts

Answer 14

1. swelling of gums
2. monoblasts lack MPO

Question 15

acute megakaryoblastic leukemia

-assoc with what population

Answer 15

-Down’s syndrome, before age 5

Question 16

Acute Lymphoblastic Leukemia

-most common populations

Answer 16

1. children
2. Down’s syndrome (after 5 years old)

Question 17

Acute leukemia

-2 categories, what are the markers for each

Answer 17

1. AML–MPO positive (Auer rods, crystalized aggregate of MPO)
2. ALL (TdT positive, a DNA polymerase)

Question 18

What leukemia is this?

-increased risk of DIC, so medical emergency

Answer 18

APL

Question 20

Pt with swelling of gums:

-what WBC disorder to suspect?

Answer 20

• acute monocytic leukemia
• remember, monoblasts have no MPO

Question 21

Myelodysplastic syndrome

• what is this, and how does it present?
• exposure to what increases risk?

Answer 21

• preexisting dysplasia of blood cells. usually presents with cytopenias, hypercellular bone marrow, abnormal maturation of cells, and increased blasts (<20%)
• exposure to radiation or alkylating agents increases risk

Question 22

Down’s syndrome:

-what 2 subpopulations are assoc with which 2 WBC disorders?

Answer 22

1. Down’s before age 5: acute megakaryoblastic leukemia (form of AML)
2. Down’s after age 5: ALL