Acute Leukemia

Question 1

Describe basic principles of acute leukemia. Typical presentations. Mechanism. Histo findings.

Answer 1

Neoplastic prolif. of blasts. Definition: accum of >20% blasts in BM. Acute anemia, thrombocytopenia, and neutropenia (infection). Blasts crowd out normal hematopoiesis. Blasts enter blood stream resulting in leukocytosis, seen with punchedout nucleoli

Question 2

What are the two divisions of acute leukemia?

Answer 2

Acute Lymphoblastic (ALL) and Acute Myeloid (AML)

Question 3

What cells accumulate in ALL? What markers are used to characterize lymphoblasts? How is ALL subdivided?

Answer 3

> 20% lymphoblasts in BM; Positive nuclear staining for DNA polymerase TdT; B cell-ALL and T cell-ALL

Question 4

What population is most commonly affected by ALL? What condition is ALL associated with?

Answer 4

Arises in children > 5 yo; Down syndrome

Question 5

Which subtype of ALL is most common?

Answer 5

B cell-ALL

Question 6

Markers for B cell-ALL, Tx, Prognosis

Answer 6

TdT+ lymphoblasts that express CD10, 19, 20; ChemoTx with scrotal and CSF prophylaxis; t(12;21) good (seen in children), t(9;22) poor (seen in adults; Ph+ ALL)

Question 7

Markers for T cell-ALL, presentation

Answer 7

TdT+ lymphoblasts with markers ranging CD2-8; Teenagers with mediastinal thymic mass, called acute lymphoblastic lymphoma because malignant cells form a mass

Question 8

What cells accumulate in AML? What markers are used to characterize myeloblasts? What structures are these makers seen as? Typical population effected?

Answer 8

Immature myeloid cells >20% in BM; Myeloperoxidase (MPO) seen as Auer Rods; Adults 50-60 yo

Question 9

3 classifications of AML

Answer 9

cytogenetic abnormalities, lineage of myeloblasts, surface markers

Question 10

What is APL? What chromosomal abnormality is it characterized by? What cells accumulate? What is a patient with APL at increased risk for? Why? Tx?

Answer 10

Acute promyelocytic leukemia. t(15:17) retinoic acid receptor (17) onto 15. Abnormal RAR blocks promyelocyte maturation. Promyelocytes. Promyelocytes increase risk of DIC because of primary granules. All-trans-retinoic acid binds to altered RAR and causes promyelocyte to mature

Question 11

What is acute monocytic leukemia? What cells accumulate? What marker do the cells NOT have? Typical infiltration site?

Answer 11

Proliferation of monoblasts; usually lack MPO; Gums; Think guy from the Goonies.

Question 12

What is acute megakaryoblastic leukemia? What marker does it lack? What condition and age is the disease associated with?

Answer 12

Proliferation of megakaryoblasts that lack MPO; Down syndrome children< 5 yo

Question 13

In what other situations may AML also arise? Presentation? Reasons for death?

Answer 13

Pre-existing dysplasia (myelodysplastic syndromes) esp. w/ exposure to alkylating agents/RTx; Cytopenia, hypercellular bone marrow, abnormal maturation of cells and increased blasts (< 20%); Most infection or bleeding, some progress to acute leukemia