Question 1

B-lymphoblasts in ALL exhibit which one of the following markers that is helpful in their identification?

Accepted Answer

CD10 is a marker that is commonly expressed on B-lymphoblasts, making it a useful tool in their identification in cases of acute lymphoblastic leukemia (ALL). CD4 and CD2 are markers associated with T-cell populations, and HLA-DR is a marker that is expressed on a wide range of cells involved in the immune response.

Question 2

Which of the following markers would be helpful in differentiating cortical T-cell ALL from medullary T-cell ALL?

Accepted Answer

CD1a is typically expressed on cortical T-cell ALL cells but not on medullary T-cell ALL cells. Therefore, its expression can help differentiate between the two subtypes. The other markers listed are not specific to either subtype.

Question 3

Which of the following cytochemical stains would be most helpful in differentiating AML from ALL?

Accepted Answer

Myeloperoxidase (MPO) is a cytochemical stain that is positive in myeloid cells but negative in lymphoid cells. Therefore, it can be helpful in differentiating between Acute Myeloid Leukemia (AML) and Acute Lymphoblastic Leukemia (ALL). AML would be MPO positive, while ALL would be MPO negative. The other stains listed (LAP, PAS, Wright's) are not specific to either myeloid or lymphoid cells.

Question 4

A peripheral blood smear from a patient with acute leukemia displayed a homogeneous population of small blasts with scanty cytoplasm. Based on this information, which WHO classification is described?

Accepted Answer

The homogeneous population of small blasts with scanty cytoplasm is classic for acute lymphoblastic leukemia (ALL). APL would be characterized by large abnormal promyelocytes, AML would have a heterogeneous population of blasts, and information is not adequate to classify the leukemia would have insufficient information to make a diagnosis.

Question 5

Which of the following patient populations is most commonly afflicted with ALL?

Accepted Answer

ALL (Acute Lymphoblastic Leukemia) is most commonly found in children, particularly between the ages of 2-5 years old. While it can occur in adults and other age groups, it is most prevalent in children.

Question 6

ALL most often arises from a defect in which of the following?

Accepted Answer

ALL (acute lymphoblastic leukemia) most often arises from a defect in CLP (common lymphoid progenitor), which is a precursor cell in the development of lymphocytes.

Question 7

The most common translocation found in childhood B-cell ALL is:

Accepted Answer

The most common translocation found in childhood B-cell Acute Lymphoblastic Leukemia (ALL) is t(12;21)(p13;q22), which results in the TEL-AML1 fusion gene. This translocation is associated with a relatively good prognosis.

Question 8

The WHO defines acute lymphoblastic leukemia as having a blast count that is which of the following?

Accepted Answer

The WHO defines acute lymphoblastic leukemia as having a blast count of ≥20%.

Question 9

A patient, 2 years of age, presents with general fatigue, pallor, fever, and weight loss. The morphological exam reveals a normal leukocyte count, marked neutropenia, and thrombocytopenia with 35% blasts. A bone marrow smear reveals hypercellularity with neoplastic lymphoid cells. What immunophenotypic testing would be indicated for this patient?

Accepted Answer

The presentation of the patient is consistent with acute lymphoblastic leukemia (ALL), which is characterized by neoplastic lymphoid cells. Immunophenotyping is crucial in determining the specific subtype and guiding treatment. The markers CD2, CD3, CD5, CD7, and CD19 are commonly used in the diagnosis of ALL and would be appropriate for this patient. CD33 and CD34 are markers commonly used in acute myeloid leukemia (AML), CD11c and CD117 are markers for mast cell disorders, and CD19, CD20, CD22, and Ig genes are markers for B-cell lymphoma/leukemia.

Question 10

A patient has been diagnosed with B-cell ALL. Immunophenotyping has been ordered to confirm the subtype. Which marker would help differentiate Pre-B-cell ALL from Pro-B-cell ALL?

Accepted Answer

CD10 is expressed on pre-B-cells, but not pro-B-cells, therefore if CD10 is positive, it confirms a diagnosis of Pre-B-cell ALL.

Question 11

The most common form of ALL relapse in children is:

Accepted Answer

The answer of The most common form of ALL relapse...

Question 12

Which markers are found on lymphoblasts?

Accepted Answer

CD10, CD19, and HLA-DR are all commonly expressed on lymphoblasts, making D the best choice.

Question 13

Which of the following is an expected finding in the peripheral blood smear of an ALL patient?

Accepted Answer

A decreased platelet count is commonly observed in acute lymphoblastic leukemia (ALL) patients due to bone marrow infiltration by leukemic cells, which disrupts normal hematopoiesis including platelet production.

Question 14

As part of their disease progression, ALL patients are at risk for developing which of the following?

Accepted Answer

ALL patients are at risk for developing recurrent infections due to a compromised immune system, bleeding episodes due to low levels of platelets, and fatigue due to anemia.

Question 15

A 5-year-old patient has been diagnosed with Pre-B-cell ALL. Routine cytogenetic analysis confirms the presence of the Philadelphia chromosome. What does this mean for the patient?

Accepted Answer

The Philadelphia chromosome is a genetic abnormality found in some cases of acute lymphoblastic leukemia (ALL) and is associated with a poor prognosis. It results from a translocation of genetic material between chromosomes 9 and 22, leading to the creation of the BCR-ABL1 fusion gene. This gene produces a protein that promotes the growth and survival of cancer cells. Patients with ALL who have the Philadelphia chromosome generally require more aggressive treatment and have a higher risk of treatment failure and relapse.

Question 16

An immunoglobulin (Ig) gene rearrangement can be identified in all of the following acute lymphoblastic leukemias except:

Accepted Answer

Precursor T acute lymphoblastic leukemia does not involve Ig gene rearrangements, as T cells do not produce immunoglobulins. The other types of acute lymphoblastic leukemias (Pro-B, Common ALL, Pre-B) involve Ig gene rearrangements because they originate from B cells, which produce immunoglobulins.

Question 17

What cytochemical stains are negative in ALL but positive in AML?

Accepted Answer

Nonspecific esterase and myeloperoxidase are cytochemical stains that are typically negative in Acute Lymphoblastic Leukemia (ALL) but positive in Acute Myeloid Leukemia (AML), helping to differentiate between these two types of leukemia.

Question 18

A phenotype workup is performed on a patient suspected to have ALL. The results indicate that some of the leukemic cells express myeloid markers, whereas others express T-cell markers. What is the most likely reason for this occurrence?

Accepted Answer

The expression of both myeloid and T-cell markers in the leukemic cells suggests that the patient has bilineage acute leukemia, in which the malignant cells have features of both myeloid and lymphoid lineages. This is different from unilineage acute leukemia, in which the malignant cells only express markers of one particular lineage. The presence of both types of markers is unlikely to be due to mixing of patient samples or interpretation errors.

Question 19

A technologist is reviewing a patient's blood smear. She notices that 85% blasts are present but is having a difficult time identifying the lineage. Cytochemical staining is subsequently performed, and the results for MPO, SBB, NSE, and PAS are negative. Based on this information, what is the most likely lineage of the unknown blasts?

Accepted Answer

The answer of A technologist is reviewing a patient's blood...

Question 20

Which of the following is a classic morphologic finding in the peripheral blood in ALL?

Accepted Answer

In ALL, there is a proliferation of lymphoblasts which leads to decreased numbers of normal blood cells. Therefore, the classic morphologic finding in the peripheral blood in ALL is lymphoblasts, decreased platelets, and decreased neutrophils (choice B). Increased WBC and platelets with increased lymphoblasts (choice A) and lymphoblasts with increased platelets and neutrophils (choice C) are not classic findings in ALL. Choice D, increased WBC, platelets, and neutrophils, is not a typical finding in ALL and suggests a different type of leukemia or a reactive process.

Quiz 27: Precursor Lymphoid Neoplasms