A 35-year-old woman has fever and bone pain. Results: WBC 64.0 × 10^3/µL [64.0 × 10^9/L] with 82% blasts, Hb 8.8 g/dL [88 g/L] and platelets 40 × 10^3/µL [40 × 10^9/L]. The blasts have scant agranular cytoplasm and no Auer rods, and cytochemical myeloperoxidase is negative. Flow cytometry: CD19+ (bright), CD10+, cytoplasmic CD79a+, cytoplasmic CD22+, TdT+, CD34+, CD13+, CD33+ (partial), cytoplasmic MPO−, cytoplasmic CD3−, CD7−, CD14− and CD64−. The best classification is:

AML with minimal differentiation

Mixed-phenotype acute leukemia, B/myeloid

On a Wright-stained film, which feature favors lymphoblasts over myeloblasts?

Several large, prominent nucleoli

Cytoplasm with fine azurophilic granules

Lymphoid neoplasms: acute lymphoblastic leukemia

10 ASCP MLS practice questions on Lymphoid neoplasms: acute lymphoblastic leukemia, part of Hematology. The first 10 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Hard
A 35-year-old woman has fever and bone pain. Results: WBC 64.0 × 10^3/µL [64.0 × 10^9/L] with 82% blasts, Hb 8.8 g/dL [88 g/L] and platelets 40 × 10^3/µL [40 × 10^9/L]. The blasts have scant agranular cytoplasm and no Auer rods, and cytochemical myeloperoxidase is negative. Flow cytometry: CD19+ (bright), CD10+, cytoplasmic CD79a+, cytoplasmic CD22+, TdT+, CD34+, CD13+, CD33+ (partial), cytoplasmic MPO−, cytoplasmic CD3−, CD7−, CD14− and CD64−. The best classification is:
1. AT-lymphoblastic leukemia
2. BAML with minimal differentiation
3. CMixed-phenotype acute leukemia, B/myeloid
4. DB-lymphoblastic leukemia
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Answer: D · B-lymphoblastic leukemia
Bright CD19 with CD10, cytoplasmic CD79a and cytoplasmic CD22, plus TdT and CD34, establishes B lymphoblasts. CD13 and CD33 are often expressed aberrantly in B-lymphoblastic leukemia and do not by themselves assign myeloid lineage. A mixed-phenotype B/myeloid leukemia needs proof of myeloid lineage, meaning myeloperoxidase in the blasts or monocytic differentiation; here MPO is negative by cytochemistry and flow, and CD14 and CD64 are negative. AML with minimal differentiation would lack the B-cell markers, and T-lymphoblastic leukemia needs cytoplasmic CD3. The aberrant myeloid markers are still worth recording, because they help track measurable residual disease.
- A: Cytoplasmic CD3 and CD7 are negative, so the blasts are not T lineage.
- B: The blasts carry a full set of B-cell markers, which AML does not.
- C: Myeloid lineage needs MPO or monocytic differentiation; CD13 and CD33 alone are not enough.
Question 2 · Medium
A 15-year-old boy has a mediastinal mass, a pleural effusion and WBC 118 × 10^3/µL [118 × 10^9/L] with many blasts. The most likely diagnosis is:
1. AB-lymphoblastic leukemia
2. BAcute myeloid leukemia
3. CBurkitt leukemia
4. DT-lymphoblastic leukemia
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Answer: D · T-lymphoblastic leukemia
T-ALL typically affects adolescent and young adult males and often presents with a high white count and an anterior mediastinal (thymic) mass. The mass can compress the airway or superior vena cava, so it is an emergency. T-lymphoblasts arise from thymic precursors, which explains the mediastinal site. Flow cytometry showing cytoplasmic CD3 confirms T lineage.
- A: B-ALL usually affects younger children and rarely causes a mediastinal mass.
- B: AML seldom presents with a thymic mass in a teenager.
- C: Sporadic Burkitt lymphoma usually presents with an abdominal mass.
Question 3 · Hard
End-of-induction flow cytometry MRD testing in B-ALL finds 60 cells with the leukemia-associated phenotype among 400,000 nucleated cells analyzed. Using a positivity cutoff of 0.01%, the result is:
1. A0.15%, MRD positive
2. B0.0015%, MRD negative
3. C0.015%, MRD positive
4. D0.015%, MRD negative
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Answer: C · 0.015%, MRD positive
MRD = 60 ÷ 400,000 = 0.00015, and 0.00015 × 100 = 0.015%. This is above the 0.01% (1 in 10,000) cutoff, so the patient is MRD positive. Slipping a decimal place gives 0.15% or 0.0015%. End-of-induction MRD is one of the strongest predictors of relapse and is used to decide whether to intensify therapy.
- A: 0.15% comes from a decimal error; 60 ÷ 400,000 is 0.015%.
- B: 0.0015% comes from a decimal error; the true value is ten times higher.
- D: 0.015% is above the 0.01% cutoff, so it is positive.
Question 4 · Easy
Which leukemia is the most common in children, with a peak at 2 to 5 years of age?
1. AAcute myeloid leukemia
2. BChronic myeloid leukemia
3. CB-lymphoblastic leukemia
4. DT-lymphoblastic leukemia
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Answer: C · B-lymphoblastic leukemia
ALL is the most common childhood cancer, and about 85% of childhood cases are B-lymphoblastic. Incidence peaks between 2 and 5 years. With modern risk-adapted therapy, about 90% of children survive long term. T-ALL is more common in adolescent boys, and AML is much less common in children.
- A: AML accounts for a minority of childhood leukemia.
- B: CML is rare in children and is mainly a disease of adults.
- D: T-lymphoblastic leukemia makes up only about 15% of childhood ALL.
Question 5 · Medium
On a Wright-stained film, which feature favors lymphoblasts over myeloblasts?
1. ASeveral large, prominent nucleoli
2. BAn Auer rod in the cytoplasm
3. CScant, agranular cytoplasm
4. DCytoplasm with fine azurophilic granules
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Answer: C · Scant, agranular cytoplasm
Lymphoblasts are usually small to medium cells with a high nuclear-to-cytoplasmic ratio, scant blue agranular cytoplasm and inconspicuous nucleoli. Myeloblasts tend to have more cytoplasm, several distinct nucleoli and sometimes fine granules or Auer rods. Morphology alone is not reliable, because some lymphoblasts are large and some myeloblasts lack granules. Flow cytometry is needed to assign lineage.
- A: Several prominent nucleoli are more typical of myeloblasts.
- B: An Auer rod proves myeloid lineage.
- D: Fine azurophilic granules suggest myeloid blasts.
Question 6 · Medium
In adults with B-lymphoblastic leukemia, the most common recurrent genetic abnormality is:
1. AHigh hyperdiploidy
2. Bt(12;21) ETV6::RUNX1
3. Ct(1;19) TCF3::PBX1
4. Dt(9;22) BCR::ABL1
Answer and explanation in LearnFree account
Question 7 · Hard
A 4-month-old has WBC 310 × 10^3/µL [310 × 10^9/L] and CNS involvement. The blasts are CD19+, CD10−, CD15+ and TdT+. The expected genetic finding is:
1. AMYC::IGH, t(8;14)
2. BHigh hyperdiploidy
3. CKMT2A::AFF1, t(4;11)
4. DETV6::RUNX1, t(12;21)
Answer and explanation in LearnFree account
Question 8 · Hard
A 9-year-old boy has an abdominal mass and circulating blasts with deep blue, vacuolated cytoplasm. Flow cytometry: CD19+, CD20+, CD10+, surface IgM kappa+, TdT− and CD34−. Which diagnosis fits best?
1. AB-lymphoblastic leukemia
2. BBurkitt lymphoma
3. CAcute monocytic leukemia
4. DT-lymphoblastic leukemia
Answer and explanation in LearnFree account
Question 9 · Hard
Which flow cytometry profile fits T-lymphoblastic leukemia?
1. ACD3+, CD4+, CD7−, TdT−
2. BCD19+, CD10+, TdT+, cCD3−
3. CCD7+, CD33+, CD117+, MPO+
4. DcCD3+, CD7+, TdT+, MPO−
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Question 10 · Medium
Which genetic finding in childhood B-lymphoblastic leukemia carries the most favorable prognosis?
1. At(12;21) ETV6::RUNX1
2. BKMT2A rearrangement
3. Ct(9;22) BCR::ABL1
4. DHypodiploidy (< 44 chromosomes)
Answer and explanation in LearnFree account

Lymphoid neoplasms: acute lymphoblastic leukemia

A 15-year-old boy has a mediastinal mass, a pleural effusion and WBC 118 × 10^3/µL [118 × 10^9/L] with many blasts. The most likely diagnosis is:

End-of-induction flow cytometry MRD testing in B-ALL finds 60 cells with the leukemia-associated phenotype among 400,000 nucleated cells analyzed. Using a positivity cutoff of 0.01%, the result is:

Which leukemia is the most common in children, with a peak at 2 to 5 years of age?

On a Wright-stained film, which feature favors lymphoblasts over myeloblasts?

In adults with B-lymphoblastic leukemia, the most common recurrent genetic abnormality is:

A 4-month-old has WBC 310 × 10^3/µL [310 × 10^9/L] and CNS involvement. The blasts are CD19+, CD10−, CD15+ and TdT+. The expected genetic finding is:

A 9-year-old boy has an abdominal mass and circulating blasts with deep blue, vacuolated cytoplasm. Flow cytometry: CD19+, CD20+, CD10+, surface IgM kappa+, TdT− and CD34−. Which diagnosis fits best?

Which flow cytometry profile fits T-lymphoblastic leukemia?

Which genetic finding in childhood B-lymphoblastic leukemia carries the most favorable prognosis?