A 64-year-old has a routine CBC with WBC 6.9 × 10^3/µL [6.9 × 10^9/L] and 58% lymphocytes. Flow cytometry shows that 85% of the lymphocytes are CD5+, CD23+ B cells with dim kappa. There is no lymphadenopathy, splenomegaly or cytopenia. The best classification is:

Monoclonal B-cell lymphocytosis

Lymphoid neoplasms: chronic leukemias and lymphomas

10 ASCP MLS practice questions on Lymphoid neoplasms: chronic leukemias and lymphomas, 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 72-year-old man has left upper abdominal fullness, and his spleen is palpable 12 cm below the costal margin; there are no enlarged lymph nodes. Results: WBC 18.6 × 10^3/µL [18.6 × 10^9/L], lymphocytes 74%, monocytes 5%, Hb 10.9 g/dL [109 g/L] and platelets 112 × 10^3/µL [112 × 10^9/L]. Many lymphocytes have short, fine projections clustered at one pole of the cell. Flow cytometry shows a monoclonal B-cell population: CD19+, CD20+ (bright), bright surface IgM kappa, CD5−, CD10−, CD23−, CD103−, CD25−, CD123− and CD11c weakly positive. Cyclin D1 is negative. Which diagnosis fits best?
1. AChronic lymphocytic leukemia
2. BSplenic marginal zone lymphoma
3. CMantle cell lymphoma
4. DHairy cell leukemia
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Answer: B · Splenic marginal zone lymphoma
Massive splenomegaly without lymphadenopathy and lymphocytes with short villi gathered at one pole are typical of splenic marginal zone lymphoma. Its B cells are bright for CD20 and surface immunoglobulin but negative for CD5, CD10, CD23, CD103, CD25 and CD123, and cyclin D1 is not expressed. Hairy cell leukemia also enlarges the spleen, but its projections circle the whole cell, monocytes are very low, and the cells are positive for CD103, CD25, CD123 and bright CD11c. CLL is CD5 and CD23 positive with dim surface immunoglobulin, and mantle cell lymphoma is CD5 and cyclin D1 positive.
- A: CLL cells are CD5 and CD23 positive with dim surface immunoglobulin.
- C: Mantle cell lymphoma is CD5 positive and expresses cyclin D1.
- D: Hairy cells have projections all round the cell, low monocytes, and are CD103, CD25 and CD123 positive.
Question 2 · Hard
A 64-year-old has a routine CBC with WBC 6.9 × 10^3/µL [6.9 × 10^9/L] and 58% lymphocytes. Flow cytometry shows that 85% of the lymphocytes are CD5+, CD23+ B cells with dim kappa. There is no lymphadenopathy, splenomegaly or cytopenia. The best classification is:
1. ASmall lymphocytic lymphoma
2. BChronic lymphocytic leukemia
3. CMonoclonal B-cell lymphocytosis
4. DReactive lymphocytosis
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Answer: C · Monoclonal B-cell lymphocytosis
Absolute lymphocytes = 6.9 × 0.58 = 4.0 × 10^3/µL, and clonal B cells = 4.0 × 0.85 = 3.4 × 10^3/µL [3.4 × 10^9/L]. CLL needs at least 5 × 10^9/L clonal B cells in the blood; below this, without lymph node, spleen or tissue disease or cytopenias, the finding is monoclonal B-cell lymphocytosis. CLL-type MBL with this count progresses to CLL needing treatment at about 1% to 2% a year. The clonal B-cell count, not the total lymphocyte count, decides the category.
- A: Small lymphocytic lymphoma requires lymphadenopathy or other tissue involvement.
- B: CLL requires 5 × 10^9/L or more clonal B cells, and this patient has 3.4.
- D: Light chain restriction shows the B cells are clonal, not reactive.
Question 3 · Easy
CLL cells are monoclonal B cells that characteristically co-express:
1. ACD5 and CD23
2. BCD103 and CD25
3. CCD10 and TdT
4. DCD4 and CD7
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Answer: A · CD5 and CD23
CLL cells are small mature B cells that express CD19, dim CD20, CD5 and CD23, with dim surface immunoglobulin restricted to kappa or lambda. CD5 is normally a T-cell marker, so its presence on B cells is a key clue. Mantle cell lymphoma is also CD5 positive but is usually CD23 negative. FMC7 and CD79b are usually negative or weak in CLL.
- B: CD103 and CD25 are features of hairy cell leukemia.
- C: CD10 and TdT mark B-lymphoblasts.
- D: CD4 and CD7 are T-cell markers.
Question 4 · Easy
Classic hairy cell leukemia carries which mutation in nearly all cases?
1. ACALR exon 9
2. BBRAF V600E
3. CJAK2 V617F
4. DMYD88 L265P
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Answer: B · BRAF V600E
The BRAF V600E mutation is present in almost all cases of classic hairy cell leukemia and is a useful diagnostic marker. It activates the MAPK signaling pathway that drives the hairy cells. Its absence should raise the possibility of a mimic such as splenic marginal zone lymphoma. BRAF inhibitors are an option for relapsed disease.
- A: CALR mutations occur in ET and primary myelofibrosis.
- C: JAK2 V617F is found in myeloproliferative neoplasms such as PV.
- D: MYD88 L265P is typical of Waldenström macroglobulinemia.
Question 5 · Hard
A 56-year-old man has an enlarged spleen and a dry tap marrow. CBC: WBC 1.9 × 10^3/µL [1.9 × 10^9/L], monocytes 0.02 × 10^3/µL [0.02 × 10^9/L], Hb 9.8 g/dL [98 g/L], platelets 72 × 10^3/µL [72 × 10^9/L]. A small B-cell population is CD11c+, CD25+, CD103+, CD123+ and CD5−. Which diagnosis fits best?
1. AChronic lymphocytic leukemia
2. BMantle cell lymphoma
3. CHairy cell leukemia
4. DSplenic marginal zone lymphoma
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Answer: C · Hairy cell leukemia
Pancytopenia with marked monocytopenia, splenomegaly and a dry tap is the classic picture of hairy cell leukemia. Co-expression of CD11c, CD25, CD103 and CD123 on bright CD20 B cells is highly specific, and the cells often show circumferential hairy projections. The dry tap results from reticulin fibrosis around the hairy cells. Annexin A1 and BRAF V600E positivity confirm the diagnosis.
- A: CLL is CD5 and CD23 positive and causes a lymphocytosis.
- B: Mantle cell lymphoma is CD5 positive and cyclin D1 positive.
- D: Splenic marginal zone lymphoma usually lacks CD103 and CD123 and has polar villi.
Question 6 · Medium
A B-cell lymphocytosis that is CD5 positive, CD23 negative and positive for cyclin D1 most likely represents:
1. AChronic lymphocytic leukemia
2. BFollicular lymphoma
3. CMantle cell lymphoma
4. DHairy cell leukemia
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Question 7 · Hard
Blood lymphocytes are small with deeply cleaved nuclei. Flow cytometry: CD19+, CD20+, CD10+, CD5−, with lambda light chain restriction. Which translocation is most likely?
1. At(14;18) IGH::BCL2
2. Bt(8;14) MYC::IGH
3. Ct(9;22) BCR::ABL1
4. Dt(11;14) CCND1::IGH
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Question 8 · Hard
A 70-year-old has red, scaling skin over most of the body (erythroderma). The blood has lymphocytes with folded, cerebriform nuclei, and flow cytometry shows CD3+, CD4+, CD7− and CD26− T cells. The most likely diagnosis is:
1. ASézary syndrome
2. BAdult T-cell leukemia/lymphoma
3. CT-cell prolymphocytic leukemia
4. DT-lymphoblastic leukemia
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Question 9 · Medium
Why is a drop of 22% bovine albumin often mixed with the blood before making a film in CLL?
1. ATo lyse red cells so lymphocytes stand out
2. BTo prevent platelet clumping on the slide
3. CTo improve staining of neutrophil granules
4. DTo reduce smudging of the fragile lymphocytes
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Question 10 · Medium
An older adult has a lymphocytosis of small, mature-looking lymphocytes with many smudge cells. What is the most likely diagnosis?
1. AChronic lymphocytic leukemia
2. BHairy cell leukemia
3. CAcute lymphoblastic leukemia
4. DInfectious mononucleosis
Answer and explanation in LearnFree account

Lymphoid neoplasms: chronic leukemias and lymphomas

A 64-year-old has a routine CBC with WBC 6.9 × 10^3/µL [6.9 × 10^9/L] and 58% lymphocytes. Flow cytometry shows that 85% of the lymphocytes are CD5+, CD23+ B cells with dim kappa. There is no lymphadenopathy, splenomegaly or cytopenia. The best classification is:

CLL cells are monoclonal B cells that characteristically co-express:

Classic hairy cell leukemia carries which mutation in nearly all cases?

A B-cell lymphocytosis that is CD5 positive, CD23 negative and positive for cyclin D1 most likely represents:

Blood lymphocytes are small with deeply cleaved nuclei. Flow cytometry: CD19+, CD20+, CD10+, CD5−, with lambda light chain restriction. Which translocation is most likely?

A 70-year-old has red, scaling skin over most of the body (erythroderma). The blood has lymphocytes with folded, cerebriform nuclei, and flow cytometry shows CD3+, CD4+, CD7− and CD26− T cells. The most likely diagnosis is:

Why is a drop of 22% bovine albumin often mixed with the blood before making a film in CLL?

An older adult has a lymphocytosis of small, mature-looking lymphocytes with many smudge cells. What is the most likely diagnosis?