Hematopathology Practice Questions

Q: Stem cells show positivity with which of the following markers?

CD34. **Explanation:** The correct answer is **CD34**. **1. Why CD34 is correct:** CD34 is a transmembrane phosphoglycoprotein primarily expressed on **hematopoietic stem cells (HSCs)** and progenitor cells [1]. It acts as a cell-cell adhesion factor, helping stem cells attach to the bone marrow extracellular matrix or stromal cells. As these cells mature and differentiate into specific lineages, the expression of CD34 is lost. Therefore, CD34 is the gold-standard marker used in flow cytometry to quantify stem cells for **Hematopoietic Stem Cell Transplantation (HSCT)** and to identify blasts in **Acute Leukemias** [1]. **2. Why the other options are incorrect:** * **CD19:** This is a definitive marker for the **B-cell lineage**. It is expressed from the early pro-B cell stage through terminal differentiation into plasma cells (though expression is lost in mature plasma cells). * **CD3:** This is the most specific marker for **T-cells**. It is part of the T-cell receptor (TCR) complex and is expressed on all mature T-lymphocytes. * **CD38:** While found on many immune cells, high expression of CD38 is characteristic of **Plasma cells**. In the context of stem cells, "CD34+ CD38–" is the signature for the most primitive, multipotent hematopoietic stem cells. **High-Yield Clinical Pearls for NEET-PG:** * **Stem Cell Harvest:** A minimum dose of **2 x 10⁶ CD34+ cells/kg** of the recipient's body weight is typically required for successful engraftment [1]. * **Acute Leukemia:** The presence of >20% blasts (often CD34+) in the bone marrow is diagnostic of Acute Leukemia (AML/ALL). * **Other CD34+ cells:** Besides HSCs, CD34 is also expressed by **vascular endothelial cells** and is used as a marker for vascular tumors (e.g., Angiosarcoma, Kaposi Sarcoma). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 584-586.

Q: In a patient with acute leukemia, the immunophenotype pattern is CD 19+ve, CD 10+ve, CD33+ve, and CD 13+ve. What is the probable diagnosis?

Biphenotypic leukemia. ### Explanation **1. Why Biphenotypic Leukemia is Correct:** Biphenotypic Acute Leukemia (BAL), now classified under **Mixed Phenotype Acute Leukemia (MPAL)** by the WHO, occurs when a single population of blasts expresses markers of more than one lineage. In this case, the blasts express **B-lymphoid markers (CD19, CD10)** and **Myeloid markers (CD33, CD13)**. According to the scoring system (EGIL) or WHO criteria, the co-expression of strong lineage-specific markers from two different lineages (B-cell and Myeloid) confirms a mixed phenotype rather than a lineage-restricted leukemia. **2. Why Incorrect Options are Wrong:** * **B. Acute Lymphoblastic Leukemia (ALL):** While CD19 and CD10 are classic B-ALL markers, the significant expression of CD33 and CD13 (myeloid markers) excludes a diagnosis of pure ALL. * **C. AML-M2:** This is a myeloid leukemia characterized by the t(8;21) translocation. While it may occasionally show "lineage infidelity" (like CD19 expression), the presence of strong B-cell markers (CD10/CD19) alongside myeloid markers in a blast population points toward MPAL. * **D. AML-M0:** This is minimally differentiated AML. Blasts are negative for myeloperoxidase (MPO) and typically do not express lymphoid markers like CD10 or CD19. **3. High-Yield Clinical Pearls for NEET-PG:** * **MPAL Definition:** Requires meeting specific criteria for more than one lineage (e.g., MPO for Myeloid; CD19/CD22/CD79a for B-lineage; cytoplasmic CD3 for T-lineage). * **Common Translocations:** MPAL is frequently associated with **t(9;22)** (Philadelphia chromosome) or **MLL gene rearrangements** (11q23). * **Prognosis:** Generally carries a **poorer prognosis** compared to lineage-specific AML or ALL. * **CD10 (CALLA):** A high-yield marker for Common ALL, but its presence alongside myeloid markers is a hallmark of biphenotypic presentation.

Question 1

A 40-year-old male who underwent splenectomy 20 years ago presents for a peripheral blood smear examination. What would be observed?

Accepted Answer

Howell-Jolly bodies

Answer

Dohle bodies

Answer

Hypersegmented neutrophils

Answer

Spherocytes

Question 2

Stem cells show positivity with which of the following markers?

Accepted Answer

CD34

Answer

CD19

Answer

CD3

Answer

CD38

Question 3

What is the most common variant of lymphoma seen in HIV-positive patients?

Accepted Answer

Immunoblastic Lymphoma

Answer

Burkitt's Lymphoma

Answer

Primary CNS Lymphoma

Answer

Mantle Cell Lymphoma

Question 4

In a patient with acute leukemia, the immunophenotype pattern is CD 19+ve, CD 10+ve, CD33+ve, and CD 13+ve. What is the probable diagnosis?

Accepted Answer

Biphenotypic leukemia

Answer

Acute lymphoblastic leukemia (ALL)

Answer

Acute myeloid leukemia - M2 subtype (AML-M2)

Answer

Acute myeloid leukemia - M0 subtype (AML-M0)

Question 5

All are true about hemophilia, except?

Accepted Answer

Increased bleeding time (BT)

Answer

Decreased factor VIII

Answer

Decreased factor IX

Answer

Increased partial thromboplastin time (PTT)

Question 6

Which of the following statements is true about Multiple Myeloma?

Accepted Answer

Monoclonal immunoglobulin (M spike) is increased.

Answer

Plasma cells deposit directly in glomerular capillaries, causing kidney damage.

Answer

Interleukin-8 (IL-8) is a marker for bone lesions.

Answer

Alkaline phosphatase levels are invariably increased.

Question 7

All of the following can cause megakaryocytic thrombocytopenia, except?

Accepted Answer

Aplastic anemia

Answer

Idiopathic thrombocytopenic purpura

Answer

Systemic lupus erythematosus

Answer

Disseminated intravascular coagulation (DIC)

Question 8

Which of the following factors is NOT involved in the intrinsic pathway of coagulation?

Accepted Answer

Factor VII

Answer

Factor XII

Answer

Factor XI

Answer

Factor IX

Question 9

Delayed prolonged bleeding after a minor surgery is caused by a defect in which of the following?

Accepted Answer

Secondary hemostasis.

Answer

Primary hemostasis.

Answer

Defect in the capillary bed to support the clot.

Answer

Defect in connective tissue to support capillaries.

Question 10

All of the following are WHO classified Myelodysplastic Syndromes except:

Accepted Answer

Chronic myeloid leukemia (CML)

Answer

Refractory anemia with excess blasts

Answer

Refractory anemia with ringed sideroblasts

Answer

Refractory anemia

Hematopathology — MCQs

Hematopathology — MCQs

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