Hematopathology Practice Questions

Q: Increased LAP score is seen in which of the following conditions?

Myelofibrosis. **Explanation:** The **Leukocyte Alkaline Phosphatase (LAP) score** (also known as the Neutrophil Alkaline Phosphatase/NAP score) measures the activity of the enzyme alkaline phosphatase within the secondary granules of mature neutrophils. It is a classic marker used to differentiate reactive leukocytosis from neoplastic processes [1]. **1. Why Myelofibrosis is Correct:** In **Myelofibrosis** (a Chronic Myeloproliferative Neoplasm), there is an increase in mature, functioning neutrophils [1], leading to an **elevated LAP score**. Other conditions causing an increased score include the Leukemoid reaction [1], Polycythemia Vera, pregnancy, and acute infections. **2. Analysis of Incorrect Options:** * **Chronic Myeloid Leukemia (CML):** This is the most high-yield contrast. In CML, the LAP score is **characteristically low** because the rapidly proliferating neoplastic cells are enzymatically deficient. * **Paroxysmal Nocturnal Hemoglobinuria (PNH):** This is a stem cell defect where cells lack GPI-anchored proteins. Since LAP is a GPI-anchored enzyme, its levels are **decreased** in PNH. * **Megaloblastic Anemia:** This condition typically presents with pancytopenia and hypersegmented neutrophils; however, the LAP score is generally **decreased** or normal. **High-Yield Clinical Pearls for NEET-PG:** * **LAP Score Range:** Normal range is typically **40–100**. * **Increased LAP (>100):** Leukemoid reaction [1], Myelofibrosis [1], Polycythemia Vera, Pregnancy, Cushing’s syndrome. * **Decreased LAP (<40):** CML (most common cause), PNH, Hypophosphatasia, Aplastic anemia, and AML. * **The "CML vs. Leukemoid" Rule:** If a patient has a high TLC and splenomegaly, a **low LAP** points to CML, while a **high LAP** points to a Leukemoid reaction [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 580-616.

Q: Haemophilia B is due to a mutation in the gene corresponding to which coagulation factor?

Factor 9. **Explanation:** Hemophilia is a group of hereditary genetic disorders that impair the body's ability to control blood clotting. **Hemophilia B**, also known as **Christmas Disease**, is caused by a deficiency or mutation in the gene encoding **Coagulation Factor IX (9)**. It is inherited as an **X-linked recessive** trait, primarily affecting males [1]. **Analysis of Options:** * **Factor 9 (Correct):** Deficiency leads to Hemophilia B [1]. Factor IX is a serine protease that, when activated (IXa), forms a complex with Factor VIIIa to activate Factor X in the intrinsic pathway. * **Factor 8 (Incorrect):** Deficiency of Factor VIII causes **Hemophilia A** (Classic Hemophilia) [1]. It is the most common type of hemophilia (80-85% of cases). * **Factor 11 (Incorrect):** Deficiency leads to **Hemophilia C** (Rosenthal Syndrome). Unlike A and B, it is autosomal recessive and often seen in Ashkenazi Jews. * **Factor 7 (Incorrect):** Deficiency causes a rare autosomal recessive bleeding disorder. Factor VII is part of the extrinsic pathway (measured by PT/INR). **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Both Hemophilia A and B are **X-linked recessive** [1]. * **Lab Findings:** Characterized by a **prolonged aPTT** with a **normal PT** and **normal bleeding time** (platelet function is unaffected). * **Clinical Presentation:** Hallmark is **Hemarthrosis** (bleeding into joints, most commonly the knee) and deep muscle hematomas. * **Treatment:** Factor replacement therapy is the mainstay. For Hemophilia B, recombinant Factor IX is used. Unlike Hemophilia A, Desmopressin (dDAVP) is **not** effective for Hemophilia B.

Q: Leukocyte common antigen (CD45) is typically seen in which of the following malignancies?

Lymphoma. **Explanation:** **Leukocyte Common Antigen (CD45)** is a transmembrane glycoprotein found on the surface of almost all **hematopoietic cells** and their precursors [1]. It is the most widely used Immunohistochemistry (IHC) marker to differentiate hematopoietic malignancies from non-hematopoietic tumors (small round blue cell tumors). 1. **Why Lymphoma is Correct:** Lymphomas are malignancies of lymphoid lineage. Since CD45 is expressed on all leukocytes (B-cells, T-cells, NK-cells, and granulocytes), it serves as a **pan-leukocyte marker**. Almost all Non-Hodgkin Lymphomas (NHL) are CD45 positive, making it the primary marker for confirming a lymphoid origin in undifferentiated tumors. 2. **Why Other Options are Incorrect:** * **Ewing Sarcoma:** This is a neuroectodermal tumor characterized by the **CD99 (MIC2)** marker. It is CD45 negative. * **Rhabdomyosarcoma:** A skeletal muscle tumor identified by markers like **Desmin, Myogenin, and MyoD1**. It is CD45 negative. * **Osteosarcoma:** A bone-forming tumor that expresses markers like **SATB2** and Osteonectin. It is CD45 negative. **High-Yield Clinical Pearls for NEET-PG:** * **CD45 Exceptions:** While most lymphomas are CD45+, **Classic Hodgkin Lymphoma (RS cells)** is characteristically **CD45 negative** (but CD15+ and CD30+). * **Small Round Blue Cell Tumors (SRBCT):** In a pediatric patient with an undifferentiated SRBCT, the first step in IHC is usually CD45. If positive, it suggests Lymphoma; if negative, other markers like CD99 (Ewing’s) or Desmin (RMS) are evaluated. * **Lineage Specificity:** CD45 confirms the cell is a leukocyte, but further markers (CD3 for T-cells, CD20 for B-cells) are needed to sub-classify the lymphoma [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 596-598.

Question 1

Which anticoagulant is the preferred choice for performing coagulation studies?

Accepted Answer

Tri-sodium citrate

Answer

EDTA

Answer

Heparin

Answer

Double oxalate

Question 2

Macrophage activation syndrome is characterized by all of the following except which one?

Accepted Answer

Hypoferritinemia

Answer

Hemophagocytosis

Answer

Hypofibrinogenemia

Answer

Hyperglycidemia

Question 3

A 63-year-old man presents with splenomegaly and lymphadenopathy. Immunophenotype was positive for CD19, CD79b, and FMC7. What is the most likely diagnosis?

Accepted Answer

Mantle cell lymphoma (MCL)

Answer

Hairy cell leukemia

Answer

Chronic lymphocytic leukemia (CLL)

Answer

Follicular lymphoma

Question 4

Increased LAP score is seen in which of the following conditions?

Accepted Answer

Myelofibrosis

Answer

Chronic myeloid leukemia

Answer

Paroxysmal nocturnal hemoglobinuria

Answer

Megaloblastic anemia

Question 5

The chromosome on which the Rhesus (Rh) blood group gene is located is?

Accepted Answer

Chromosome 1

Answer

Chromosome 3

Answer

Chromosome 6

Answer

Chromosome 9

Question 6

Glanzmann thrombasthenia is due to a defect in which of the following?

Accepted Answer

Glycoprotein IIb/IIIa complex

Answer

Glycoprotein Ib-IX complex

Answer

CD68

Answer

Von Willebrand factor

Question 7

Spur cell anemia is seen in which of the following conditions?

Accepted Answer

Hepatocellular disease

Answer

Drug-induced anemia

Answer

Renal disease

Answer

Alcoholism

Question 8

Hallmark cells are characteristic findings in which of the following hematological malignancies?

Accepted Answer

Anaplastic large-cell lymphoma

Answer

Diffuse large B-cell lymphoma

Answer

Hodgkin lymphoma

Answer

Hairy cell leukemia

Question 9

Haemophilia B is due to a mutation in the gene corresponding to which coagulation factor?

Accepted Answer

Factor 9

Answer

Factor 8

Answer

Factor 7

Answer

Factor 11

Question 10

Leukocyte common antigen (CD45) is typically seen in which of the following malignancies?

Accepted Answer

Lymphoma

Answer

Ewing sarcoma

Answer

Rhabdomyosarcoma

Answer

Osteosarcoma

Hematopathology — MCQs

Hematopathology — MCQs

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