Hematopathology Practice Questions

Q: Hemophilia B is due to deficiency of which clotting factor?

Factor IX. **Explanation:** **Hemophilia B**, also known as **Christmas Disease**, is an X-linked recessive bleeding disorder caused by a deficiency or dysfunction of **Clotting Factor IX**. Factor IX is a vitamin K-dependent serine protease essential for the intrinsic pathway of the coagulation cascade. Its deficiency impairs the generation of thrombin, leading to a failure of secondary hemostasis. **Analysis of Options:** * **Factor IX (Correct):** Deficiency leads to Hemophilia B. It is clinically indistinguishable from Hemophilia A but requires specific replacement with Factor IX concentrates. * **Factor VIII (Incorrect):** Deficiency of Factor VIII causes **Hemophilia A** (Classic Hemophilia), which is the most common type of hemophilia (80-85% of cases) [1]. * **Factor VII (Incorrect):** Deficiency leads to a rare autosomal recessive bleeding disorder. Since Factor VII is part of the extrinsic pathway, it is the only deficiency that prolongs PT while keeping aPTT normal. * **Factor X (Incorrect):** Deficiency is a rare autosomal recessive disorder affecting the common pathway, prolonging both PT and aPTT. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Both Hemophilia A and B are **X-linked recessive** (primarily affecting males) [1]. * **Lab Findings:** Characterized by **prolonged aPTT** with a **normal PT, normal bleeding time, and normal platelet count**. * **Mixing Study:** The prolonged aPTT corrects when the patient's plasma is mixed with normal pooled plasma (distinguishes deficiency from inhibitors). * **Clinical Feature:** The hallmark is **Hemarthrosis** (bleeding into joints, most commonly the knee) and muscle hematomas. * **Treatment:** Recombinant Factor IX; unlike Factor VIII, Factor IX has a longer half-life and smaller volume of distribution. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 670-671.

Q: Blast crises in Chronic Myeloid Leukemia (CML) are characterized by which of the following?

Blast cells in blood >= 20%. Chronic Myeloid Leukemia (CML) is a myeloproliferative neoplasm characterized by the Philadelphia chromosome $t(9;22)$. It typically progresses through three distinct phases: the Chronic Phase, the Accelerated Phase, and the **Blast Crisis (Blast Phase)**. **1. Why Option B is Correct:** According to the WHO classification, the **Blast Crisis** is defined by the presence of **$\ge$ 20% blasts** in the peripheral blood or bone marrow [1]. This stage represents the transformation of CML into an acute leukemia [1]. Interestingly, in 70% of cases, the blasts are myeloid (AML-like), while in 30%, they are lymphoid (ALL-like), reflecting the origin of CML in a pluripotent stem cell. **2. Why Other Options are Incorrect:** * **Option A:** A blast count of **10-19%** (along with other criteria like persistent thrombocytopenia or increasing splenomegaly) defines the **Accelerated Phase**, not the Blast Crisis. * **Option C:** Blasts are never absent in CML; even in the Chronic Phase, blasts are typically present but remain $<10\%$. **High-Yield Clinical Pearls for NEET-PG:** * **Defining Genetic Abnormality:** $t(9;22)$ resulting in the *BCR-ABL1* fusion gene, which encodes a constitutively active tyrosine kinase. * **Leukocyte Alkaline Phosphatase (LAP) Score:** Characteristically **decreased** in CML (helps differentiate it from a Leukemoid Reaction where LAP is elevated). * **Basophilia:** An increase in peripheral blood basophils is a hallmark of CML and often heralds progression to the accelerated phase. * **Treatment:** Imatinib (Tyrosine Kinase Inhibitor) is the first-line therapy. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 613-614.

Q: Comment on the type of anemia observed in a peripheral smear.

Pernicious anemia. ***Pernicious anemia*** - Characterized by **macro-ovalocytes** (large, oval-shaped RBCs) and **hypersegmented neutrophils** (>5 nuclear lobes) on peripheral smear. - Results from **vitamin B12 deficiency** due to lack of **intrinsic factor**, leading to megaloblastic anemia with distinctive morphological changes. *Iron deficiency anemia* - Shows **microcytic hypochromic** RBCs with **pencil cells** and **target cells** on peripheral smear. - Associated with **decreased serum ferritin** and **increased TIBC**, not the megaloblastic changes seen in this case. *Sickle cell anemia* - Peripheral smear reveals characteristic **sickle-shaped cells** (drepanocytes) and **target cells**. - Caused by **hemoglobin S mutation**, leading to sickling under hypoxic conditions, not megaloblastic morphology. *Hereditary spherocytosis* - Shows **spherocytes** (round RBCs lacking central pallor) and **increased osmotic fragility** on peripheral smear. - Results from **membrane protein defects** causing loss of membrane surface area, distinct from megaloblastic changes.

Question 1

Hemophilia B is due to deficiency of which clotting factor?

Accepted Answer

Factor IX

Answer

Factor VIII

Answer

Factor VII

Answer

Factor X

Question 2

Which of the following statements regarding umbilical cord banking is FALSE?

Accepted Answer

Blood is collected from the umbilical artery.

Answer

It is used for allogeneic stem cell transplant.

Answer

Transplantation can be done in people with different HLA matching.

Answer

Blood is preserved by cryopreservation.

Question 3

The type of non-Hodgkin's lymphoma with the highest rate of gastrointestinal system involvement is:

Accepted Answer

Extranodal marginal zone B cell lymphoma of MALT type

Answer

B cell chronic lymphocytic leukemia

Answer

Mantle cell lymphoma

Answer

Follicular lymphoma

Question 4

Pancytopenia with a cellular bone marrow is seen in all of the following conditions except:

Accepted Answer

Dyskeratosis congenita

Answer

Paroxysmal nocturnal hemoglobinuria (PNH)

Answer

Megaloblastic anemia

Answer

Myelodysplastic syndrome

Question 5

The Coombs test is used for diagnosing which of the following conditions?

Accepted Answer

Antibody-mediated hemolytic anemia

Answer

Thalassemia

Answer

Sickle cell anemia

Answer

G6PD deficiency

Question 6

Factor IX deficiency results in increased which of the following?

Accepted Answer

Partial Thromboplastin Time (PTT)

Answer

Prothrombin Time (PT)

Answer

Bleeding Time (BT)

Answer

Thrombin Time (TT)

Question 7

Burkitt's lymphoma is positive for which CD marker?

Accepted Answer

CD20

Answer

CD5

Answer

CD15

Answer

CD25

Question 8

Blast crises in Chronic Myeloid Leukemia (CML) are characterized by which of the following?

Accepted Answer

Blast cells in blood >= 20%

Answer

Blast cells in blood or bone marrow > 10%

Answer

Blast cells absent

Answer

All of the above

Question 9

Comment on the type of anemia observed in a peripheral smear.

Accepted Answer

Pernicious anemia

Answer

Iron deficiency anemia

Answer

Sickle cell anemia

Answer

Hereditary spherocytosis

Question 10

Defect leading to thalassemia lies in which component?

Accepted Answer

Hemoglobin

Answer

Osmotic fragility

Answer

RBC membrane

Answer

Platelets

Hematopathology — MCQs

Hematopathology — MCQs

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