Hematopathology Practice Questions

Q: Which CD marker represents the leucocyte common antigen?

CD 45. ### Explanation **Correct Option: D (CD 45)** CD 45 is known as the **Leucocyte Common Antigen (LCA)**. It is a transmembrane protein tyrosine phosphatase expressed on the surface of **all hematopoietic cells**, except for mature erythrocytes and platelets. In diagnostic pathology, CD 45 is the primary immunohistochemical (IHC) marker used to differentiate **lymphomas/leukemias** from non-hematopoietic tumors like carcinomas or sarcomas. **Analysis of Incorrect Options:** * **A. CD 14:** This is a specific marker for **monocytes and macrophages**. It acts as a co-receptor for bacterial lipopolysaccharide (LPS). * **B. CD 15:** This marker is expressed on **Reed-Sternberg cells** (in classical Hodgkin Lymphoma, along with CD 30) and is also found on mature **granulocytes**. * **C. CD 23:** This is a low-affinity IgE receptor [1]. It is a key marker for **B-cell Chronic Lymphocytic Leukemia (CLL)** and is used to differentiate it from Mantle Cell Lymphoma (which is CD 23 negative) [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Pan-B cell markers:** CD 19, CD 20 [1]. * **Pan-T cell markers:** CD 3 (most specific), CD 2, CD 5, CD 7 [1]. * **NK cell markers:** CD 16, CD 56. * **Hairy Cell Leukemia:** Characterized by CD 11c, CD 25, and CD 103 [1]. * **Stem cell marker:** CD 34 (used to identify blasts in acute leukemia). * **Memory Tip:** If a tumor is "LCA positive," think Lymphoma; if "Cytokeratin positive," think Carcinoma. **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, p. 598.

Q: The presence of the Philadelphia chromosome is associated with a worse prognosis in patients with which of the following diseases?

Acute lymphoblastic leukemia. **Explanation:** The **Philadelphia chromosome (Ph+)**, resulting from the reciprocal translocation **t(9;22)(q34;q11)**, creates the **BCR-ABL1** fusion gene. This gene encodes a constitutively active tyrosine kinase that drives uncontrolled cellular proliferation. **1. Why Acute Lymphoblastic Leukemia (ALL) is the correct answer:** In ALL, the Philadelphia chromosome is found in approximately 25-30% of adults and 3-5% of children. Historically, Ph+ ALL was associated with a **very poor prognosis**, characterized by low remission rates and high relapse risk [1]. While the introduction of Tyrosine Kinase Inhibitors (TKIs) like Imatinib has improved outcomes, it remains a high-risk feature that often necessitates intensive chemotherapy followed by Allogeneic Stem Cell Transplant. **2. Analysis of Incorrect Options:** * **B. Acute Myelogenous Leukemia (AML):** Ph+ AML is rare (<1%). While it indicates a poor prognosis, it is not the classic association tested in the context of prognostic stratification compared to ALL. * **C. Chronic Lymphocytic Leukemia (CLL):** The Philadelphia chromosome is not a feature of CLL. Common cytogenetic markers in CLL include del(13q), del(11q), and del(17p). * **D. Chronic Myelogenous Leukemia (CML):** The Philadelphia chromosome is the **hallmark** of CML (present in >95% of cases) and is essential for its diagnosis. It defines the disease rather than indicating a "worse prognosis" relative to other CML cases. **High-Yield Clinical Pearls for NEET-PG:** * **Molecular Weight:** In CML, the BCR-ABL protein is typically **p210**, whereas in Ph+ ALL, it is more commonly **p190**. * **Treatment:** The standard of care for Ph+ leukemias involves **TKIs** (Imatinib, Dasatinib, Nilotinib). * **Most Common Translocation in Childhood ALL:** t(12;21) (ETV6-RUNX1), which carries a **favorable** prognosis.

Question 1

Which CD marker represents the leucocyte common antigen?

Accepted Answer

CD 45

Answer

CD 14

Answer

CD 15

Answer

CD 23

Question 2

Bence Jones proteinuria may be seen in:

Accepted Answer

Mu heavy chain disease

Answer

Alpha heavy chain disease

Answer

Gamma heavy chain disease

Answer

Epsilon heavy chain disease

Question 3

The presence of the Philadelphia chromosome is associated with a worse prognosis in patients with which of the following diseases?

Accepted Answer

Acute lymphoblastic leukemia

Answer

Acute myelogenous leukemia

Answer

Chronic lymphocytic leukemia

Answer

Chronic myelogenous leukemia

Question 4

Which of the following is NOT a characteristic feature of multiple myeloma?

Accepted Answer

Hypercalcemia

Answer

Hyperuricemia

Answer

Increased serum alkaline phosphatase

Answer

Monoclonal M band

Question 5

Splenic auto-infarction is typically seen in which of the following conditions?

Accepted Answer

Sickle cell disease

Answer

Splenic amyloidosis

Answer

Thalassemia

Answer

Gaucher disease

Question 6

Raised aPTT is seen in all of the following bleeding disorders except?

Accepted Answer

Henoch-Schonlein purpura

Answer

Hemophilia A

Answer

Hemophilia B

Answer

Von-Willebrand disease

Question 7

What is the biochemical marker of lymphocytic leukemia?

Accepted Answer

Periodic acid-Schiff (PAS) stain

Answer

Enolase

Answer

Peroxidase

Answer

Choline esterase

Question 8

Cytogenetic studies in a 40-year-old woman with follicular lymphoma demonstrate a t(14;18) chromosomal translocation involving the bcl-2 gene. Constitutive expression of the protein encoded by the bcl-2 gene inhibits which of the following processes in this patient's transformed lymphocytes?

Accepted Answer

Apoptosis

Answer

DNA excision repair

Answer

G1-to-S cell cycle progression

Answer

Oxidative phosphorylation

Question 9

A 15-year-old boy presented with a one-day history of bleeding gums, subconjunctival bleed, and purpuric rash. Investigations revealed the following results: Hb-6.4 gm/dL, TLC-26,500/mm3, Platelet - 35,000 mm3, Prothrombin time-20 sec (control of 13 sec), Partial thromboplastin time-50 sec, and Fibrinogen 10 mg/dl. Peripheral smear was suggestive of acute myeloblastic leukemia. Which of the following is the most likely diagnosis?

Accepted Answer

Promyelocytic leukemia

Answer

Myeloblastic leukemia without maturation

Answer

Myeloblastic leukemia with maturation

Answer

Myelomonocytic leukemia

Question 10

Which functional test assesses primary hemostasis?

Accepted Answer

Bleeding time

Answer

Activated partial thromboplastin time

Answer

Platelet count

Answer

Prothrombin time

Hematopathology — MCQs

Hematopathology — MCQs

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