Hematopathology Practice Questions

Q: Duffy antigen is associated with which Cluster of Differentiation?

CD234. The **Duffy antigen**, also known as the Duffy Antigen Receptor for Chemokines (DARC), is a glycoprotein expressed on the surface of red blood cells (RBCs) and endothelial cells. In the Cluster of Differentiation (CD) nomenclature, it is designated as **CD234**. **1. Why CD234 is Correct:** CD234 acts as a multi-ligand receptor for various chemokines. Its primary clinical significance in hematopathology lies in its role as the portal of entry for **Plasmodium vivax** merozoites [1]. Individuals who are "Duffy-negative" (Fy a-b-) lack this receptor on their RBCs, providing them with natural resistance against *P. vivax* malaria. This phenotype is highly prevalent in West African populations. **2. Analysis of Incorrect Options:** * **CD123:** This is the **IL-3 receptor alpha chain**. It is a high-yield marker for **Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN)** and is also expressed in Hairy Cell Leukemia. * **CD345 and CD456:** These are **distractor options**. The current CD nomenclature officially extends to approximately CD371. Numbers in the 300s and 400s are either recently assigned or do not exist in standard medical curricula, making them common "filler" options in competitive exams. **Clinical Pearls for NEET-PG:** * **Malaria Link:** Duffy-negative status protects against *P. vivax* but **not** *P. falciparum* [1]. * **Chemokine Sink:** CD234 on endothelial cells acts as a "sink" to clear inflammatory chemokines from circulation. * **Genetics:** The Duffy gene is located on **Chromosome 1**. * **Transfusion Medicine:** Anti-Fya and Anti-Fyb antibodies are clinically significant and can cause Delayed Hemolytic Transfusion Reactions (DHTR). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 398-400.

Q: What is the characteristic shape of Birbeck granules?

Tennis racket. **Explanation:** **Birbeck granules** are the pathognomonic ultrastructural hallmark of **Langerhans Cell Histiocytosis (LCH)**. These are rod-shaped, pentalaminar cytoplasmic organelles with a central striated line and a bulbous end, giving them a classic **tennis racket** appearance under electron microscopy [1]. They are formed by the invagination of the cell membrane and are associated with the protein **Langerin (CD207)**, which is involved in antigen processing [1]. **Analysis of Options:** * **Option D (Tennis racket):** This is the correct description. The "handle" of the racket is the rod-like portion, and the "head" is the dilated vesicular end [1]. * **Option A (Hockeystick):** This is a distractor. While some granules might appear slightly curved, "tennis racket" is the standard medical descriptor. * **Option B (Bat):** Incorrect. This does not describe the specific pentalaminar structure seen on EM. * **Option C (Ball):** Incorrect. Birbeck granules are elongated rods, not spherical structures. **High-Yield Clinical Pearls for NEET-PG:** * **Cell of Origin:** Langerhans cells (dendritic cells of the skin/monocyte-macrophage lineage). * **Immunohistochemistry (IHC) Markers:** LCH cells are characteristically positive for **S-100**, **CD1a**, and **Langerin (CD207)** [1]. CD207 is the most specific marker. * **Clinical Presentation:** Can range from a solitary bone lesion (Eosinophilic Granuloma) to multisystem involvement (Letterer-Siwe disease). * **Radiology:** Often presents as "punched-out" lytic lesions in the skull. **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. 630.

Q: What type of RBC is typically seen in chronic renal failure?

Normocytic. **Explanation:** The hallmark of anemia in Chronic Renal Failure (CRF) is a **Normocytic Normochromic Anemia**. **Why Normocytic is Correct:** The primary cause of anemia in CRF is the **deficiency of Erythropoietin (EPO)** [2]. EPO is a glycoprotein hormone produced by the peritubular interstitial cells of the kidney [2], [3]. As renal parenchyma is lost, EPO production decreases, leading to reduced stimulation of the bone marrow to produce red blood cells [2]. Since the defect lies in the *quantity* of cells produced rather than the *quality* of hemoglobin synthesis or cell division, the resulting RBCs are normal in size (normocytic) and color (normochromic). **Why other options are incorrect:** * **Microcytic:** This is typically seen in Iron Deficiency Anemia (IDA). While CRF patients may develop IDA due to chronic blood loss (hemodialysis or GI bleeds) or functional iron deficiency (hepcidin-mediated), the classic, primary presentation of renal anemia remains normocytic [1]. * **Macrocytic:** This is characteristic of Vitamin B12 or Folate deficiency. While malnutrition can occur in uremic patients, it is not the standard hematological profile of renal failure itself. **High-Yield Clinical Pearls for NEET-PG:** * **Target Hemoglobin:** In patients on EPO therapy for CRF, the target Hb is usually **10–11.5 g/dL**. Aiming for normal levels (>13 g/dL) increases the risk of stroke and cardiovascular events (CHOIR and CREATE trials). * **Burr Cells (Echinocytes):** These are small, spiked RBCs often seen on the peripheral smear of uremic patients. * **Resistance to EPO:** The most common cause of a poor response to exogenous EPO in CRF patients is **Iron Deficiency** [1]. Always check ferritin and TSAT levels before starting EPO.

Question 1

In Burkitt's lymphoma, which chromosomal translocation is typically seen?

Accepted Answer

t(8;14)

Answer

t(12;14)

Answer

t(4;8)

Answer

t(12;18)

Question 2

All are important laboratory features of hemolytic anemia, EXCEPT:

Accepted Answer

Normal AST

Answer

Elevated urobilinogen in stool

Answer

Reduced haptoglobin

Answer

Macrocytes in blood smear

Question 3

Duffy antigen is associated with which Cluster of Differentiation?

Accepted Answer

CD234

Answer

CD123

Answer

CD345

Answer

CD456

Question 4

A 63-year-old man presented with massive splenomegaly, lymphadenopathy, and a total leukocyte count of 17,000 per mm³. Flow cytometry showed CD23-negative and CD5-positive monoclonal B-cells with bright kappa positivity, comprising 80% of the peripheral blood lymphoid cells. What is the most likely diagnosis?

Accepted Answer

Mantle cell lymphoma

Answer

Splenic lymphoma with villous lymphocytes

Answer

Follicular lymphoma

Answer

Hairy cell leukemia

Question 5

Basophilic stippling is seen in which of the following cells?

Accepted Answer

RBCs

Answer

Eosinophils

Answer

Basophils

Answer

Neutrophils

Question 6

Examination of a peripheral blood smear demonstrates a leukemia composed of small mature lymphocytes without blast forms. Which of the following is the most likely age of this patient?

Accepted Answer

65 years

Answer

1 year

Answer

45 years

Answer

5 years

Question 7

Golf ball inclusion bodies in RBCs are seen in which condition?

Accepted Answer

HbH disease

Answer

Normal reticulocytes

Answer

Pernicious anaemia

Answer

G6PD deficiency

Question 8

D-Dimer values may be increased in all of the following conditions except?

Accepted Answer

Anticoagulant therapy

Answer

Myocardial infarction

Answer

Pneumonia

Answer

Pregnancy

Question 9

What is the characteristic shape of Birbeck granules?

Accepted Answer

Tennis racket

Answer

Hockeystick

Answer

Bat

Answer

Ball

Question 10

What type of RBC is typically seen in chronic renal failure?

Accepted Answer

Normocytic

Answer

Microcytic

Answer

Macrocytic

Answer

None of the above

Hematopathology — MCQs

Hematopathology — MCQs

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