Hematopathology Practice Questions

Q: Paroxysmal Nocturnal Hemoglobinuria (PNH) is screened by which of the following tests?

Acid ham test. **Explanation:** **Paroxysmal Nocturnal Hemoglobinuria (PNH)** is an acquired clonal hematopoietic stem cell disorder caused by a mutation in the **PIGA gene**, leading to a deficiency of GPI-anchored proteins (specifically **CD55 and CD59**). These proteins normally protect RBCs from complement-mediated lysis [1]. 1. **Why Option A is Correct:** The **Acid Ham Test (Acidified Serum Lysis Test)** is the classic confirmatory/screening test for PNH. It relies on the principle that PNH cells are hypersensitive to complement. When the patient's RBCs are placed in acidified serum (pH 6.4), the alternative complement pathway is activated, leading to the lysis of the defective PNH cells. 2. **Why Other Options are Incorrect:** * **Option B:** The **Sucrose Lysis Test** was historically used as a screening test because sucrose promotes the binding of complement to RBCs. However, it is less specific than the Ham test and has been largely phased out. * **Option C & D:** Serum haptoglobin (not hapten) levels are decreased in any intravascular hemolysis, and serum complement levels are typically normal in PNH; these are non-specific findings and not used for screening. **Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** **Flow Cytometry** is now the investigation of choice. It detects the absence of CD55 (DAF) and CD59 (MIRL) on RBCs and leukocytes. * **FLAER (Fluorescent Proaerolysin):** A highly sensitive flow cytometry-based test used to detect the absence of GPI anchors. * **Triad of PNH:** Hemolytic anemia, Pancytopenia, and Venous Thrombosis (often in unusual sites like the Budd-Chiari syndrome). * **Treatment:** **Eculizumab** (a monoclonal antibody against C5 complement) is the drug of choice.

Q: What is the most common cytogenetic abnormality in Multiple myeloma?

Deletion 13q. **Explanation:** Multiple Myeloma (MM) is characterized by a complex landscape of genetic alterations. Understanding the distinction between the "most common" and "prognostically significant" abnormalities is crucial for NEET-PG. **1. Why Deletion 13q is correct:** **Deletion 13q** is the most frequent cytogenetic abnormality in Multiple Myeloma, detected in approximately **50% of cases** by conventional cytogenetics and up to **80-90%** using Fluorescence In Situ Hybridization (FISH). It often involves the loss of the *RB1* (Retinoblastoma) gene and is considered an early event in the pathogenesis of the disease. **2. Analysis of Incorrect Options:** * **Trisomy 12:** This is the most common chromosomal abnormality in **Chronic Lymphocytic Leukemia (CLL)**, not Multiple Myeloma. MM is more commonly associated with odd-numbered trisomies (Hyperdiploidy), such as trisomies of chromosomes 3, 5, 7, 9, 11, and 15. * **t(11;14):** This translocation involves the *CCND1* (Cyclin D1) gene. While it is the most common **translocation** in MM (occurring in ~15% of cases), its overall frequency is lower than Deletion 13q. It is also the hallmark of Mantle Cell Lymphoma. * **t(4;14):** This involves the *FGFR3* and *MMSET* genes. It occurs in about 15% of patients and is significant because it indicates a **poor prognosis**, but it is not the most common. **Clinical Pearls for NEET-PG:** * **Most common overall abnormality:** Deletion 13q. * **Most common translocation:** t(11;14). * **Poor Prognostic Markers (High Yield):** del(17p) [loss of TP53], t(4;14), and t(14;16). * **Good Prognostic Markers:** Hyperdiploidy and t(11;14). * **CRAB Criteria:** Remember **C**alcium (high) [1], **R**enal insufficiency [1], **A**nemia [1], and **B**one lesions [1] for clinical diagnosis. **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. 608-609.

Q: A 6-year-old boy presents with acute abdomen and a nonhealing ulcer on the medial malleolus. A peripheral smear is shown. What is the most likely cause of this condition?

Substitution of a single amino acid base. ***Substitution of a single amino acid base*** - **Sickle cell disease** is caused by a **point mutation** substituting **valine for glutamic acid** at position 6 of the **beta-globin chain**, leading to **HbS formation**. - The clinical presentation of **acute abdomen** (vaso-occlusive crisis) and **medial malleolus ulcer** with **sickle-shaped RBCs** on peripheral smear is pathognomonic for sickle cell disease. *Trinucleotide repeat expansion* - This mechanism causes conditions like **Huntington's disease**, **Fragile X syndrome**, and **myotonic dystrophy**. - These disorders do not present with **hemolytic anemia**, **vaso-occlusive crises**, or **sickle cells** on peripheral smear. *Antibody to red blood cell membrane* - This describes **autoimmune hemolytic anemia** caused by **warm or cold antibodies** against RBC surface antigens. - Would show **spherocytes** and **positive direct Coombs test**, not the **sickle cells** and **leg ulcers** seen in this case. *Genomic imprinting* - This epigenetic mechanism affects conditions like **Prader-Willi syndrome** and **Beckwith-Wiedemann syndrome**. - These disorders involve **growth abnormalities** and **developmental issues**, not **hemolytic anemia** or **vaso-occlusive phenomena**.

Question 1

Pancytopenia with a cellular bone marrow is seen in which of the following conditions?

Accepted Answer

Paroxysmal nocturnal hemoglobinuria (PNH)

Answer

Glucose-6-phosphate dehydrogenase (G6PD) deficiency

Answer

Acquired aplastic anemia

Answer

Thalassemia

Question 2

Paroxysmal Nocturnal Hemoglobinuria (PNH) is screened by which of the following tests?

Accepted Answer

Acid ham test

Answer

Sucrose lysis test

Answer

Serum hapten levels

Answer

Low serum complement levels

Question 3

What is the most common cytogenetic abnormality in Multiple myeloma?

Accepted Answer

Deletion 13q

Answer

Trisomy 12

Answer

Translocation t(4;14)

Answer

Translocation t(11;14)

Question 4

A 59-year-old male presents with multiple neck swellings, fever, and weight loss. He has a history of hypertension. Examination reveals painless lymphadenopathy in the neck, and blood investigations show anemia. Lymph node biopsy shows characteristic 'owl eye' shaped cells. What is the most probable diagnosis for this patient?

Accepted Answer

Hodgkin’s lymphoma

Answer

Multiple myeloma

Answer

Non-Hodgkin’s lymphoma

Answer

Burkitt’s lymphoma

Question 5

Which of the following is the most likely cause of non-megaloblastic macrocytic anemia?

Accepted Answer

Hypothyroidism

Answer

Vitamin B12 deficiency

Answer

Thiamine deficiency

Answer

Folic acid deficiency

Question 6

Which of the following immunohistochemical stains is used for the diagnosis of lymphomas?

Accepted Answer

Leukocyte common antigen

Answer

S-100

Answer

HMB-45

Answer

Cytokeratin

Question 7

Massive transfusion in a previously healthy adult male can cause hemorrhage due to which of the following mechanisms?

Accepted Answer

Dilutional thrombocytopenia

Answer

Increased tissue plasminogen activator (tPA) activity

Answer

Vitamin K deficiency

Answer

Decreased fibrinogen levels

Question 8

Paroxysmal nocturnal hemoglobinuria (PNH) is associated with a deficiency of which of the following?

Accepted Answer

All of the above

Answer

Decay-accelerating factor (DAF)

Answer

Membrane inhibitor of raft-like proteins (MIRL)

Answer

Glycosylphosphatidylinositol (GPI) anchored proteins

Question 9

A 6-year-old boy presents with acute abdomen and a nonhealing ulcer on the medial malleolus. A peripheral smear is shown. What is the most likely cause of this condition?

Accepted Answer

Substitution of a single amino acid base

Answer

Trinucleotide repeat expansion

Answer

Antibody to red blood cell membrane

Answer

Genomic imprinting

Question 10

A 24-year-old woman presents with a 4-day history of earache, increased urine production, a skin rash, bone pain on her scalp, otitis media, dermatitis, and exophthalmos. An X-ray of the scalp shows calvarial bone defects, and a fine-needle aspirate displays numerous eosinophils. Which of the following is the most likely diagnosis?

Accepted Answer

Langerhans cell histiocytosis

Answer

Hodgkin lymphoma

Answer

Malignant melanoma

Answer

Metastatic breast carcinoma

Hematopathology — MCQs

Hematopathology — MCQs

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