Hematopathology Practice Questions

Q: In sickle cell anaemia, the defect is in which globin chain?

Beta-globin chain. **Explanation:** Sickle cell anemia (HbS) is an autosomal recessive hemoglobinopathy characterized by a **point mutation** in the **beta ($\beta$)-globin gene** located on chromosome 11. [1] **Why Option B is correct:** The defect involves a single nucleotide substitution (missense mutation) where **Adenine is replaced by Thymine (GAG $\rightarrow$ GTG)**. This results in the substitution of the amino acid **Valine for Glutamic acid** at the **6th position** of the $\beta$-globin chain [1]. This change creates a hydrophobic pocket that causes hemoglobin to polymerize under deoxygenated conditions, leading to the characteristic "sickle" shape of red blood cells [1]. **Why other options are incorrect:** * **Option A:** Defects in the alpha ($\alpha$)-globin chain (located on chromosome 16) are associated with **$\alpha$-Thalassemia**, not sickle cell disease [1]. * **Option C & D:** Sickle cell disease is specifically a $\beta$-chain disorder. While hemoglobin is a tetramer ($\alpha_2\beta_2$), the primary genetic lesion is restricted to the $\beta$-locus [1]. **High-Yield NEET-PG Pearls:** * **Inheritance:** Autosomal Recessive [1]. * **Metabisulfite Test:** Used for screening (induces sickling). * **Electrophoresis:** HbS moves **slowest** towards the anode compared to HbA and HbF (due to loss of negative charge from Glutamic acid). * **Protective Effect:** Heterozygotes (Sickle cell trait) have a selective advantage against *Plasmodium falciparum* malaria. * **Complications:** Vaso-occlusive crises, Autosplenectomy (Howell-Jolly bodies), and Salmonellosis (Osteomyelitis) [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 598-601.

Q: Platelets can be stored at what temperature and for how long?

20-24°C for 5 days. **Explanation:** The correct answer is **A. 20-24°C for 5 days.** **Underlying Medical Concept:** Platelets are unique among blood components because they must be stored at **room temperature (20-24°C)** with **continuous agitation**. Agitation (via a platelet agitator) is crucial to prevent platelet aggregation and to facilitate gas exchange, maintaining a pH above 6.0. If platelets are refrigerated (4-8°C), they undergo "cold-induced activation" and structural changes (becoming spherical), leading to rapid clearance by the recipient's spleen after transfusion. The 5-day limit is strictly enforced primarily due to the **risk of bacterial proliferation**, which is higher at room temperature compared to refrigerated components. **Analysis of Incorrect Options:** * **B & D (8 days):** Extending storage to 8 days significantly increases the risk of life-threatening bacterial sepsis. While some newer technologies (like pathogen reduction or large-volume delayed sampling) can extend shelf life to 7 days, the standard board-exam answer remains 5 days. * **C & D (4-8°C):** This is the storage temperature for **Whole Blood and Packed Red Blood Cells (PRBCs)**. Refrigeration preserves red cell metabolic activity but renders platelets non-functional for transfusion purposes. **High-Yield Clinical Pearls for NEET-PG:** * **Agitation:** Essential to prevent lactic acidosis and maintain platelet viability. * **Bacterial Sepsis:** Platelets are the blood component most commonly associated with transfusion-transmitted bacterial infections (most common: *Staphylococcus epidermidis*). * **Dose:** One unit of Random Donor Platelets (RDP) typically increases the count by 5,000–10,000/µL, whereas one unit of Single Donor Platelets (SDP) increases it by 30,000–60,000/µL. * **Fresh Frozen Plasma (FFP):** Stored at **-18°C or colder** for up to 1 year.

Q: A 50-year-old male presented with left upper quadrant pain. On examination, the spleen was palpable 10 cm below the left costal margin. A peripheral smear is shown. Which of the following immunohistochemical markers is used for the diagnosis of the condition?

Annexin A1. ***Annexin A1*** - **Annexin A1** is the specific immunohistochemical marker for **hairy cell leukemia (HCL)**, which presents with massive splenomegaly and characteristic "hairy cells" on peripheral smear. - It helps distinguish **classic HCL** from **HCL-variant** and other B-cell lymphomas, making it the diagnostic marker of choice. *CD23* - **CD23** is primarily used as a marker for **chronic lymphocytic leukemia (CLL)** and **small lymphocytic lymphoma**. - CLL typically presents with **lymphadenopathy** rather than massive splenomegaly, and lacks the characteristic hairy cell morphology. *CD21* - **CD21** is a marker for **B-cells** and **follicular dendritic cells**, but is not specific for any particular lymphoid malignancy. - It does not help differentiate **hairy cell leukemia** from other B-cell disorders and lacks diagnostic specificity. *Cyclin D1* - **Cyclin D1** is the characteristic marker for **mantle cell lymphoma**, which has a different clinical presentation and morphology. - Mantle cell lymphoma typically affects **elderly males** with lymphadenopathy and **gastrointestinal involvement**, not isolated massive splenomegaly.

Q: A 10-year-old male child presents with pallor and a history of blood transfusion 2 months back. On investigation, Hb is 4.5 gms, total count is 60,000, and platelet count is 2 lakhs. Immunophenotyping shows CD10+, CD19+, CD117+, MPO+, and CD33-. What is the most probable diagnosis?

Mixed phenotypic acute leukemia. **Explanation:** The diagnosis of **Mixed Phenotypic Acute Leukemia (MPAL)** is based on the presence of markers from two different lineages on the same blast population (biphenotypic) or two distinct populations of blasts (bilineal). In this case, the immunophenotype shows a combination of: * **B-cell lineage markers:** CD10 and CD19 [1]. * **Myeloid lineage markers:** MPO (the most specific marker for myeloid differentiation) and CD117. According to the WHO classification, the expression of **MPO** (via flow cytometry or immunohistochemistry) is sufficient to assign a myeloid lineage, while **CD19** (strong) along with other B-markers like **CD10** confirms B-lineage involvement. Since both criteria are met, it is classified as MPAL. **Analysis of Incorrect Options:** * **A. Acute Lymphoblastic Leukemia (ALL):** While CD10 and CD19 are classic B-ALL markers, the presence of MPO and CD117 rules out a pure lymphoid diagnosis [1]. * **B. Acute Myeloid Leukemia (AML):** Although MPO and CD117 are myeloid markers, the strong expression of B-cell markers (CD10, CD19) precludes a diagnosis of pure AML. * **C. Undifferentiated Leukemia:** This diagnosis is reserved for cases where blasts lack any lineage-specific markers (negative for MPO, T-cell, and B-cell markers). **Clinical Pearls for NEET-PG:** * **MPO** is the "gold standard" for myeloid lineage. * For **B-lineage** assignment in MPAL: Strong CD19 + one other B-marker (CD10, CD22, or CD79a) is required. * For **T-lineage** assignment: Cytoplasmic CD3 is the most specific marker. * MPAL generally carries a **poorer prognosis** compared to lineage-specific acute leukemias and often requires more intensive, hybrid chemotherapy protocols. **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. 599-600.

Question 1

Target cells are seen in which of the following conditions?

Accepted Answer

All of the above

Answer

Liver disease

Answer

Post splenectomy

Answer

Thalassemia

Question 2

Bence Jones proteinuria is found on a urinalysis specimen from a 63-year-old woman who is developing chronic renal failure with high serum urea nitrogen and creatinine. A radiograph of the vertebral column demonstrates multiple 1 to 2 cm rounded areas of decreased bone density. The pathological examination from a renal biopsy is likely to show which of the following complications?

Accepted Answer

Amyloidosis

Answer

Pneumocystis carinii pneumonia

Answer

Sclerodactyly

Answer

Chronic myelogenous leukemia

Question 3

In sickle cell anaemia, the defect is in which globin chain?

Accepted Answer

Beta-globin chain

Answer

Alpha-globin chain

Answer

Both globin chains

Answer

None of these

Question 4

A patient presents with a lytic bone lesion. Histology reveals monoclonal plasma cells. Bone marrow biopsy shows less than 10 percent plasma cells, and a small M spike is reported on electrophoresis. Skeletal survey is otherwise unremarkable. What is the most likely diagnosis?

Accepted Answer

Plasmacytoma

Answer

Multiple Myeloma

Answer

Smoldering Myeloma

Answer

Lymphoma

Question 5

Platelets can be stored at what temperature and for how long?

Accepted Answer

20-24°C for 5 days

Answer

20-24°C for 8 days

Answer

4-8°C for 5 days

Answer

4-8°C for 8 days

Question 6

At what concentration of methemoglobin does cyanosis appear?

Accepted Answer

1.5 gm/dL

Answer

5 gm/dL

Answer

2 gm/dL

Answer

12 gm/dL

Question 7

A 50-year-old male presented with left upper quadrant pain. On examination, the spleen was palpable 10 cm below the left costal margin. A peripheral smear is shown. Which of the following immunohistochemical markers is used for the diagnosis of the condition?

Accepted Answer

Annexin A1

Answer

CD23

Answer

CD21

Answer

Cyclin D1

Question 8

Paroxysmal nocturnal hemoglobinuria (PNH) is a disease that results from defects in which of the following?

Accepted Answer

GPI (Glycosylphosphatidylinositol)

Answer

Ankyrin

Answer

Band 3

Answer

Spectrin

Question 9

A 10-year-old male child presents with pallor and a history of blood transfusion 2 months back. On investigation, Hb is 4.5 gms, total count is 60,000, and platelet count is 2 lakhs. Immunophenotyping shows CD10+, CD19+, CD117+, MPO+, and CD33-. What is the most probable diagnosis?

Accepted Answer

Mixed phenotypic acute leukemia

Answer

Acute lymphoblastic leukemia (ALL)

Answer

Acute myeloid leukemia (AML)

Answer

Undifferentiated leukemia

Question 10

An 80-year-old asymptomatic woman on routine examination was detected to have a monoclonal spike on serum electrophoresis (IgG levels 1.5 g/dl). Bone marrow revealed 8% plasma cells. Which of the following represents the most likely diagnosis?

Accepted Answer

Monoclonal gammopathy of unknown significance

Answer

Multiple myeloma

Answer

Indolent myeloma

Answer

Waldenstrom's macroglobulinemia

Hematopathology — MCQs

Hematopathology — MCQs

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