Hematopathology Practice Questions

Q: In the investigation of a patient with suspected essential thrombocythaemia, in which of the following genes may you find abnormalities?

CAL-R. **Explanation:** Essential Thrombocythaemia (ET) is a chronic myeloproliferative neoplasm (MPN) characterized by the autonomous overproduction of platelets [1]. The pathogenesis involves mutations that lead to constitutive activation of the **JAK-STAT signaling pathway**, driving megakaryopoiesis [1]. **1. Why CAL-R is correct:** Approximately 90% of ET cases are driven by one of three "driver mutations": * **JAK2 (V617F):** Present in ~50-60% of cases [1]. * **CALR (Calreticulin):** Found in ~25-30% of cases (specifically in those who are JAK2 negative) [1]. * **MPL:** Found in ~3-5% of cases [1]. **CALR** mutations (typically insertions or deletions in Exon 9) result in a mutant protein that activates the thrombopoietin receptor (MPL), leading to uncontrolled platelet production [1]. **2. Why the other options are incorrect:** * **BCL-2:** An anti-apoptotic protein associated with **Follicular Lymphoma** due to the t(14;18) translocation. * **BCR:** Part of the **BCR-ABL1** fusion gene (Philadelphia chromosome) seen in **Chronic Myeloid Leukemia (CML)** [1]. ET is specifically defined by the *absence* of the BCR-ABL1 rearrangement. * **c-MYC:** A proto-oncogene associated with **Burkitt Lymphoma** due to the t(8;14) translocation. **Clinical Pearls for NEET-PG:** * **Triple Negative ET:** Refers to the ~10% of patients who lack JAK2, CALR, and MPL mutations. * **Morphology:** Bone marrow shows increased numbers of enlarged, mature megakaryocytes with "staghorn" or deeply lobulated nuclei [1]. * **Clinical Feature:** Erythromelalgia (burning pain and erythema of hands/feet) is a classic symptom due to microvascular occlusion. * **Prognosis:** CALR-mutated ET generally has a lower risk of thrombosis compared to JAK2-mutated ET. **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. 627-628.

Q: Pappenheimer bodies are composed of:

Iron. **Explanation:** **Pappenheimer bodies** are abnormal basophilic granules found in red blood cells. They are composed of **ferritin (iron) aggregates** that have not been incorporated into hemoglobin [1]. 1. **Why Iron is Correct:** Under normal conditions, iron is transported to the mitochondria for heme synthesis. When there is iron overload or impaired utilization (as seen in Sideroblastic anemia), non-heme iron accumulates in the mitochondria. On a peripheral smear stained with **Wright-Giemsa**, these appear as small, irregular, dark-blue granules usually located at the periphery of the cell. Their identity as iron is confirmed using the **Prussian Blue (Perls') stain**, where they are referred to as **Siderotic granules**. 2. **Why Other Options are Incorrect:** * **Copper:** While copper deficiency can lead to sideroblastic-like changes, the bodies themselves are not made of copper. * **Lead:** Lead poisoning inhibits heme synthesis and causes **Basophilic Stippling**, which consists of **ribosomal precipitates (RNA)**, not iron. * **Zinc:** Excess zinc can cause a secondary copper deficiency, but it does not form intra-erythrocytic inclusions. **Clinical Pearls for NEET-PG:** * **Differential Diagnosis:** Pappenheimer bodies are most commonly seen in **Sideroblastic anemia**, **Splenectomy** (due to loss of splenic "pitting"), and **Hemolytic anemias**. * **Staining Distinction:** * **Wright-Giemsa:** Called Pappenheimer bodies. * **Prussian Blue:** Called Siderotic granules. * **Comparison:** Do not confuse with **Howell-Jolly bodies** (DNA remnants) or **Heinz bodies** (Denatured hemoglobin, seen in G6PD deficiency). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 658-659.

Q: Which of the following conditions is caused by deletion of all four alpha globin genes?

Hb Bart's. The synthesis of alpha-globin chains is controlled by **four genes** (two on each chromosome 16). The clinical severity of alpha-thalassemia depends directly on the number of deleted genes. **1. Why Hb Bart's is correct:** When **all four alpha-globin genes are deleted (--/--)**, no alpha chains are produced. In the fetus, excess gamma ($̳$) chains (which normally pair with alpha) form tetramers ($̳_4$), known as **Hb Bart's**. This hemoglobin has an extremely high affinity for oxygen, making it useless for oxygen delivery to tissues. This leads to severe intrauterine hypoxia, high-output heart failure, and massive edema, a condition known as **Hydrops Fetalis**, which is usually fatal in utero or shortly after birth. **2. Why the other options are incorrect:** * **Beta thalassemia major:** This is caused by mutations in the **beta-globin genes** on chromosome 11, not alpha-globin deletions [1]. * **HbH disease:** This occurs when **three alpha genes** are deleted (--/-̱). The excess beta ($̲$) chains form tetramers ($̲_4$), known as HbH. It presents as a moderately severe hemolytic anemia. * **Alpha thalassemia trait:** This occurs when **two alpha genes** are deleted (either --/̱̱ or -̱/-̱). Patients are usually asymptomatic with mild microcytosis. **High-Yield Pearls for NEET-PG:** * **Hb Bart's:** ̳_4 tetramers (4-gene deletion). * **HbH:** ̲_4 tetramers (3-gene deletion). * **Heinz Bodies:** Denatured hemoglobin precipitates seen in HbH disease (visualized with supravital stains like Brilliant Cresyl Blue). * **Golf Ball Appearance:** Characteristic appearance of RBCs in HbH disease under supravital staining. * **Cis-deletion (--/̱̱):** More common in Asians; carries a higher risk of Hydrops Fetalis in offspring.

Question 1

In the investigation of a patient with suspected essential thrombocythaemia, in which of the following genes may you find abnormalities?

Accepted Answer

CAL-R

Answer

BCL-2

Answer

BCR

Answer

c-MYC

Question 2

A 40-year-old male presented with massive splenomegaly and mild hepatic enlargement. Peripheral blood film shows cells with hair-like projections that are positive for CD25 and CD103, and negative for CD23. What is the likely diagnosis?

Accepted Answer

Peripheral B-cell neoplasm

Answer

Precursor B-cell neoplasm

Answer

Precursor T-cell neoplasm

Answer

Peripheral T-cell neoplasm

Question 3

Pappenheimer bodies are composed of:

Accepted Answer

Iron

Answer

Copper

Answer

Lead

Answer

Zinc

Question 4

All of the following infections may be transmitted by blood transfusion, except?

Accepted Answer

Dengue virus

Answer

Parvovirus B-19

Answer

Cytomegalovirus

Answer

Hepatitis G virus

Question 5

Which of the following is not a feature of megaloblastic anemia?

Accepted Answer

Reticulocytosis

Answer

Thrombocytopenia

Answer

Megakaryocytes

Answer

Howell-Jolly bodies

Question 6

Bone marrow aspiration is not indicated in which of the following conditions?

Accepted Answer

Thalassemia major

Answer

Megaloblastic anemia

Answer

Idiopathic thrombocytopenic purpura

Answer

Pure red cell aplasia

Question 7

A patient with postpartum hemorrhage had about 2 liters of blood loss. Investigation revealed normal PT and a prolonged aPTT. Which test is used to differentiate between coagulation factor deficiency and a factor inhibitor?

Accepted Answer

Mixing studies

Answer

Tissue thromboplastin inhibition time

Answer

Ecarin clotting time

Answer

Dilute Russel viper venom time

Question 8

At what temperature is blood stored?

Accepted Answer

4°C

Answer

-4°C

Answer

6°C

Answer

8°C

Question 9

Which of the following conditions is caused by deletion of all four alpha globin genes?

Accepted Answer

Hb Bart's

Answer

Beta thalassemia major

Answer

HbH disease

Answer

Alpha thalassemia trait

Question 10

Which of the following is NOT a feature of β thalassemia major?

Accepted Answer

Increased osmotic fragility

Answer

Bone marrow hyperplasia

Answer

Hair–on–end appearance

Answer

Splenomegaly

Hematopathology — MCQs

Hematopathology — MCQs

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