Hematopathology Practice Questions

Q: Lethal midline granuloma arises from which cell type?

NK cells. ***NK cells*** - **Lethal midline granuloma**, also known as **extranodal NK/T-cell lymphoma, nasal type**, is **predominantly derived from Natural Killer (NK) cells** in 70-80% of cases. - These malignant NK cells are **CD56 positive** and show a **cytotoxic phenotype** with expression of cytotoxic molecules (granzyme B, perforin, TIA-1). - The disease is strongly associated with **Epstein-Barr virus (EBV)** infection and presents with **destructive midline facial lesions** involving the nasal cavity, paranasal sinuses, and palate. - **Angioinvasion and necrosis** are characteristic histologic features. *T-cells* - While a **minority of cases** (20-30%) can arise from **cytotoxic T-cells** with a similar clinical presentation, NK cell origin is the predominant type. - T-cell derived cases are CD3 positive but CD56 negative, distinguishing them from the more common NK cell type. - The term "NK/T-cell lymphoma" reflects that both origins are possible, but NK cells are the primary cell of origin. *B-cells* - **B-cell lymphomas** are distinct entities that do not typically present as lethal midline granuloma. - B-cell lymphomas may involve extranodal sites but lack the characteristic aggressive destruction of midline facial structures seen in NK/T-cell lymphoma. *Macrophages* - **Macrophages** are phagocytic cells of the mononuclear phagocyte system and are not the origin of lymphomas. - Histiocytic disorders (like Langerhans cell histiocytosis) arise from cells of macrophage/dendritic cell lineage, but these are distinct from lymphoid malignancies.

Q: Which parameter is primarily used to diagnose macrocytosis in a complete blood count (CBC)?

Mean Corpuscular Volume (MCV). ***Mean Corpuscular Volume (MCV)*** - **MCV** measures the **average volume of red blood cells**, making it the primary indicator for classifying them as microcytic, normocytic, or macrocytic. - An **elevated MCV** (typically above 100 fL) indicates **macrocytosis**, meaning the red blood cells are larger than normal. *Mean Corpuscular Hemoglobin Concentration (MCHC)* - **MCHC** reflects the **average concentration of hemoglobin** in red blood cells, primarily used to classify cells as normochromic or hypochromic. - It does **not directly measure cell size** and therefore is not used to diagnose macrocytosis. *Hematocrit* - **Hematocrit** measures the **percentage of red blood cells** in a given volume of blood. - While it indicates the overall red cell mass, it **does not provide information about the average size** of individual red blood cells. *None of the options* - As **MCV** is explicitly listed and is the correct parameter for diagnosing macrocytosis, this option is incorrect. - The other parameters listed are important for other aspects of red blood cell analysis but not for classifying cell size.

Q: Flow cytometry is best used in the measurement of:

CD4+/CD8+ T-cell ratio in AIDS. **CD4+/CD8+ T-cell ratio in AIDS** - **Flow cytometry** is an ideal technique for identifying and quantifying specific cell populations based on their surface markers, like **CD4+** and **CD8+ T-cells**. - Monitoring the **CD4+/CD8+ ratio** is crucial in managing **AIDS** to assess immune status and disease progression. *Serum level of LDH* - **LDH (lactate dehydrogenase)** is an enzyme measured through **biochemical assays** in serum, not flow cytometry. - Flow cytometry measures cellular characteristics, while LDH levels reflect enzyme activity or tissue damage. *To count the RBCs in blood* - While flow cytometry can count cells, a **complete blood count (CBC)**, typically performed by automated hematology analyzers, is the standard and more efficient method for **RBC counting**. - Counting RBCs individually is not the primary or best use case for the advanced capabilities of flow cytometry. *Separation of proteins* - **Protein separation** is achieved through techniques like **electrophoresis**, chromatography, or mass spectrometry, not flow cytometry. - Flow cytometry is designed for analyzing and sorting individual cells or particles, not isolating protein mixtures.

Q: What is the most effective method to prevent transfusion-associated graft-versus-host disease?

Irradiation. Irradiation - **Irradiation** of blood products inactivates donor T-lymphocytes, which are responsible for initiating the immune attack in **transfusion-associated graft-versus-host disease (TA-GVHD)**. - This method is highly effective in preventing TA-GVHD, especially in immunocompromised patients or those receiving blood from biologically related donors. *Washing* - **Washing** removes plasma proteins, antibodies, and some leukocytes but is not effective in removing or inactivating all viable T-lymphocytes that can cause TA-GVHD. - It's primarily used to prevent allergic reactions or to remove excess potassium in certain patient populations. *Chemical treatment* - While experimental chemical treatments for pathogen inactivation exist, there is no widely accepted or clinically proven chemical treatment specifically for preventing **TA-GVHD** by inactivating lymphocytes. - Such methods are not part of routine blood banking practices for this purpose. *None of the options* - This option is incorrect because **irradiation** is a recognized and effective method for preventing **transfusion-associated graft-versus-host disease**.

Q: Which of the following is the most common myeloproliferative disorder?

Essential Thrombocythemia. ***Essential Thrombocythemia*** - **Essential thrombocythemia (ET)** is the **most common myeloproliferative neoplasm**, with an incidence of approximately 1.5-2.4 per 100,000 per year. - It is characterized by **persistent thrombocytosis** (platelet count >450,000/μL) and megakaryocytic proliferation [1]. - Commonly associated with **JAK2 V617F mutation** (~55-60%), **CALR mutations** (~25-30%), and **MPL mutations** (~3-5%) [2]. *Polycythemia rubra vera* - **Polycythemia vera (PV)** is the **second most common** classic MPN, with an incidence of approximately 0.8-2.3 per 100,000 per year. - Characterized by increased red blood cell mass, often with leukocytosis and thrombocytosis [1]. - Strongly associated with **JAK2 V617F mutation** (present in >95% of cases) [2][3]. *CML* - **Chronic myeloid leukemia (CML)** has similar incidence to PV (approximately 1-2 per 100,000 per year). - Defined by the presence of the **Philadelphia chromosome (BCR-ABL1 fusion gene)** [2]. - Treated distinctly with tyrosine kinase inhibitors (TKIs). *Myelofibrosis* - **Primary myelofibrosis (PMF)** is the **least common** of the classic MPNs, with an incidence of approximately 0.3-1.5 per 100,000 per year. - Characterized by bone marrow fibrosis, extramedullary hematopoiesis, and splenomegaly [3]. - Associated with **JAK2, CALR, or MPL mutations** [2]. **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. [2] 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. 624. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 614-615.

Q: Dohle bodies are characteristically seen in which hereditary condition?

May-Hegglin anomaly. ***May-Hegglin anomaly*** - **Dohle bodies** are characteristic inclusions in neutrophils, formed by aggregates of **rough endoplasmic reticulum**, and are a defining feature of **May-Hegglin anomaly**. - This condition also presents with **macrothrombocytopenia** and a tendency for bleeding, along with the presence of these distinctive inclusions. *Infections* - While infections can cause **toxic granulation** and sometimes **Dohle bodies** in neutrophils, they are not considered a hereditary condition. - The Dohle bodies seen in infections are typically transient and not associated with macrothrombocytopenia. *Burns* - Similar to infections, severe burns can induce **toxic changes** in neutrophils, including the formation of Dohle bodies. - However, burns are an acquired condition and not a hereditary disorder, nor are they typically associated with the other features of May-Hegglin anomaly. *Myelodysplastic syndrome* - This is a clonal hematopoietic stem cell disorder characterized by **ineffective hematopoiesis** and **dysplastic changes** in myeloid cells. - While various abnormalities can be seen in neutrophils in MDS, **Dohle bodies** as a characteristic hereditary feature are not typically associated with it; instead, other dysplastic features like hypogranulation or pseudo-Pelger-Huët anomaly are more common.

Q: Hemophilia B is a deficiency of which factor?

IX. ***IX*** - Hemophilia B, also known as **Christmas disease**, is caused by a deficiency in **Factor IX** [1]. - This condition is an **X-linked recessive disorder** that impairs the blood's ability to form clots, leading to prolonged bleeding [1]. *XII* - Deficiency in **Factor XII** (Hageman factor) is usually **asymptomatic** and does not lead to a bleeding disorder. - Individuals with Factor XII deficiency often have a **prolonged aPTT** but no clinical bleeding. *VIII* - A deficiency in **Factor VIII** causes **Hemophilia A**, which is the more common form of hemophilia [1]. - Hemophilia A also presents with bleeding symptoms, but it is distinct from Hemophilia B due to the specific factor involved [1]. *X* - Deficiency in **Factor X** (Stuart-Prower factor) is a rare **autosomal recessive** bleeding disorder. - Factor X deficiency affects both the intrinsic and extrinsic coagulation pathways, leading to prolongation of both **PT and aPTT**.

Question 1

Lethal midline granuloma arises from which cell type?

Accepted Answer

NK cells

Answer

B-cells

Answer

T-cells

Answer

Macrophages

Question 2

Which parameter is primarily used to diagnose macrocytosis in a complete blood count (CBC)?

Accepted Answer

Mean Corpuscular Volume (MCV)

Answer

Hematocrit

Answer

Mean Corpuscular Hemoglobin Concentration (MCHC)

Answer

None of the options

Question 3

Flow cytometry is best used in the measurement of:

Accepted Answer

CD4+/CD8+ T-cell ratio in AIDS

Answer

Serum level of LDH

Answer

To count the RBCs in blood

Answer

Separation of proteins

Question 4

What is the most effective method to prevent transfusion-associated graft-versus-host disease?

Accepted Answer

Irradiation

Answer

Washing

Answer

Chemical treatment

Answer

None of the options

Question 5

Which of the following is the most common myeloproliferative disorder?

Accepted Answer

Essential Thrombocythemia

Answer

Polycythemia rubra vera

Answer

CML

Answer

Myelofibrosis

Question 6

Myeloid sarcoma, which is a tumor mass consisting of myeloid blasts occurring at anatomic sites other than the bone marrow, is often characterized by chromosome aberrations. Which of the following is NOT typically associated with myeloid sarcoma?

Accepted Answer

t (15;17)

Answer

Monosomy 7

Answer

Trisomy 8

Answer

inv (16)

Question 7

Dohle bodies are characteristically seen in which hereditary condition?

Accepted Answer

May-Hegglin anomaly

Answer

Infections

Answer

Burns

Answer

Myelodysplastic syndrome

Question 8

What is the most common type of acute myeloid leukemia in patients with Down's syndrome?

Accepted Answer

Acute megakaryoblastic leukemia M7

Answer

Acute myeloid leukemia M1

Answer

Acute promyelocytic leukemia M3

Answer

Acute myeloid leukemia M2

Question 9

Which of the following statements on lymphoma is not true?

Accepted Answer

In general, follicular (nodular) NHL has worse prognosis compared to diffuse NHL.

Answer

HD more often tends to remain localized to a single group of lymph nodes and spreads by contiguity.

Answer

Several types of non-Hodgkin's lymphoma (NHL) may have a leukemic phase.

Answer

A single classification system for Hodgkin's disease (HD) is almost universally accepted.

Question 10

Hemophilia B is a deficiency of which factor?

Accepted Answer

IX

Answer

XII

Answer

VIII

Answer

X

Hematopathology — MCQs

Hematopathology — MCQs

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