Hematopathology Practice Questions

Q: Direct Coombs test is positive in all EXCEPT:

G6PD deficiency. ***G6PD deficiency*** - **G6PD deficiency** is an intrinsic red blood cell defect that leads to hemolytic anemia, but it does **not involve immune-mediated destruction** of red blood cells. - The **Direct Coombs test** detects antibodies or complement components bound to the surface of red blood cells; since G6PD deficiency is not immune-mediated, the test will be negative. *Rh incompatibility* - **Rh incompatibility** occurs when maternal antibodies cross the placenta and target fetal red blood cells, leading to **immune-mediated hemolysis** [1]. - The anti-D antibodies bind to fetal red blood cells, resulting in a **positive Direct Coombs test** (detecting antibody-coated fetal RBCs) [1]. *Autoimmune hemolysis* - **Autoimmune hemolysis** involves the body producing **autoantibodies** against its own red blood cells, leading to their premature destruction [3]. - These autoantibodies (e.g., IgG, IgM) bind to the red blood cell surface, making the **Direct Coombs test positive** [3]. *ABO incompatibility* - **ABO incompatibility** involves the presence of naturally occurring antibodies (e.g., anti-A, anti-B) in a recipient's plasma that react with donor red blood cells [2]. - When incompatible red blood cells are transfused, or in cases of **hemolytic disease of the newborn** due to ABO incompatibility, antibodies bind to the RBCs, resulting in a **positive Direct Coombs test** [2].

Q: What is the primary site of involvement in multiple myeloma?

Bone marrow. ***Bone marrow*** - Multiple myeloma is a **B-cell malignancy** characterized by the uncontrolled proliferation of **plasma cells** in the bone marrow [1]. - These malignant plasma cells produce an abnormal **monoclonal immunoglobulin** (M protein) and can cause lytic bone lesions [2]. *Lungs* - While lung involvement can occur in advanced or unusual cases of multiple myeloma (e.g., through extramedullary plasmacytomas), it is **not the primary site** of the disease. - Primary lung malignancies or metastases from other cancers are more common causes of lung pathology. *Liver* - **Liver infiltration** by myeloma cells is rare and usually indicates widespread disease or extramedullary involvement, not the initial or primary site. - The liver's primary role in hematologic malignancies often involves metabolism or effects on coagulation, not as a primary site of plasma cell proliferation. *Spleen* - **Splenomegaly** can sometimes be observed in multiple myeloma due to extramedullary hematopoiesis or infiltration, but it is **not the primary site** for plasma cell proliferation. - Lymphomas and leukemias are more typically associated with primary splenic involvement. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 616-618. [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, pp. 606-608.

Q: Which of the following statements about sickle cell disease is true?

Autosomal recessive. ### Autosomal recessive - Sickle cell disease is inherited in an **autosomal recessive pattern**, meaning an individual must inherit two copies of the abnormal gene (HbS) to develop the disease. - This mode of inheritance is crucial for genetic counseling and understanding family risk. [1] ### Sickled cells are flexible - **Sickled cells are rigid** and inflexible, unlike normal red blood cells, which contributes to their inability to easily pass through small blood vessels. [1] - Their stiffness is a key factor in the pathology of vaso-occlusion, as they tend to clog capillaries. ### Vaso-occlusion is rare - **Vaso-occlusion is a hallmark** and frequent complication of sickle cell disease, leading to painful crises and organ damage. [1] - The rigid, sickled red blood cells block blood flow in small vessels, causing ischemia and infarction in various tissues. ### Chronic hemolysis does not occur - **Chronic hemolysis is a prominent feature** of sickle cell disease, as the sickled red blood cells are fragile and have a shortened lifespan, leading to constant destruction. [1] - This ongoing destruction of red blood cells causes **anemia**, jaundice, and can contribute to gallstone formation. [1]

Q: Which protein is a key marker of Reed-Sternberg cells in Hodgkin's lymphoma?

CD15. ***CD15*** - **CD15** (along with **CD30**) is a characteristic **immunophenotypic marker** of **Reed-Sternberg cells** in **classical Hodgkin's lymphoma** [1]. - The classic immunophenotype is **CD30+/CD15+/CD45-/CD20-** (CD20 may be weakly positive in some cases). - **CD30 is the most sensitive marker** (positive in >95% of cases), while **CD15 is positive in 75-85%** of classical Hodgkin's lymphoma cases. - Both markers together aid in the definitive diagnosis and differentiation of Hodgkin's lymphoma from other lymphomas. *CD19* - **CD19** is an important **B-cell marker** expressed on normal B lymphocytes and in most B-cell non-Hodgkin lymphomas, but it is typically **negative** in Reed-Sternberg cells [1]. - Its presence usually points away from Hodgkin's lymphoma and towards a B-cell lineage malignancy. *CD20* - **CD20** is another key **B-cell marker** found on the surface of normal B lymphocytes and **most B-cell non-Hodgkin lymphomas**. - Reed-Sternberg cells usually **lack CD20 expression** (or show only weak positivity in 20-40% of cases), helping to distinguish Hodgkin's lymphoma from B-cell non-Hodgkin lymphomas [1]. *CD45* - **CD45** (also known as leukocyte common antigen, LCA) is expressed on nearly all **hematopoietic cells**, including most lymphomas. - However, **Reed-Sternberg cells are typically negative or only weakly positive for CD45**, which is a significant diagnostic feature that helps differentiate Hodgkin's lymphoma from many non-Hodgkin lymphomas [1]. **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. 614-618.

Q: A 50-year-old male presents with fatigue and generalized lymphadenopathy. A lymph node biopsy reveals a starry sky pattern. What is the most likely diagnosis?

Burkitt lymphoma. ***Burkitt lymphoma*** - Characterized by a **starry sky pattern** on histology due to numerous **macrophages** engulfing apoptotic cells [1], commonly associated with a **MYC** mutation. - Typical clinical presentations include **fast-growing lymphadenopathy** and possible **abdominal masses**, aligning with the patient's symptoms of fatigue and lymphadenopathy. *Diffuse large B-cell lymphoma* - Typically shows a variety of cellular patterns but does not exhibit the distinct **starry sky** pattern. - Often presents with **more aggressive symptoms** and is associated with **B symptoms** like fever and night sweats, which are not mentioned here. *Follicular lymphoma* - Histologically presents with **follicles and centrocytes**, differing from the **starry sky pattern** seen in Burkitt lymphoma. - Generally involves **indolent** symptoms, often more chronic than the acute presentation observed in this patient. *Hodgkin lymphoma* - Characterized by **Reed-Sternberg cells** and typically shows a **continuous** pattern of lymph node involvement, unlike the **starry sky** pattern. - Usually associated with **B symptoms** like fever and weight loss, which are not reported in this case. **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. 606.

Q: A 6-year-old boy presents with a rapidly enlarging jaw mass. Histology reveals a 'starry sky' appearance. What is the most likely diagnosis?

Burkitt lymphoma. ***Burkitt lymphoma*** - Characterized by a **rapidly enlarging jaw mass** [1] and the presence of a **'starry sky' appearance** [2] on histology due to interspersed macrophages in a background of dense, proliferative B-lymphoid tissue. - Most common in children [1], often associated with **endemic forms** in Africa linked to **EBV** infection. *Acute lymphoblastic leukemia* - Typically presents with **bone marrow infiltration**, leading to symptoms like **anemia**, **thrombocytopenia**, and **leukopenia**, rather than a localized mass. - Histological findings would show **lymphoblasts** but not a 'starry sky' pattern. *Hodgkin lymphoma* - Generally presents with **painless lymphadenopathy** rather than a **rapidly growing jaw mass**, and involves **Reed-Sternberg cells** on histology. - The classic presentation does not include the characteristic 'starry sky' appearance associated with Burkitt lymphoma. *Diffuse large B-cell lymphoma* - Often presents as a **mass** but is more typically seen in older adults and does not have the **'starry sky' appearance** associated with Burkitt lymphoma. - Histologically, it would show **large B-cells** and is less aggressive in its clinical presentation compared to Burkitt lymphoma. **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. 605-606. [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. 606.

Q: In the calculation of Mean Corpuscular Volume (MCV), which formula is correct?

(Hematocrit × 10) / RBC count. **Correct: (Hematocrit × 10) / RBC count** - This formula correctly calculates the **Mean Corpuscular Volume (MCV)**, representing the average volume of red blood cells. - The multiplication by **10** is included to adjust units, typically with hematocrit in percentage and RBC count in millions/µL, to yield MCV in femtoliters (fL). - Normal MCV range: 80-100 fL *Incorrect: (Hematocrit × 100) / RBC count* - This formula is incorrect because multiplying the hematocrit by **100** instead of 10 would lead to an excessively large and inaccurate MCV value (10 times higher than actual). - The standard unit conversion requires a factor of **10** to correctly express MCV in femtoliters. *Incorrect: (Hematocrit × 10) / Total blood volume* - This formula is incorrect as **total blood volume** is not a component used in the direct calculation of Mean Corpuscular Volume. - MCV is derived from the hematocrit and RBC count, reflecting the average size of individual red blood cells. *Incorrect: (Hemoglobin × 10) / Hematocrit* - This formula is incorrect for calculating MCV; it actually represents the formula for **Mean Corpuscular Hemoglobin Concentration (MCHC)**, which measures the average concentration of hemoglobin in red blood cells. - MCV specifically measures the **average volume** of red blood cells, not their hemoglobin content or concentration.

Q: Which condition is most commonly associated with the presence of Reed-Sternberg cells in a lymph node biopsy?

Hodgkin's lymphoma. ***Hodgkin's lymphoma*** - The presence of **Reed-Sternberg cells** is a hallmark feature of Hodgkin's lymphoma, indicating **malignancy of lymphoid tissue** [1]. - These giant cells are often associated with **lymph node enlargement** and may present with **B symptoms** (fever, weight loss, night sweats) [1]. *Non-Hodgkin's lymphoma* - Does not typically show **Reed-Sternberg cells**, instead featuring a variety of **cell types** depending on the specific subtype. - Associated with **larger, often multiple lymphoid nodes**, but lacks the distinctive cell morphology seen in Hodgkin's lymphoma. *Multiple myeloma* - Characterized by the proliferation of **monoclonal plasma cells** in the bone marrow, not Reed-Sternberg cells. - Patients may exhibit **bone pain**, **anemia**, and **renal problems**, which are unrelated to Reed-Sternberg presence. *Leukemia* - Primarily involves the **bone marrow** and **blood**, not lymph nodes, and does not feature Reed-Sternberg cells. - Symptoms are more related to **cytopenias** and the **overproduction of abnormal leukocytes** rather than lymphadenopathy. **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. 614-618.

Q: A 30-year-old male presents with fatigue and easy bruising. A peripheral blood smear shows blasts with Auer rods. Which cytogenetic abnormality is most likely associated with his condition?

t(15;17). ***t(15;17)*** - The presence of **Auer rods** in blasts strongly suggests **Acute Myeloid Leukemia (AML)**, specifically the **M3 subtype** (Acute Promyelocytic Leukemia or APL) [1]. - **APL** is classically associated with the **t(15;17) translocation**, which involves the **PML** and **RARA** genes [1]. *t(8;21)* - This translocation is associated with another subtype of **AML**, specifically **AML with maturation** (M2), but it is not typically linked to the prominent presence of **Auer rods** like APL [1]. - While it is a recurrent cytogenetic abnormality in AML, it does not fit the classic presentation as well as t(15;17). *inv(16)* - The **inv(16)** (or t(16;16)) abnormality is characteristic of **AML with eosinophilia** (M4eo), a different subtype of AML [1]. - While it can be associated with some myeloid differentiation, it's not the primary association with abundant **Auer rods** and the classic APL picture [1]. *t(9;22)* - This translocation, also known as the **Philadelphia chromosome**, is primarily associated with **Chronic Myeloid Leukemia (CML)**. - Although it can also be found in some cases of acute lymphoblastic leukemia (ALL) and rarely in AML, it is not consistently associated with the presence of **Auer rods** and is not the most likely diagnosis in this clinical context. **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. 620-622.

Question 1

Direct Coombs test is positive in all EXCEPT:

Accepted Answer

G6PD deficiency

Answer

Rh incompatibility

Answer

Autoimmune hemolysis

Answer

ABO incompatibility

Question 2

Which is TRUE about JAK2 V617F mutation?

Accepted Answer

Seen in PV, ET, and PMF but rare in CML.

Answer

Seen in ET.

Answer

Rare in CML.

Answer

Common in PV but not specific.

Question 3

What is the primary site of involvement in multiple myeloma?

Accepted Answer

Bone marrow

Answer

Lungs

Answer

Liver

Answer

Spleen

Question 4

Which of the following statements about sickle cell disease is true?

Accepted Answer

Autosomal recessive

Answer

Sickled cells are flexible

Answer

Vaso-occlusion is rare

Answer

Chronic hemolysis does not occur

Question 5

Which protein is a key marker of Reed-Sternberg cells in Hodgkin's lymphoma?

Accepted Answer

CD15

Answer

CD19

Answer

CD20

Answer

CD45

Question 6

A 50-year-old male presents with fatigue and generalized lymphadenopathy. A lymph node biopsy reveals a starry sky pattern. What is the most likely diagnosis?

Accepted Answer

Burkitt lymphoma

Answer

Hodgkin lymphoma

Answer

Diffuse large B-cell lymphoma

Answer

Follicular lymphoma

Question 7

A 6-year-old boy presents with a rapidly enlarging jaw mass. Histology reveals a 'starry sky' appearance. What is the most likely diagnosis?

Accepted Answer

Burkitt lymphoma

Answer

Hodgkin lymphoma

Answer

Diffuse large B-cell lymphoma

Answer

Acute lymphoblastic leukemia

Question 8

In the calculation of Mean Corpuscular Volume (MCV), which formula is correct?

Accepted Answer

(Hematocrit × 10) / RBC count

Answer

(Hemoglobin × 10) / Hematocrit

Answer

(Hematocrit × 100) / RBC count

Answer

(Hematocrit × 10) / Total blood volume

Question 9

Which condition is most commonly associated with the presence of Reed-Sternberg cells in a lymph node biopsy?

Accepted Answer

Hodgkin's lymphoma

Answer

Non-Hodgkin's lymphoma

Answer

Multiple myeloma

Answer

Leukemia

Question 10

A 30-year-old male presents with fatigue and easy bruising. A peripheral blood smear shows blasts with Auer rods. Which cytogenetic abnormality is most likely associated with his condition?

Accepted Answer

t(15;17)

Answer

t(8;21)

Answer

inv(16)

Answer

t(9;22)

Hematopathology — MCQs

Hematopathology — MCQs

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