Hematopathology Practice Questions

Q: Which of the following is NOT a classical feature of primary myelofibrosis?

Biconcave RBCs. **Explanation:** Primary Myelofibrosis (PMF) is a chronic myeloproliferative neoplasm characterized by clonal proliferation of megakaryocytes and granulocytes, leading to reactive bone marrow fibrosis [1]. **Why "Biconcave RBCs" is the correct answer:** Normal, healthy red blood cells are biconcave discs. In PMF, the bone marrow is replaced by dense collagen (fibrosis). As RBCs attempt to squeeze through the narrowed, fibrotic marrow spaces and the distorted vasculature of the spleen (extramedullary hematopoiesis), they undergo mechanical trauma. This results in the formation of **Dacrocytes (Tear-drop RBCs)**, not the maintenance of normal biconcave morphology [1]. **Analysis of Incorrect Options:** * **Tear drop RBCs (Dacrocytes):** These are the hallmark peripheral smear finding in PMF [1]. They occur due to the "stretching" of RBCs as they exit the fibrotic marrow. * **Leucoerythroblastosis:** This refers to the presence of immature white cells (myelocytes, metamyelocytes) and nucleated red cells in the peripheral blood [1]. It occurs because the fibrotic marrow cannot hold onto developing cells, and extramedullary sites (liver/spleen) lack the "blood-marrow barrier." * **Abnormal Megakaryocytes:** PMF is characterized by "cloud-like" or "balloon-like" clusters of atypical megakaryocytes with bulbous, hyperchromatic nuclei. **High-Yield Clinical Pearls for NEET-PG:** * **Mutation:** JAK2 V617F (approx. 50%), CALR, or MPL mutations. * **Clinical Sign:** Massive splenomegaly (due to extramedullary hematopoiesis) [1]. * **Bone Marrow:** Often results in a **"Dry Tap"** on aspiration; diagnosis requires a trephine biopsy showing silver-stained reticulin fibers. * **Laboratory:** Increased serum uric acid and LDH are common. **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. 628-629.

Q: Which of the following is true for von Willebrand disease?

Normal prothrombin time. Von Willebrand Disease (vWD) is the most common inherited bleeding disorder, characterized by a deficiency or dysfunction of von Willebrand Factor (vWF) [2]. vWF has two primary roles: mediating platelet adhesion to subendothelial collagen (primary hemostasis) and acting as a carrier protein to stabilize Factor VIII (secondary hemostasis) [2]. **Why Option C is correct:** The **Prothrombin Time (PT)** measures the extrinsic and common pathways (Factors VII, X, V, II, and I) [3]. Since vWD only affects vWF and potentially Factor VIII (intrinsic pathway), the PT remains **normal** [3]. **Why other options are incorrect:** * **A. Normal PTT:** This is incorrect because vWF stabilizes Factor VIII. In many cases of vWD (especially Type 1 and 2N), Factor VIII levels are low, leading to a **prolonged Activated Partial Thromboplastin Time (aPTT)** [2]. * **B. Decreased platelets:** Platelet count is typically **normal** in most types of vWD [2]. The exception is Type 2B vWD (gain-of-function mutation), where increased binding to platelets leads to mild thrombocytopenia, but this is not the general rule. * **D. Normal bleeding time:** Bleeding time (BT) measures primary hemostasis. Since vWF is essential for platelet-vessel wall adhesion, the **BT is characteristically prolonged**. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Most types are Autosomal Dominant (Type 3 is Autosomal Recessive) [2]. * **Screening Tests:** Prolonged BT, normal/prolonged aPTT, and normal PT/Platelet count [2], [3]. * **Confirmatory Test:** Ristocetin Cofactor Assay (measures vWF activity) [2]. * **Treatment:** **Desmopressin (DDAVP)** is the drug of choice for Type 1 as it releases stored vWF from Weibel-Palade bodies [1], [2]. For Type 3 or severe cases, vWF-containing concentrates are used [2].

Q: A 50-year-old patient presents with fever, bleeding episodes, and a leukocyte count of 48 x 10^9 cells/L and platelet count of 50 x 10^9 cells/L. The differential count showed 76% neutrophils, 8% blast cells, 12% myelocytes and metamyelocytes, and 4% other cells. Bone marrow examination showed 14% blasts. Cytogenetics showed t(8;21). What is the most likely diagnosis?

Acute myeloid leukemia. ### Explanation The correct diagnosis is **Acute Myeloid Leukemia (AML)**. **1. Why the correct answer is right:** According to the **WHO classification of myeloid neoplasms**, the standard threshold for diagnosing AML is a blast count of **≥20%** in the blood or bone marrow. However, there is a critical exception: the presence of specific recurrent genetic abnormalities—namely **t(8;21)**, **inv(16)**, or **t(15;17)**—defines AML **regardless of the blast percentage** [1]. In this case, although the blasts are only 8% in the peripheral blood and 14% in the marrow, the cytogenetic finding of **t(8;21)** (which involves the *RUNX1-RUNX1T1* fusion) is pathognomonic for AML (specifically AML-M2 in the FAB classification) [1]. **2. Why the incorrect options are wrong:** * **Chronic Myeloid Leukemia (CML):** While CML presents with a high leukocyte count and a **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. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 613-614.

Q: Pseudothrombocytopenia is due to platelet agglutination antibodies when the calcium content is decreased by blood EDTA. The antibody responsible for this effect is mainly:

IgG. **Explanation:** **Pseudothrombocytopenia (PTCP)** is an *in vitro* laboratory artifact where the automated platelet count is falsely low. This occurs due to platelet clumping (agglutination) in blood samples collected in **EDTA-anticoagulated tubes**. **1. Why IgG is the correct answer:** The phenomenon is mediated by **naturally occurring autoantibodies**, which are almost always of the **IgG class** (though IgM is rarely implicated). These antibodies are "cryptic," meaning they only recognize and bind to the **GP IIb/IIIa receptor** on the platelet surface when its conformation is altered. EDTA acts as a chelating agent that decreases ionized calcium; this reduction in calcium causes a structural change in the GP IIb/IIIa complex, exposing the hidden epitopes. The IgG antibodies then bind to these sites, causing platelets to agglutinate, which the automated counter misidentifies as single large particles or leukocytes. **2. Why other options are incorrect:** * **IgA and IgD:** These immunoglobulins are not associated with the cold-reacting autoantibody mechanism involved in EDTA-induced clumping. * **IgM:** While IgM can occasionally be involved in cold agglutinin diseases, the specific EDTA-dependent mechanism that targets the GP IIb/IIIa complex is predominantly mediated by IgG. **Clinical Pearls for NEET-PG:** * **Diagnosis:** Suspect PTCP if the patient has a low platelet count but **no clinical signs of bleeding** (petechiae/purpura). * **Confirmation:** Examine a **peripheral blood smear** to visualize platelet clumps. * **Management:** Repeat the test using a different anticoagulant, such as **Sodium Citrate (blue top)** or Heparin, or perform a manual count immediately after collection. * **Key Association:** It is a purely *in vitro* phenomenon with no clinical significance for the patient's actual hemostatic status.

Q: Which of the following statements regarding G6PD deficiency is true?

It is associated with bite cells.. **Explanation:** **Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency** is the most common red cell enzyme defect worldwide. It results in an inability to maintain adequate levels of reduced glutathione, leaving hemoglobin vulnerable to oxidative stress. **1. Why Option B is correct:** When RBCs are exposed to oxidative stress (e.g., fava beans, infections, or drugs like Primaquine), hemoglobin denatures and precipitates into **Heinz bodies**. As these cells pass through the splenic sinusoids, splenic macrophages "pluck out" these inclusions. This process removes a portion of the red cell membrane, resulting in characteristic **"Bite cells" (Degmacytes)**. If the cell remains in circulation, it may appear as a **Blister cell**. **2. Why other options are incorrect:** * **Option A:** G6PD deficiency is an **X-linked recessive** condition, primarily affecting males. * **Option C:** It provides a survival advantage against **Malaria** (*Plasmodium falciparum*), not Kala-azar. The oxidative stress inhibits the optimal growth of the parasite within the RBC. * **Option D:** Enzyme levels are **inversely proportional** to the age of RBCs. Reticulocytes and young RBCs have the highest enzyme activity, while older cells are most deficient. This is why G6PD levels may appear falsely normal during an acute hemolytic episode (as older cells have been destroyed). **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Best initial test is a peripheral smear (Bite cells); Gold standard is the **Quantitative spectrophotometric assay** (performed 6–8 weeks after a hemolytic crisis). * **Common Triggers:** Sulfa drugs, Nitrofurantoin, Primaquine, Naphthalene balls, and Fava beans. * **Inheritance:** X-linked recessive (Lyon’s hypothesis explains rare symptomatic females).

Q: A patient has normal prothrombin time (PT) and platelet count. The activated partial thromboplastin time (aPTT) is increased, and factor VIII levels are observed to be 60% (normal). There is no associated history of bleeding even after a surgical procedure. What is the most likely diagnosis?

Lupus anticoagulant. The clinical scenario describes an **isolated prolonged aPTT** with a normal PT, normal platelet count, and normal Factor VIII levels (60% is within the low-normal range). The most critical clue is the **absence of bleeding**, even after surgical stress. **1. Why Lupus Anticoagulant (LA) is correct:** Lupus anticoagulant is an antiphospholipid antibody. In *vitro* (in the lab), these antibodies interfere with the phospholipids used in the aPTT reagent, causing a paradoxical prolongation of the clotting time [1]. However, in *vivo* (in the body), LA is **pro-thrombotic**, not pro-hemorrhagic. Therefore, patients do not bleed; instead, they are at risk for arterial and venous thrombosis. This "asymptomatic prolongation of aPTT" is a classic board exam presentation for LA. **2. Why other options are incorrect:** * **Factor IX deficiency (Hemophilia B):** This would cause a prolonged aPTT, but it is characterized by a significant **bleeding tendency** (hemarthrosis, post-surgical bleeding). * **Factor VIII inhibitors:** These are antibodies against Factor VIII. They cause a prolonged aPTT and **severe bleeding** manifestations [1]. Furthermore, Factor VIII levels would be significantly low, not 60%. * **Thalassemia:** This is a hemoglobinopathy affecting red blood cells. It does not affect the coagulation cascade, PT, or aPTT. **Clinical Pearls for NEET-PG:** * **Mixing Study:** If aPTT remains prolonged after mixing the patient's plasma with normal plasma (1:1), it indicates the presence of an **inhibitor** (like LA) rather than a factor deficiency [1]. * **The "Silent" Prolonged aPTT:** Always consider **Factor XII deficiency** or **Lupus Anticoagulant** when aPTT is high but the patient has no bleeding symptoms. * **Paradox:** LA causes a "long aPTT" in the lab but "clots" in the patient.

Question 1

Which of the following is associated with an adverse prognosis in Acute Myeloid Leukemia (AML)?

Accepted Answer

Del 7q

Answer

t(8;21)

Answer

t(15;17)

Answer

Normal cytogenetics

Question 2

Which of the following is NOT a classical feature of primary myelofibrosis?

Accepted Answer

Biconcave RBCs

Answer

Tear drop RBCs

Answer

Leucoerythroblastosis

Answer

Abnormal megakaryocytes

Question 3

Which of the following is true for von Willebrand disease?

Accepted Answer

Normal prothrombin time

Answer

Normal partial thromboplastin time

Answer

Decreased platelets

Answer

Normal bleeding time

Question 4

Prothrombin time is useful for which of the following?

Accepted Answer

Evaluation of a patient taking anticoagulant drugs

Answer

Detection of clot retraction

Answer

Platelet count

Answer

Diagnosis of hemophilia

Question 5

A 50-year-old patient presents with fever, bleeding episodes, and a leukocyte count of 48 x 10^9 cells/L and platelet count of 50 x 10^9 cells/L. The differential count showed 76% neutrophils, 8% blast cells, 12% myelocytes and metamyelocytes, and 4% other cells. Bone marrow examination showed 14% blasts. Cytogenetics showed t(8;21). What is the most likely diagnosis?

Accepted Answer

Acute myeloid leukemia

Answer

Chronic myeloid leukemia

Answer

Chronic lymphoid leukemia

Answer

Myelodysplastic syndrome

Question 6

Pseudothrombocytopenia is due to platelet agglutination antibodies when the calcium content is decreased by blood EDTA. The antibody responsible for this effect is mainly:

Accepted Answer

IgG

Answer

IgA

Answer

IgM

Answer

IgD

Question 7

Which of the following statements regarding G6PD deficiency is true?

Accepted Answer

It is associated with bite cells.

Answer

It is an autosomal dominant condition.

Answer

It protects against kala azar.

Answer

Enzyme levels are directly proportional to the age of RBCs.

Question 8

Overexpression of BCL-2 proteins occurs in which of the following conditions?

Accepted Answer

Follicular lymphoma

Answer

Burkitt's lymphoma

Answer

Diffuse large B-cell lymphoma

Answer

AML

Question 9

A patient has normal prothrombin time (PT) and platelet count. The activated partial thromboplastin time (aPTT) is increased, and factor VIII levels are observed to be 60% (normal). There is no associated history of bleeding even after a surgical procedure. What is the most likely diagnosis?

Accepted Answer

Lupus anticoagulant

Answer

Factor IX deficiency

Answer

Factor VIII inhibitors

Answer

Thalassemia

Question 10

Which lymphoid malignancy arises from thymic cells?

Accepted Answer

Pre-T cell ALL

Answer

Hairy cell leukemia

Answer

Burkitt lymphoma

Answer

Pre-B cell ALL

Hematopathology — MCQs

Hematopathology — MCQs

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