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: 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: 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.

Question 1

All of the following acute myeloid leukemias are diagnosed regardless of blast count, except?

Accepted Answer

AML with t(1;9)

Answer

AML with t(8;21)

Answer

AML with t(15;17)

Answer

AML with t(16;16)

Question 2

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 3

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 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

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 6

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 7

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 8

Which syndrome is associated with an increased risk of leukemia?

Accepted Answer

Klinefelter syndrome

Answer

Plummer Vinson syndrome

Answer

Sturge Weber syndrome

Answer

Multiple hamartoma syndrome

Question 9

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

Question 10

All of the following are good prognostic factors for acute lymphoblastic leukemia except?

Accepted Answer

+ (9;22), + (8;14)

Answer

Age of onset between 2-8 years

Answer

Hyperdiploidy, trisomy of chromosomes 4, 7 and 10 and + (12;21)

Answer

Initial WBC count less than 50000

Hematopathology — MCQs

Hematopathology — MCQs

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