Hematopathology Practice Questions

Q: A 3-year-old female child presented with skin papules. Which of the following is a marker of Langerhans cell histiocytosis?

CD 1a. **Explanation:** Langerhans Cell Histiocytosis (LCH) is a clonal proliferation of Langerhans cells, which are specialized dendritic cells [1]. In children, it often presents with seborrheic-like skin rashes (papules), lytic bone lesions, or multi-organ involvement. **Why CD1a is correct:** Langerhans cells are characterized by the expression of specific surface markers and the presence of Birbeck granules (tennis-racket shaped organelles) on electron microscopy [1]. **CD1a** and **Langerin (CD207)** are the most specific immunohistochemical markers used to confirm a diagnosis of LCH. CD1a is a major histocompatibility complex (MHC) class I-like molecule involved in lipid antigen presentation. **Analysis of Incorrect Options:** * **CD3:** This is a definitive marker for **T-lymphocytes**. While T-cells may be present in the inflammatory background of LCH lesions, they are not the neoplastic cells. * **CD68:** This is a marker for **macrophages/monocytes**. While LCH cells may show weak positivity for CD68, it is non-specific and found in various other histiocytic disorders (like Sinus Histiocytosis). * **CD57:** This is a marker for **Natural Killer (NK) cells** and certain neuroendocrine tissues; it has no diagnostic role in LCH. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Marker:** Langerin (CD207) is more specific than CD1a because it correlates directly with the presence of Birbeck granules [1]. * **S100:** LCH cells are also characteristically **S100 positive** (though non-specific). * **Electron Microscopy:** Look for **Birbeck Granules** (pentalaminar, rod-shaped structures with a bulbous end) [1]. * **Genetics:** Over 50% of LCH cases harbor the **BRAF V600E mutation**, which is a frequent target in recent exam questions [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. 629-630.

Q: The parents of an 8-year-old boy complained of frequent severe bleeding on minor trauma. When they consulted a dentist for a decayed tooth, the dentist advised checking of prothrombin time (PT) and activated partial thromboplastin time (aPTT). What would be the expected results for PT and aPTT?

PT is normal, aPTT is prolonged. **Explanation:** The clinical presentation of an 8-year-old boy with frequent severe bleeding following minor trauma is highly suggestive of a hereditary coagulation disorder, most commonly **Hemophilia A (Factor VIII deficiency)** or **Hemophilia B (Factor IX deficiency)**. **1. Why Option C is Correct:** Coagulation is divided into the intrinsic, extrinsic, and common pathways. * **aPTT (Activated Partial Thromboplastin Time)** measures the **intrinsic** (Factors XII, XI, IX, VIII) and **common** pathways. Since Hemophilia involves deficiencies in Factor VIII or IX, the aPTT will be **prolonged**. * **PT (Prothrombin Time)** measures the **extrinsic** (Factor VII) and **common** pathways. Because Factor VII levels are normal in Hemophilia, the PT remains **normal**. **2. Why Other Options are Incorrect:** * **Option A:** Normal PT and aPTT are seen in platelet function disorders (like Glanzmann thrombasthenia) or Factor XIII deficiency, but not in classic hemophilia. * **Option B:** Both prolonged indicates a defect in the **common pathway** (Factors X, V, II, or Fibrinogen) or multiple deficiencies (e.g., Vitamin K deficiency, severe liver disease, or DIC). * **Option D:** Prolonged PT with normal aPTT is characteristic of an isolated **Factor VII deficiency**. **3. NEET-PG High-Yield Pearls:** * **Mixing Study:** If aPTT is prolonged, a mixing study is done. If it corrects, it indicates a **factor deficiency**; if it doesn't, it indicates an **inhibitor** (e.g., Lupus anticoagulant). * **Bleeding Time (BT):** Measures platelet function. It is **normal** in Hemophilia but prolonged in von Willebrand Disease (vWD). * **vWD:** This is the most common inherited bleeding disorder. It typically presents with prolonged aPTT (due to low Factor VIII) and prolonged BT. * **Hemophilia Inheritance:** X-linked recessive (mostly affects males).

Q: All of the following statements about Hairy cell leukaemia are true except?

Results from an expansion of neoplastic T lymphocytes. **Explanation:** **Hairy Cell Leukemia (HCL)** is a rare, chronic B-cell lymphoproliferative disorder. The correct answer is **B** because HCL is a neoplasm of **mature B-lymphocytes**, not T-lymphocytes [1]. 1. **Why Option B is the answer:** The "hairy cells" are derived from post-germinal center memory B-cells. They typically express pan-B-cell markers (CD19, CD20, CD22) and specific markers like CD11c, CD25, CD103, and Annexin A1. 2. **Why Option A is incorrect:** Splenomegaly is a hallmark of HCL and is often "conspicuous" or massive [1]. It occurs due to the infiltration of the red pulp by leukemic cells, leading to a "beefy red" appearance of the spleen [1]. Notably, lymphadenopathy is usually absent. 3. **Why Option C is incorrect:** Historically, the **TRAP (Tartrate-Resistant Acid Phosphatase)** stain was the gold standard for diagnosis. Hairy cells contain an isoenzyme of acid phosphatase that is not inhibited by tartrate. 4. **Why Option D is incorrect:** CD25 (the IL-2 receptor alpha chain) is a highly consistent and sensitive marker for HCL, used in flow cytometry to differentiate it from other B-cell lymphomas. **High-Yield Clinical Pearls for NEET-PG:** * **BRAF V600E Mutation:** Present in nearly 100% of classic HCL cases (Diagnostic). * **Dry Tap:** Bone marrow aspiration often results in a "dry tap" due to extensive **reticulin fibrosis** induced by the tumor cells [1]. * **Fried Egg Appearance:** Seen on bone marrow biopsy (cells have abundant cytoplasm and distinct borders). * **Monocytopenia:** A characteristic hematological finding. * **Treatment:** Highly sensitive to Purine analogs like **Cladribine** (2-CdA). **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. 612.

Question 1

A 3-year-old female child presented with skin papules. Which of the following is a marker of Langerhans cell histiocytosis?

Accepted Answer

CD 1a

Answer

CD 3

Answer

CD 68

Answer

CD 57

Question 2

What is the most common leukemia seen in individuals with Down syndrome?

Accepted Answer

Acute Lymphoblastic Leukemia (ALL)

Answer

Acute Myeloid Leukemia (AML)

Answer

Chronic Lymphocytic Leukemia (CLL)

Answer

Chronic Myeloid Leukemia (CML)

Question 3

A 30-year-old male develops tachycardia, hypotension (BP 70/40 mm Hg), and hematuria within 10 minutes of starting a blood transfusion in the OT. What is the most probable cause?

Accepted Answer

ABO incompatibility

Answer

Anesthetic drug hypersensitivity

Answer

Disseminated Intravascular Coagulation (DIC)

Answer

Graft-versus-Host Disease (GVHD)

Question 4

The parents of an 8-year-old boy complained of frequent severe bleeding on minor trauma. When they consulted a dentist for a decayed tooth, the dentist advised checking of prothrombin time (PT) and activated partial thromboplastin time (aPTT). What would be the expected results for PT and aPTT?

Accepted Answer

PT is normal, aPTT is prolonged

Answer

PT is normal, aPTT is normal

Answer

PT is prolonged, aPTT is prolonged

Answer

PT is prolonged, aPTT is normal

Question 5

Birbeck granules in the cytoplasm are seen in which of the following cell types?

Accepted Answer

Langerhans cells

Answer

Mast cells

Answer

Myelocytes

Answer

Thrombocytes

Question 6

A 25-year-old female presented with painless cervical lymphadenopathy for 2 months. On examination, the lymph nodes were firm in consistency. Epitrochlear lymph nodes were also involved. There was also a history of fever, night sweats, and significant weight loss. A lymph node biopsy was conducted for histopathological examination and flow cytometry studies. Which of the following genes is involved in this condition?

Accepted Answer

Bcl-2

Answer

Bcl-1

Answer

Bcl-6

Answer

Bcl-4

Question 7

Extranodal marginal zone lymphomas of MALT type can involve the thymus in the setting of which of the following conditions?

Accepted Answer

Sjogren's syndrome

Answer

HIV

Answer

Systemic Lupus Erythematosus (SLE)

Answer

Crohn's disease

Question 8

Haemoglobinuria does not occur in:

Accepted Answer

Copper sulfate poisoning

Answer

Snake bite

Answer

Mismatched blood transfusion

Answer

Thalassemia

Question 9

All of the following statements about Hairy cell leukaemia are true except?

Accepted Answer

Results from an expansion of neoplastic T lymphocytes

Answer

Splenomegaly is conspicuous

Answer

Cells are positive for Tartarate Resistant Acid phosphatase

Answer

The cells express CD25 consistently

Question 10

Isolated prolongation of the activated partial thromboplastin time (aPTT) is typically seen in which of the following conditions?

Accepted Answer

Antiphospholipid antibodies

Answer

Von Willebrand's disease

Answer

Factor VII deficiency

Answer

Vitamin K deficiency

Hematopathology — MCQs

Hematopathology — MCQs

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