Hematopathology Practice Questions

Q: What is the characteristic shape of Birbeck granules?

Tennis racket. **Explanation:** **Birbeck granules** are the pathognomonic ultrastructural hallmark of **Langerhans Cell Histiocytosis (LCH)**. These are rod-shaped, pentalaminar cytoplasmic organelles with a central striated line and a bulbous end, giving them a classic **tennis racket** appearance under electron microscopy [1]. They are formed by the invagination of the cell membrane and are associated with the protein **Langerin (CD207)**, which is involved in antigen processing [1]. **Analysis of Options:** * **Option D (Tennis racket):** This is the correct description. The "handle" of the racket is the rod-like portion, and the "head" is the dilated vesicular end [1]. * **Option A (Hockeystick):** This is a distractor. While some granules might appear slightly curved, "tennis racket" is the standard medical descriptor. * **Option B (Bat):** Incorrect. This does not describe the specific pentalaminar structure seen on EM. * **Option C (Ball):** Incorrect. Birbeck granules are elongated rods, not spherical structures. **High-Yield Clinical Pearls for NEET-PG:** * **Cell of Origin:** Langerhans cells (dendritic cells of the skin/monocyte-macrophage lineage). * **Immunohistochemistry (IHC) Markers:** LCH cells are characteristically positive for **S-100**, **CD1a**, and **Langerin (CD207)** [1]. CD207 is the most specific marker. * **Clinical Presentation:** Can range from a solitary bone lesion (Eosinophilic Granuloma) to multisystem involvement (Letterer-Siwe disease). * **Radiology:** Often presents as "punched-out" lytic lesions in the skull. **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. 630.

Q: What type of RBC is typically seen in chronic renal failure?

Normocytic. **Explanation:** The hallmark of anemia in Chronic Renal Failure (CRF) is a **Normocytic Normochromic Anemia**. **Why Normocytic is Correct:** The primary cause of anemia in CRF is the **deficiency of Erythropoietin (EPO)** [2]. EPO is a glycoprotein hormone produced by the peritubular interstitial cells of the kidney [2], [3]. As renal parenchyma is lost, EPO production decreases, leading to reduced stimulation of the bone marrow to produce red blood cells [2]. Since the defect lies in the *quantity* of cells produced rather than the *quality* of hemoglobin synthesis or cell division, the resulting RBCs are normal in size (normocytic) and color (normochromic). **Why other options are incorrect:** * **Microcytic:** This is typically seen in Iron Deficiency Anemia (IDA). While CRF patients may develop IDA due to chronic blood loss (hemodialysis or GI bleeds) or functional iron deficiency (hepcidin-mediated), the classic, primary presentation of renal anemia remains normocytic [1]. * **Macrocytic:** This is characteristic of Vitamin B12 or Folate deficiency. While malnutrition can occur in uremic patients, it is not the standard hematological profile of renal failure itself. **High-Yield Clinical Pearls for NEET-PG:** * **Target Hemoglobin:** In patients on EPO therapy for CRF, the target Hb is usually **10–11.5 g/dL**. Aiming for normal levels (>13 g/dL) increases the risk of stroke and cardiovascular events (CHOIR and CREATE trials). * **Burr Cells (Echinocytes):** These are small, spiked RBCs often seen on the peripheral smear of uremic patients. * **Resistance to EPO:** The most common cause of a poor response to exogenous EPO in CRF patients is **Iron Deficiency** [1]. Always check ferritin and TSAT levels before starting EPO.

Q: A 13-year-old female attends a hematology clinic for follow-up of a coagulation defect in the extrinsic pathway. Which coagulation factor is defective?

VII. **Explanation:** The coagulation cascade is traditionally divided into the intrinsic, extrinsic, and common pathways. To answer this question, one must identify which factor is unique to the **extrinsic pathway**. 1. **Why Factor VII is correct:** Factor VII is the only factor involved exclusively in the extrinsic pathway [2]. This pathway is initiated when subendothelial **Tissue Factor (Factor III)** is exposed to circulating Factor VII following vascular injury. The resulting TF-VIIa complex then activates Factor X (the start of the common pathway). In clinical practice, a defect in the extrinsic pathway is characterized by an isolated prolongation of **Prothrombin Time (PT)**, while the Activated Partial Hypotension Time (aPTT) remains normal. 2. **Why the other options are incorrect:** * **Factors VIII, IX, and XI** are all components of the **intrinsic pathway**. * Deficiencies in these factors (e.g., Hemophilia A [VIII], Hemophilia B [IX], or Hemophilia C [XI]) result in a prolonged **aPTT**, while the PT remains normal [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for PT/Extrinsic:** "PET" (PT, Extrinsic, Tissue Factor/Factor VII). * **Mnemonic for aPTT/Intrinsic:** "PITT" (PTT, Intrinsic, Twelve, Eleven, Ten, Nine, Eight—though note Factor X is common). * **Factor VII** has the **shortest half-life** (approx. 4–6 hours) among all clotting factors [1]. Therefore, PT is the first lab value to become deranged in acute liver failure or early Warfarin therapy. * **Vitamin K-dependent factors:** II, VII, IX, and X (Factor VII is the most sensitive to Vitamin K deficiency) [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 582-583. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 128-130.

Question 1

Examination of a peripheral blood smear demonstrates a leukemia composed of small mature lymphocytes without blast forms. Which of the following is the most likely age of this patient?

Accepted Answer

65 years

Answer

1 year

Answer

45 years

Answer

5 years

Question 2

Golf ball inclusion bodies in RBCs are seen in which condition?

Accepted Answer

HbH disease

Answer

Normal reticulocytes

Answer

Pernicious anaemia

Answer

G6PD deficiency

Question 3

D-Dimer values may be increased in all of the following conditions except?

Accepted Answer

Anticoagulant therapy

Answer

Myocardial infarction

Answer

Pneumonia

Answer

Pregnancy

Question 4

What is the characteristic shape of Birbeck granules?

Accepted Answer

Tennis racket

Answer

Hockeystick

Answer

Bat

Answer

Ball

Question 5

What type of RBC is typically seen in chronic renal failure?

Accepted Answer

Normocytic

Answer

Microcytic

Answer

Macrocytic

Answer

None of the above

Question 6

Maturation defect of RBCs is seen in which of the following conditions?

Accepted Answer

Vitamin B12 deficiency

Answer

Vitamin B6 deficiency

Answer

Iron deficiency

Answer

Protein deficiency

Question 7

A 13-year-old female attends a hematology clinic for follow-up of a coagulation defect in the extrinsic pathway. Which coagulation factor is defective?

Accepted Answer

VII

Answer

VIII

Answer

IX

Answer

XI

Question 8

Multiple myeloma is diagnosed by which of the following criteria?

Accepted Answer

Greater than 10% plasmacytosis

Answer

24-hour urine protein measurement

Answer

Kidney biopsy

Answer

Rouleaux formation in peripheral blood smear

Question 9

Ham's test is used in the screening of which of the following conditions?

Accepted Answer

Paroxysmal nocturnal hemoglobinuria

Answer

Hereditary spherocytosis

Answer

G6PD deficiency

Answer

Any hemolytic disorder

Question 10

Massive splenomegaly is defined if the spleen weighs greater than:

Accepted Answer

1 kg

Answer

500 grams

Answer

1.5 kg

Answer

2 kg

Hematopathology — MCQs

Hematopathology — MCQs

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