Hematopathology Practice Questions

Q: Chediak Higashi syndrome is characterized by which of the following?

All the above. **Explanation:** Chediak-Higashi Syndrome (CHS) is a rare autosomal recessive disorder characterized by a defect in **intracellular protein trafficking** [1]. The underlying pathology is a mutation in the **LYST gene** (Lysosomal Trafficking Regulator), which leads to the failure of phagosome-lysosome fusion [1]. * **Giant Granules in Leukocytes:** Due to the defect in vesicle fusion, lysosomes and secretory granules fuse uncontrollably, forming pathognomonic **giant azurophilic granules** in neutrophils, eosinophils, and monocytes [1]. These are visible on a peripheral blood smear. * **Albinism:** The LYST mutation also affects melanocytes. Melanin cannot be properly distributed from melanosomes to keratinocytes, resulting in **oculocutaneous albinism** (silvery hair and light skin) [1]. * **Mutation in LYST gene:** This is the primary genetic defect located on chromosome 1q42. Since all three features are hallmark characteristics of the disease, **Option D (All the above)** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Immunodeficiency:** Patients suffer from recurrent pyogenic infections (especially *Staphylococcus aureus*) due to impaired chemotaxis and delayed microbial killing [1]. * **Neuropathy:** Progressive neurological deterioration (ataxia, tremors, and peripheral neuropathy) is common in survivors [1]. * **Bleeding Diathesis:** Caused by a deficiency in platelet dense bodies [1]. * **Accelerated Phase:** A life-threatening "hemophagocytic lymphohistiocytosis" (HLH)-like syndrome triggered by viral infections (often EBV), leading to hepatosplenomegaly and pancytopenia. * **Diagnosis:** Peripheral smear showing giant peroxidase-positive granules in neutrophils. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 245-246.

Q: In which of the following conditions can Downey cells be seen?

Infectious mononucleosis. **Explanation:** **Infectious Mononucleosis (IM)** is the classic condition associated with **Downey cells** [1]. These are **atypical T-lymphocytes** (specifically CD8+ cytotoxic T-cells) that have been activated in response to B-cells infected by the **Epstein-Barr Virus (EBV)**. Morphologically, Downey cells are larger than mature lymphocytes, featuring abundant, "balloons-out" cytoplasm that often indents or "hugs" adjacent red blood cells, and a nucleus with coarse or smudged chromatin [1]. **Analysis of Incorrect Options:** * **Small Lymphocytic Lymphoma (SLL):** Characterized by small, mature-looking lymphocytes and "Smudge cells" (fragile cells that burst during smear preparation), not atypical reactive T-cells. * **Acute Myeloid Leukemia (AML):** Defined by the presence of myeloblasts (containing Auer rods) rather than reactive lymphocytes. * **Multiple Myeloma:** A plasma cell dyscrasia characterized by malignant plasma cells in the bone marrow, often showing "Fried egg" appearance or "Mott cells," but not Downey cells. **High-Yield Clinical Pearls for NEET-PG:** * **Triad of IM:** Fever, pharyngitis, and lymphadenopathy (posterior cervical) [1]. * **Diagnosis:** Heterophile antibody test (**Monospot test**) is the screening gold standard. * **The "Indentation" Sign:** The cytoplasm of Downey cells scalloping around RBCs is a classic morphological descriptor in exams [1]. * **Complication:** Avoid contact sports due to the risk of **splenic rupture**. * **Antibiotic Caution:** Administration of Ampicillin/Amoxicillin in IM patients often results in a characteristic maculopapular rash. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 369-370.

Q: Disseminated Intravascular Coagulation (DIC) is commonly seen in which subtype of Acute Myeloid Leukemia (AML)?

M3 AML. **Explanation:** **Correct Option: C (M3 AML)** Acute Promyelocytic Leukemia (APL), classified as **FAB M3**, is the subtype most strongly associated with **Disseminated Intravascular Coagulation (DIC)** [1]. This is a medical emergency. The underlying mechanism involves the presence of numerous primary granules in the malignant promyelocytes. These granules contain **Tissue Factor-like procoagulants** and **fibrinolytic enzymes**. When these cells die (either naturally or due to chemotherapy), they release these substances into the circulation, triggering the extrinsic coagulation pathway and systemic fibrinolysis, leading to life-threatening hemorrhage and microvascular thrombosis. **Incorrect Options:** * **A (M1 AML):** AML without maturation. It lacks the significant granular content required to trigger massive DIC. * **B (M2 AML):** AML with maturation. While it is the most common subtype of AML, it is typically associated with the t(8;21) translocation and chloromas (granulocytic sarcomas), not primary DIC. * **D (M4 AML):** Acute Myelomonocytic Leukemia. This subtype (specifically M4eo) is characterized by gum hypertrophy and skin involvement due to monocytic infiltration, rather than coagulopathy. **High-Yield Clinical Pearls for NEET-PG:** * **Cytogenetics:** M3 is associated with **t(15;17)**, involving the *PML-RARα* fusion gene [1]. * **Morphology:** Look for **Auer rods** (often in bundles called **Faggot cells**) [1]. * **Treatment:** The standard of care is **All-trans Retinoic Acid (ATRA)**, which induces the maturation of promyelocytes into neutrophils, bypassing the massive release of procoagulants. * **Stain:** M3 shows strong positivity for **Myeloperoxidase (MPO)**. **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

A 24-year-old male complained of recurrent attacks of sore throat for the past 2 years. His total leukocyte count was 3000/μl. A differential count revealed severe neutropenia. What is the most likely diagnosis?

Accepted Answer

Agranulocytosis

Answer

Subleukemic leukemia

Answer

Infectious mononucleosis

Answer

Leukoerythroblastic anemia

Question 2

The expression of JAK2 mutation is seen in all conditions, EXCEPT:

Accepted Answer

Chronic eosinophilic leukemia

Answer

Primary myelofibrosis

Answer

Polycythemia vera

Answer

Essential thrombocytosis

Question 3

Reed-Sternberg cells are characteristically seen in which of the following conditions?

Accepted Answer

Hodgkin's disease

Answer

Alpha-thalassemia

Answer

Glandular fever

Answer

Hansen's disease

Question 4

Chediak Higashi syndrome is characterized by which of the following?

Accepted Answer

All the above

Answer

Giant granules in leukocytes

Answer

Albinism

Answer

Mutation in LYST gene

Question 5

All of the following are true regarding Chronic Lymphocytic Leukemia (CLL) except?

Accepted Answer

Affects T-cells

Answer

Most common type of leukemia in adults

Answer

Males are commonly affected

Answer

ZAP-70 has prognostic importance

Question 6

Microscopy of a specimen shows "pawn ball megakaryocytes". This finding is associated with which of the following conditions?

Accepted Answer

Myelodysplastic syndrome

Answer

Idiopathic thrombocytopenic purpura

Answer

Thrombotic thrombocytopenic purpura

Answer

Chloramphenicol toxicity

Question 7

In which of the following conditions can Downey cells be seen?

Accepted Answer

Infectious mononucleosis

Answer

Small lymphocytic lymphoma

Answer

Acute myeloid leukemia

Answer

Multiple myeloma

Question 8

Disseminated Intravascular Coagulation (DIC) is commonly seen in which subtype of Acute Myeloid Leukemia (AML)?

Accepted Answer

M3 AML

Answer

M1 AML

Answer

M2 AML

Answer

M4 AML

Question 9

Which of the following conditions is NOT associated with increased risk of infective endocarditis?

Accepted Answer

Infective endocarditis

Answer

Sickle cell disease

Answer

Celiac disease

Answer

Thrombocythemia

Question 10

Haemophilia A and Von Willebrand's disease are coagulation disorders due to deficiency of which factor?

Accepted Answer

Factor VIII

Answer

Factor IX

Answer

Vitamin K

Answer

Factor X

Hematopathology — MCQs

Hematopathology — MCQs

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