Hematopathology Practice Questions

Q: Which of the following is NOT true about histiocytosis X?

Associated with angiomyolipoma of the kidney. **Explanation:** **Histiocytosis X**, now more commonly known as **Langerhans Cell Histiocytosis (LCH)**, is a clonal proliferation of Langerhans cells [1]. **Why Option D is the correct answer:** Langerhans Cell Histiocytosis is **not** associated with renal angiomyolipoma. Angiomyolipoma of the kidney is a classic feature of **Tuberous Sclerosis**, a neurocutaneous syndrome [2]. LCH, while multisystemic, primarily involves the bone, skin, and lungs, but does not typically manifest with renal hamartomas [2]. **Analysis of Incorrect Options:** * **Option A:** Seborrheic-like dermatitis (scaly, erythematous rash) is a classic cutaneous presentation of LCH, particularly in the Letterer-Siwe disease variant seen in infants. * **Option B:** **Birbeck granules** are the pathognomonic ultrastructural hallmark of LCH [1]. Seen on electron microscopy, they are "tennis-racket" shaped pentalaminar structures containing the protein **Langerin (CD207)** [1]. * **Option C:** Lytic "punched-out" bony lesions (especially in the skull) are the most common clinical presentation, particularly in the Eosinophilic Granuloma variant. **High-Yield Clinical Pearls for NEET-PG:** * **Immunophenotype:** LCH cells are positive for **S100, CD1a, and Langerin (CD207)** [1]. * **Hand-Schüller-Christian Disease:** A clinical triad of LCH consisting of: 1. Lytic skull lesions, 2. Exophthalmos, and 3. Diabetes Insipidus. * **Morphology:** Cells have characteristic "coffee-bean" nuclei (grooved nuclei) [1]. * **Prognosis:** Letterer-Siwe (Multisystem) has the worst prognosis; Eosinophilic Granuloma (Unifocal) has the best. **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. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1318-1319.

Q: Atypical lymphocytes in infectious mononucleosis are primarily composed of which cell type?

CD8+ T cells. Infectious Mononucleosis (IM), typically caused by the **Epstein-Barr Virus (EBV)**, is characterized by the presence of **atypical lymphocytes** (also known as **Downey cells**) in the peripheral blood smear. **Why CD8+ T cells are correct:** EBV primarily infects B cells by binding to the **CD21 receptor** (CR2). In response to this B-cell infection, the body mounts a robust cell-mediated immune response. The "atypical lymphocytes" seen on a blood film are not the infected B cells themselves, but rather **reactive, activated CD8+ Cytotoxic T cells** that are proliferating to eliminate the EBV-infected B cells [1]. These cells are characteristically large with abundant pale blue cytoplasm that "hugs" or indents around adjacent red blood cells [1]. **Why other options are incorrect:** * **CD4+ T cells:** While involved in the overall immune coordination, they do not form the bulk of the atypical lymphocytic population in IM. * **Plasma cells:** These are terminal B-cell derivatives. While polyclonal B-cell activation occurs in IM (leading to heterophile antibodies), they do not constitute the "atypical lymphocytes." * **NK cells:** Although they participate in the innate response against viral infections, they are not the primary cell type identified as Downey cells. **High-Yield NEET-PG Pearls:** * **Triad of IM:** Fever, Pharyngitis, and Lymphadenopathy (posterior cervical) [1]. * **Diagnosis:** **Monospot test** (detects heterophile antibodies) is the screening test of choice. * **Paul-Bunnell Test:** Specific heterophile antibody test using sheep RBCs. * **Complication:** Avoid Ampicillin/Amoxicillin as it can cause a characteristic **maculopapular rash**. * **Splenic Rupture:** Patients should avoid contact sports for 3–4 weeks due to the risk of rupture from splenomegaly. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 369-370.

Question 1

Coagulation defects associated with increased coagulation are seen in which of the following conditions?

Accepted Answer

Protein C resistance

Answer

Increased Protein C

Answer

Increased Protein B

Answer

Increased Anti-thrombin HE

Question 2

Which of the following is NOT true about histiocytosis X?

Accepted Answer

Associated with angiomyolipoma of the kidney

Answer

Seborrheic dermatitis is a known feature

Answer

Birbeck's granules are a characteristic feature

Answer

Lytic bony lesions are known

Question 3

Differential white blood cell counts in the laboratory are useful in the diagnosis of which of the following conditions?

Accepted Answer

Eosinophilia

Answer

Anemia

Answer

Spherocytosis

Answer

Thrombocytopenic purpura

Question 4

Which of the following haemoglobin estimations will be diagnostically helpful in a case of beta thalassemia trait?

Accepted Answer

Hb-A2

Answer

Hb-F

Answer

Hb-C

Answer

Hb-H

Question 5

Pancytopenia with cellular bone marrow is seen in all EXCEPT?

Accepted Answer

Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency

Answer

Megaloblastic Anemia

Answer

Myelodysplastic Syndrome (MDS)

Answer

Paroxysmal Nocturnal Hemoglobinuria (PNH)

Question 6

The pathogenesis of hypochromic anemia in lead poisoning is due to which of the following mechanisms?

Accepted Answer

Inhibition of enzymes involved in heme biosynthesis

Answer

Lead blocks transferrin receptors of erythroid precursors

Answer

Lead binds to transferrin, inhibiting the transport of iron

Answer

Inhibition of the breakdown of ferritin into hemosiderin

Question 7

Which of the following agents is a prerequisite for Prothrombin time (PT) assay?

Accepted Answer

Tissue thromboplastin

Answer

Kaolin

Answer

Glass beads

Answer

Silica

Question 8

Atypical lymphocytes in infectious mononucleosis are primarily composed of which cell type?

Accepted Answer

CD8+ T cells

Answer

CD4+ T cells

Answer

Plasma cells

Answer

NK cells

Question 9

Which of the following is NOT a congenital cause of hypercoagulable states?

Accepted Answer

Antithrombin III deficiency

Answer

Protein C deficiency

Answer

Protein S deficiency

Answer

MTHFR mutation

Question 10

A 65-year-old man presents with anemia, splenomegaly, and extramedullary hematopoiesis. He reports easy fatigability, weight loss, and weakness. A bone marrow biopsy reveals marked proliferation of fibrous tissue (myelofibrosis). Which of the following is a characteristic finding in this disorder?

Accepted Answer

Teardrop-shaped erythrocytes

Answer

Depletion of bone marrow megakaryocytes

Answer

Autosplenectomy

Answer

Neoplastic plasma cells in the bone marrow

Hematopathology — MCQs

Hematopathology — MCQs

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