Hematopathology — MCQs
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A 22-year-old male presents with fatigue, recurrent fever, and enlarged cervical lymph nodes. Peripheral blood smear shows numerous atypical lymphocytes. A biopsy of an enlarged lymph node reveals expansion of lymphoid follicles with preserved underlying architecture, and numerous atypical lymphocytes in the paracortical areas. What is the most likely diagnosis?
Which of the following may present with isolated prolongation of prothrombin time (PT)?
Hydrops fetalis due to Hb Barts is associated with which of the following?
A 40-year-old woman complains of fatigue and nausea of 3 months in duration. Physical examination reveals numerous pustules on the face, as well as splenomegaly and hepatomegaly. Laboratory studies show hemoglobin of 6.3 g/dL and platelets of 50,000/mL. A peripheral smear shows malignant cells with Auer rods. The patient develops diffuse purpura, bleeding from the gums, and laboratory features of disseminated intravascular coagulation (DIC). Which of the following is the appropriate diagnosis?
A patient presented with fever, night sweats, and weight loss. Clinical examination revealed painless lymphadenopathy. Microscopy shows Reed Sternberg cells. What is the most likely condition?
A mother is diagnosed with sickle cell disease, and her husband is normal. What are the chances of having children with sickle cell disease and sickle cell trait, respectively?
Paroxysmal nocturnal hemoglobinuria (PNH) occurs due to a defect in which of the following?
A peripheral smear shows hypersegmented neutrophils. This finding is most likely due to a deficiency of which of the following?
Bone marrow plasmacytosis in multiple myeloma is characteristically more than:
CD-15 helps in the assessment of which of the following?
Hematopathology Indian Medical PG Practice Questions and MCQs
Question 901: A 22-year-old male presents with fatigue, recurrent fever, and enlarged cervical lymph nodes. Peripheral blood smear shows numerous atypical lymphocytes. A biopsy of an enlarged lymph node reveals expansion of lymphoid follicles with preserved underlying architecture, and numerous atypical lymphocytes in the paracortical areas. What is the most likely diagnosis?
- A. AIDS
- B. Burkitt's lymphoma
- C. Hodgkin's Disease
- D. Infectious mononucleosis (Correct Answer)
Explanation: **Explanation:** The clinical presentation of a young adult with the triad of **fever, fatigue, and lymphadenopathy**, combined with a peripheral smear showing **atypical lymphocytes** (Downey cells), is classic for **Infectious Mononucleosis (IM)**, usually caused by the Epstein-Barr Virus (EBV) [1]. **Why Option D is Correct:** In IM, the lymph node architecture is typically **preserved** but shows marked **paracortical hyperplasia** [1]. This expansion is due to the proliferation of activated T-lymphocytes (CD8+ T-cells) reacting against EBV-infected B-cells [1]. These activated T-cells appear as "atypical lymphocytes" in both the paracortex and peripheral blood [1]. **Why Other Options are Incorrect:** * **A. AIDS:** While it causes lymphadenopathy, the early stage (PGL) shows follicular hyperplasia, but the characteristic "atypical lymphocytosis" and specific paracortical expansion described are hallmarks of acute EBV infection. * **B. Burkitt’s Lymphoma:** This is a high-grade B-cell neoplasm. Histology would show a "starry-sky appearance" with complete effacement of architecture, not preserved follicles and paracortical expansion. * **C. Hodgkin’s Disease:** This would typically show Reed-Sternberg (RS) cells in a polymorphic background [2]. While it can involve the paracortex, the presence of numerous atypical lymphocytes in the peripheral blood strongly points toward a reactive process like IM rather than a malignancy. **NEET-PG High-Yield Pearls:** * **Atypical Lymphocytes (Downey Cells):** These are activated CD8+ T-cells, not B-cells [1]. They characteristically "skirt" or mold around adjacent RBCs. * **Monospot Test:** Detects heterophile antibodies (IgM) that agglutinate horse/sheep RBCs. * **Paul-Bunnell Test:** The specific tube dilution test for heterophile antibodies. * **Complication:** Avoid Ampicillin/Amoxicillin in these patients as it can trigger a characteristic maculopapular rash. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 368-370. [2] 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. 618.
Question 902: Which of the following may present with isolated prolongation of prothrombin time (PT)?
- A. Factor VIII deficiency
- B. Factor VII deficiency (Correct Answer)
- C. Factor XII deficiency
- D. Factor IX deficiency
Explanation: To understand this question, one must recall the coagulation cascade and which laboratory tests monitor specific pathways [2]. ### **1. Why Factor VII deficiency is correct** The **Prothrombin Time (PT)** measures the integrity of the **Extrinsic Pathway** and the Common Pathway [2]. **Factor VII** is the only factor unique to the extrinsic pathway. Therefore, a deficiency in Factor VII will lead to an isolated prolongation of PT, while the Activated Partial Thromboplastin Time (aPTT) remains normal. ### **2. Why the other options are incorrect** * **Factor VIII (Option A) and Factor IX (Option D):** These factors are part of the **Intrinsic Pathway**. Deficiencies in these (Hemophilia A and B, respectively) result in an isolated prolongation of **aPTT**, while the PT remains normal [1]. * **Factor XII (Option C):** This is the "Hageman factor" which initiates the intrinsic pathway *in vitro*. Deficiency leads to a markedly prolonged **aPTT** but, characteristically, does **not** cause clinical bleeding. ### **3. High-Yield Clinical Pearls for NEET-PG** * **Isolated Prolonged PT:** Think Factor VII deficiency, early Vitamin K deficiency, or early Liver disease (Factor VII has the shortest half-life) [1]. * **Isolated Prolonged aPTT:** Think Hemophilia A (VIII), B (IX), C (XI), or Von Willebrand Disease (due to low VIII levels) [1]. * **Prolonged PT + aPTT:** Think Common Pathway deficiencies (Factors X, V, II, or I), severe Vitamin K deficiency, or advanced Liver disease [1]. * **Mixing Study:** If a prolonged PT or aPTT corrects after mixing with normal plasma, it indicates a **factor deficiency**. If it does not correct, it indicates the presence of an **inhibitor** (e.g., Lupus anticoagulant). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 622-625. [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 903: Hydrops fetalis due to Hb Barts is associated with which of the following?
- A. Hb Barts cannot bind oxygen.
- B. Excess alpha-globin chains form insoluble precipitates.
- C. Hb Barts cannot release oxygen to fetal tissues. (Correct Answer)
- D. Microcytic red blood cells become trapped in the placenta.
Explanation: **Explanation:** **1. Why the Correct Answer is Right:** Hb Barts is a tetramer of four gamma chains ($\gamma_4$) that occurs in **Alpha-thalassemia major** (deletion of all four alpha-globin genes) [1]. Because alpha-globin chains are essential for all normal adult and fetal hemoglobins (HbA, HbA2, and HbF), their absence leads to the formation of $\gamma_4$ tetramers. Hb Barts has an **extremely high oxygen affinity**—approximately 10 times higher than HbA. Consequently, it binds oxygen tightly in the lungs/placenta but **fails to release it to the fetal tissues**. This results in severe tissue hypoxia, high-output heart failure, massive edema (hydrops fetalis), and intrauterine death [3]. **2. Why Incorrect Options are Wrong:** * **Option A:** Hb Barts *can* bind oxygen; in fact, it binds it too efficiently. The pathology lies in the inability to unload it. * **Option B:** This describes **Beta-thalassemia**. In Alpha-thalassemia, there is a deficiency of alpha chains, leading to an excess of gamma chains (in fetuses) or beta chains (HbH in adults) [1]. It is the excess alpha chains in Beta-thalassemia that form insoluble precipitates (Heinz bodies). * **Option D:** While the RBCs are microcytic and hypochromic, the primary cause of hydrops is tissue hypoxia and cardiac failure, not mechanical trapping in the placenta [3]. **3. Clinical Pearls for NEET-PG:** * **Hb Barts:** $\gamma_4$ (Alpha-thalassemia major/Hydrops fetalis). * **HbH:** $\beta_4$ (Three-gene deletion alpha-thalassemia); shows "golf ball" appearance on supra-vital staining [2]. * **Electrophoresis:** Hb Barts is fast-moving on alkaline electrophoresis. * **Management:** Intrauterine blood transfusions can sometimes salvage the fetus, but the prognosis remains extremely poor. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 649-650. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 600-601. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 470-472.
Question 904: A 40-year-old woman complains of fatigue and nausea of 3 months in duration. Physical examination reveals numerous pustules on the face, as well as splenomegaly and hepatomegaly. Laboratory studies show hemoglobin of 6.3 g/dL and platelets of 50,000/mL. A peripheral smear shows malignant cells with Auer rods. The patient develops diffuse purpura, bleeding from the gums, and laboratory features of disseminated intravascular coagulation (DIC). Which of the following is the appropriate diagnosis?
- A. Acute lymphoblastic leukemia
- B. Acute megakaryocytic leukemia
- C. Acute promyelocytic leukemia (Correct Answer)
- D. Chronic myelogenous leukemia
Explanation: ### Explanation **Correct Answer: C. Acute Promyelocytic Leukemia (APL)** **1. Why it is correct:** The clinical presentation is classic for **Acute Promyelocytic Leukemia (AML-M3)**. The presence of **Auer rods** in malignant cells confirms a myeloid lineage (AML) [1]. The hallmark of APL is the high risk of **Disseminated Intravascular Coagulation (DIC)**, triggered by the release of procoagulants (tissue factor-like substances) from the primary granules of the promyelocytes [2]. This explains the patient's diffuse purpura and gum bleeding. Additionally, the "pustules" mentioned are likely **Sweet Syndrome** (acute febrile neutrophilic dermatosis) or leukemia cutis, which can occur in AML. **2. Why the other options are incorrect:** * **A. Acute Lymphoblastic Leukemia (ALL):** Auer rods are never seen in lymphoblasts; they are pathognomonic for myeloid differentiation [1]. DIC is also rare in ALL. * **B. Acute Megakaryocytic Leukemia (AML-M7):** While this is an AML subtype, it is more commonly associated with marrow fibrosis and Down Syndrome (in children <5 years). It does not typically present with the profound DIC seen in APL. * **D. Chronic Myelogenous Leukemia (CML):** CML is a chronic myeloproliferative disorder characterized by a full spectrum of maturing myeloid cells (left shift) and low LAP score [4]. While it features splenomegaly, the presence of Auer rods indicates an "acute" blast-driven process (or a blast crisis) [3]. **3. High-Yield Pearls for NEET-PG:** * **Cytogenetics:** APL is associated with **t(15;17)**, involving the *PML-RARA* fusion gene [2]. * **Morphology:** Look for "Faggot cells" (cells containing bundles of Auer rods) [1]. * **Treatment:** Medical emergency! Treat with **ATRA (All-trans retinoic acid)** and Arsenic Trioxide, which forces the differentiation of promyelocytes. * **DIC Trigger:** Chemotherapy can worsen DIC in APL by causing massive granule release; hence, ATRA is started immediately upon suspicion. **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. 621-622. [2] 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. 620-621. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 611-612. [4] 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. 625-626.
Question 905: A patient presented with fever, night sweats, and weight loss. Clinical examination revealed painless lymphadenopathy. Microscopy shows Reed Sternberg cells. What is the most likely condition?
- A. HIV
- B. Chronic lymphocytic leukemia
- C. Hodgkin's lymphoma (Correct Answer)
- D. Secondary TB
Explanation: **Explanation:** The clinical presentation of fever, night sweats, and weight loss (collectively known as **'B' symptoms**) combined with painless lymphadenopathy is highly suggestive of a lymphoproliferative disorder [3]. The definitive diagnostic clue in this scenario is the presence of **Reed-Sternberg (RS) cells** on microscopy [1]. **1. Why Hodgkin’s Lymphoma (HL) is correct:** RS cells are the hallmark of Hodgkin’s Lymphoma [2]. These are large, multinucleated cells (or cells with bilobed nuclei) featuring prominent eosinophilic nucleoli, often described as having an **"Owl’s eye" appearance** [1]. They are typically derived from B-lymphocytes and are found within a background of non-neoplastic inflammatory cells [2]. **2. Why other options are incorrect:** * **HIV:** While HIV presents with lymphadenopathy and constitutional symptoms, it is a viral infection. Diagnosis is made via ELISA/Western Blot or PCR, not by RS cells. * **Chronic Lymphocytic Leukemia (CLL):** CLL involves a proliferation of small, mature-looking B-cells. Microscopy typically shows **"Smudge cells"** (basket cells) due to the fragility of the lymphocytes, not RS cells. * **Secondary TB:** This presents with similar "B" symptoms and lymphadenopathy (scrofula). However, histopathology would show **caseating granulomas** and Acid-Fast Bacilli (AFB) on Ziehl-Neelsen staining. **High-Yield Clinical Pearls for NEET-PG:** * **Immunophenotype:** Classic RS cells are typically **CD15+ and CD30+**, but **CD45-**. * **Nodular Lymphocyte Predominant HL (NLPHL):** Features "Popcorn cells" (L&H cells) which are CD20+ and CD45+ [4]. * **Most Common Subtype:** Nodular Sclerosis is the most common variant of HL. * **Prognosis:** Lymphocyte Predominant has the best prognosis, while Lymphocyte Depleted has the worst [4]. **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. 616. [2] 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. 614-616. [3] 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. 616-618. [4] 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. 618.
Question 906: A mother is diagnosed with sickle cell disease, and her husband is normal. What are the chances of having children with sickle cell disease and sickle cell trait, respectively?
- A. 0% and 100% (Correct Answer)
- B. 25% and 25%
- C. 50% and 50%
- D. 10% and 50%
Explanation: ### Explanation **1. Understanding the Genetics (The Correct Answer)** Sickle cell disease (SCD) follows an **autosomal recessive** inheritance pattern [3]. To determine the offspring's risk, we use a Punnett square based on the parental genotypes [2]: * **Mother (Sickle Cell Disease):** Genotype **SS** (homozygous affected). * **Father (Normal):** Genotype **AA** (homozygous normal). When we cross **SS × AA**, every child receives one 'S' allele from the mother and one 'A' allele from the father. * **Genotype of all children:** **AS** (100%). * **Phenotype:** **Sickle Cell Trait** (carriers). * **Sickle Cell Disease (SS):** 0% (since the father cannot contribute an 'S' allele). * **Sickle Cell Trait (AS):** 100%. **2. Analysis of Incorrect Options** * **Option B (25% and 25%):** This ratio does not fit any standard Mendelian cross for sickle cell. A 25% risk of disease occurs only when *both* parents are carriers (AS × AS) [2]. * **Option C (50% and 50%):** This occurs if one parent has the disease (SS) and the other is a carrier (AS). In this scenario, the father is normal (AA). * **Option D (10% and 50%):** These percentages are genetically impossible in simple Mendelian inheritance for a single-gene disorder. **3. NEET-PG High-Yield Pearls** * **Molecular Defect:** Point mutation in the β-globin gene on **Chromosome 11**, where Glutamic acid is replaced by **Valine** at the 6th position [1]. * **Screening vs. Gold Standard:** Solubility tests (e.g., Sodium dithionite) are used for screening, but **Hb Electrophoresis** or HPLC is the gold standard for diagnosis. * **Protective Effect:** Sickle cell trait (AS) provides a selective survival advantage against *Plasmodium falciparum* malaria (Heterozygote advantage). * **HbF Importance:** Higher levels of Fetal Hemoglobin (HbF) inhibit polymerization of HbS, which is why Hydroxyurea is used in treatment. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 598-599. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 53-54. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 150-151.
Question 907: Paroxysmal nocturnal hemoglobinuria (PNH) occurs due to a defect in which of the following?
- A. CD 59 (Correct Answer)
- B. CD 15
- C. CD 100
- D. CD 20
Explanation: **Paroxysmal Nocturnal Hemoglobinuria (PNH)** is an acquired clonal hematopoietic stem cell disorder caused by a somatic mutation in the **PIGA gene** [2]. This mutation leads to a deficiency of **GPI (Glycosylphosphatidylinositol) anchors**, which are necessary to attach specific protective proteins to the red blood cell (RBC) membrane. **Why CD 59 is the correct answer:** The two most critical GPI-linked proteins missing in PNH are **CD59 (Membrane Inhibitor of Reactive Lysis)** and **CD55 (Decay Accelerating Factor)**. * **CD59** normally inhibits the formation of the **Membrane Attack Complex (MAC)** (C5b-C9) [1]. * In its absence, RBCs become exquisitely sensitive to complement-mediated lysis, leading to intravascular hemolysis [1]. **Analysis of Incorrect Options:** * **CD 15:** Also known as Lewis X or SSEA-1, it is a marker for Reed-Sternberg cells (in Hodgkin Lymphoma) and mature neutrophils. * **CD 100:** (Sema4D) is a semaphorin protein involved in immune cell signaling and axon guidance; it has no role in PNH. * **CD 20:** A classic B-cell marker targeted by Rituximab; it is not involved in complement regulation or PNH pathogenesis. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Flow Cytometry (shows absence of CD55 and CD59 on RBCs and WBCs) [1]. * **Classic Triad:** Hemolytic anemia, Pancytopenia, and Venous thrombosis (often in unusual sites like the Budd-Chiari syndrome) [1]. * **Screening Test:** Ham’s Test (Acidified Serum Test) and Sucrose Hemolysis Test (now largely replaced by flow cytometry). * **Treatment:** **Eculizumab**, a monoclonal antibody against Complement C5. * **Complications:** PNH can evolve into Aplastic Anemia or Acute Myeloid Leukemia (AML). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 650-651. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 601-602.
Question 908: A peripheral smear shows hypersegmented neutrophils. This finding is most likely due to a deficiency of which of the following?
- A. Vitamin B12 deficiency (Correct Answer)
- B. Folate deficiency
- C. Iron deficiency
- D. Thalassemia
Explanation: **Explanation:** **Hypersegmented neutrophils** (defined as neutrophils with $\geq$ 6 lobes or more than 5% of neutrophils with $\geq$ 5 lobes) are a hallmark of **Megaloblastic Anemia** [1]. 1. **Why Vitamin B12 deficiency is correct:** Vitamin B12 (Cobalamin) and Folate are essential cofactors for DNA synthesis. A deficiency leads to "nuclear-cytoplasmic asynchrony," where the nucleus matures slower than the cytoplasm [2]. In the bone marrow, this results in ineffective erythropoiesis and giant metamyelocytes. In the peripheral blood, this manifests as macrocytic RBCs and hypersegmented neutrophils [3]. While both B12 and Folate cause this, B12 deficiency is the classic association in clinical vignettes unless specific risk factors for folate (e.g., alcoholism, pregnancy) are mentioned. 2. **Why other options are incorrect:** * **Folate deficiency:** While it *also* causes hypersegmented neutrophils, in many standardized exams, B12 is the primary answer unless specified. However, if this were a "Multiple Select" question, both A and B would be correct. * **Iron deficiency:** Characterized by microcytic hypochromic anemia. Neutrophils are typically normal. * **Thalassemia:** A globin chain synthesis defect resulting in microcytic anemia with target cells and basophilic stippling, not hypersegmentation. **High-Yield NEET-PG Pearls:** * **Earliest Sign:** Hypersegmented neutrophils are often the **earliest** peripheral sign of megaloblastic anemia, appearing even before macrocytosis. * **Rule of 5:** Presence of even a single neutrophil with **6 lobes** is diagnostic [1]. * **Macropolycyte:** A term used for these abnormally large, hypersegmented neutrophils. * **Other Causes:** Aside from B12/Folate deficiency, hypersegmentation can be seen in **Uremia** and patients on **Methotrexate** or **Hydroxyurea**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, p. 654. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 130-131. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 593-595.
Question 909: Bone marrow plasmacytosis in multiple myeloma is characteristically more than:
- A. 10%
- B. 20%
- C. 30% (Correct Answer)
- D. 40%
Explanation: **Explanation:** The diagnosis of Multiple Myeloma (MM) has evolved with changing diagnostic criteria. However, for the purpose of standard medical examinations like NEET-PG, the classic morphological hallmark remains a significant increase in plasma cells within the bone marrow [1]. **Why 30% is the Correct Answer:** According to the classic diagnostic criteria (often cited in standard textbooks like Robbins Pathology and the Durie-Salmon staging system), **bone marrow plasmacytosis >30%** is considered a major criterion for the diagnosis of Multiple Myeloma. While the International Myeloma Working Group (IMWG) updated the threshold to ≥10% clonal plasma cells (provided there is evidence of end-organ damage/CRAB features), the "classic" pathological definition taught for competitive exams specifically identifies >30% as the definitive threshold for high-burden plasmacytosis. In advanced disease, infiltration can reach up to 90% [1]. **Analysis of Incorrect Options:** * **A (10%):** This is the minimum threshold for "Clonal Bone Marrow Plasma Cells" under the revised IMWG criteria. While it is the cutoff for Smoldering Myeloma or symptomatic MM (with CRAB features), it is not the "characteristic" high-density infiltration traditionally tested. * **B (20%) & D (40%):** These values do not correspond to any standard diagnostic cutoff for Multiple Myeloma in major classification systems. **High-Yield Clinical Pearls for NEET-PG:** * **Morphology:** Look for "Flame cells" (IgA myeloma), "Mott cells" (grape-like cytoplasmic inclusions), and "Russell bodies" (cytoplasmic) or "Dutcher bodies" (nuclear) inclusions. * **CRAB Criteria:** Calcium (elevated), Renal insufficiency, Anemia, and Bone lesions (punched-out lytic lesions) [3]. * **M-Spike:** Usually >3 g/dL on Serum Protein Electrophoresis (SPEP) [2]. * **Bence-Jones Proteins:** Light chains found in urine that precipitate at 40-60°C and redissolve at 100°C [4]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 617-618. [2] 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. 608-609. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 618-619. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 616-617.
Question 910: CD-15 helps in the assessment of which of the following?
- A. Adult T-cell leukemia
- B. Hodgkin's disease (Correct Answer)
- C. Mycosis fungoides
- D. Larger granular lymphocytic leukemia
Explanation: **Explanation:** **CD15** (also known as Leu M1) is a carbohydrate adhesion molecule expressed on mature neutrophils and certain epithelial cells. In the context of hematopathology, it is a diagnostic hallmark for **Classical Hodgkin Lymphoma (cHL)**. 1. **Why Hodgkin's Disease is Correct:** The characteristic neoplastic cells of cHL, known as **Reed-Sternberg (RS) cells**, typically show a distinct immunophenotype [1][2]. They are characteristically **positive for CD15 and CD30**. The staining pattern for CD15 is typically membranous with characteristic "Golgi zone" (perinuclear dot-like) accentuation. Note: CD15 is usually negative in the Nodular Lymphocyte Predominant subtype of Hodgkin Lymphoma (NLPHL) [3]. 2. **Why Other Options are Incorrect:** * **Adult T-cell leukemia (ATL):** Caused by HTLV-1, these cells typically express T-cell markers (CD2, CD3, CD5) and are characteristically **CD4+ and CD25+**. * **Mycosis fungoides:** This is a cutaneous T-cell lymphoma. The malignant cells are mature T-helper cells, typically expressing **CD3 and CD4**, while often lacking CD7. * **Large Granular Lymphocytic (LGL) Leukemia:** These arise from either cytotoxic T-cells (**CD3, CD8, CD57**) or NK cells (**CD16, CD56**). **High-Yield Clinical Pearls for NEET-PG:** * **RS Cell Immunophenotype:** CD15+, CD30+, CD45 (LCA) negative, and CD20 negative (usually). * **NLPHL Exception:** "Popcorn cells" in NLPHL are **CD20+ and CD45+**, but **CD15- and CD30-** [3]. * **CD15 in Non-Lymphoid Malignancy:** It is also a marker for **Adenocarcinomas**, helping differentiate them from Mesotheliomas (which are CD15 negative). * **B-cell vs. T-cell:** Always remember that RS cells in classical Hodgkin lymphoma are derived from germinal center B-cells, despite their unusual marker profile [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. 614-616. [2] 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. 616. [3] 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. 618.
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