Hematopathology — MCQs

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?

Q236Medium

Which of the following conditions is characterized by increased PT and normal PTT?

Q237Medium

Coagulation defect involving both the arterial and venous system is seen in which of the following conditions?

Q238Easy

Which CD marker is characteristic of histiocytosis?

Q239Medium

Direct Coombs test is positive in hemolytic anemia due to which of the following conditions?

Q240Medium

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

Hematopathology Indian Medical PG Practice Questions and MCQs

Question 231: A 3-year-old female child presented with skin papules. Which of the following is a marker of Langerhans cell histiocytosis?

A. CD 1a (Correct Answer)
B. CD 3
C. CD 68
D. CD 57

Explanation: **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.

Question 232: What is true about iron deficiency anemia?

A. Howel Jolly bodies
B. Anisocytosis (Correct Answer)
C. Polychromasia
D. All of the above

Explanation: In Iron Deficiency Anemia (IDA), the hallmark finding on a peripheral blood smear is a **microcytic hypochromic** picture [1]. **Why Anisocytosis is Correct:** Anisocytosis refers to a variation in the size of Red Blood Cells (RBCs). In the early stages of IDA, the bone marrow produces smaller (microcytic) cells alongside existing normal-sized (normocytic) cells [1]. This variation is quantitatively reflected as an **increased Red Cell Distribution Width (RDW)**. An increased RDW is one of the earliest and most sensitive indicators of IDA, helping to differentiate it from Beta-Thalassemia trait (where RDW is typically normal). **Why Other Options are Incorrect:** * **Howell-Jolly Bodies:** These are nuclear remnants (DNA) seen in RBCs. They are characteristic of **asplenia** (post-splenectomy) or functional hyposplenism (e.g., Sickle Cell Anemia), not IDA. * **Polychromasia:** This represents young, bluish-grey RBCs (reticulocytes) on a Giemsa stain. Polychromasia indicates active erythropoiesis, typically seen in **hemolytic anemias** or after acute blood loss. In IDA, there is a lack of iron to produce new cells, leading to a low reticulocyte count (hypoproliferative state) [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Morphology:** IDA shows microcytic hypochromic cells, **pencil cells** (elliptocytes), and occasionally target cells [1]. * **Best Screening Test:** Serum Ferritin (decreased). It is the first parameter to decrease in iron deficiency. * **Mentzer Index:** MCV/RBC count. If >13, it suggests IDA; if <13, it suggests Thalassemia trait. * **Gold Standard:** Bone marrow aspiration with **Prussian Blue staining** (Perl’s stain) showing absent hemosiderin in macrophages. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 589-591.

Question 233: What is the most common leukemia seen in individuals with Down syndrome?

A. Acute Myeloid Leukemia (AML)
B. Acute Lymphoblastic Leukemia (ALL) (Correct Answer)
C. Chronic Lymphocytic Leukemia (CLL)
D. Chronic Myeloid Leukemia (CML)

Explanation: Children with Down syndrome (Trisomy 21) have a significantly increased risk (10–20 fold) of developing acute leukemia [1]. The correct answer is **Acute Lymphoblastic Leukemia (ALL)** because, statistically, it is the most common leukemia in this population overall [3]. ### **Detailed Explanation** 1. **Why ALL is correct:** While Down syndrome is famously associated with a specific subtype of AML (AMKL), **ALL is the most common leukemia in individuals with Down syndrome over the age of 3.** In the general pediatric population and the Down syndrome population alike, ALL remains the most frequent malignancy [2], [3]. 2. **Why AML is incorrect:** AML (specifically Acute Megakaryoblastic Leukemia, M7) is highly characteristic of Down syndrome, especially in children **under the age of 3**. While the *relative risk* of AML is much higher in Down syndrome than in the general population, the *absolute number* of ALL cases is higher across the entire lifespan. 3. **Why CLL and CML are incorrect:** Chronic leukemias are rare in the pediatric population. Down syndrome specifically predisposes to acute proliferations due to GATA1 mutations (in AML) and JAK2 mutations (in ALL), rather than the mechanisms seen in CLL or CML [1]. ### **NEET-PG High-Yield Pearls** * **Age-Dependent Rule:** * **< 3 years old:** AML (specifically M7 subtype) is more common. * **> 3 years old:** ALL is more common. * **Overall:** ALL is the most common. * **TMD (Transient Myeloproliferative Disorder):** A "leukoid" reaction seen in newborns with Down syndrome, often resolving spontaneously but linked to **GATA1 mutations**. * **Prognosis:** Children with Down syndrome and AML-M7 actually have a *better* prognosis and response to chemotherapy than non-Down syndrome children with the same subtype. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 605-607. [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. 600-602. [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. 598-600.

Question 234: Which of the following is true about acute myelogenous leukemia?

A. Philadelphia chromosome is seen
B. Auer bodies are seen (Correct Answer)
C. Common in childhood
D. Peroxidase negative granules

Explanation: **Explanation:** **Acute Myeloid Leukemia (AML)** is a clonal proliferation of myeloid precursors (blasts) in the bone marrow. 1. **Why Option B is Correct:** **Auer bodies** are pathognomonic for AML (specifically types M1 through M4) [1]. They are needle-shaped, pink/red cytoplasmic inclusions formed by the fusion and crystallization of primary azurophilic granules [2]. Their presence definitively identifies a blast as being of myeloid origin [2]. 2. **Why Option A is Incorrect:** The **Philadelphia chromosome [t(9;22)]** is the hallmark of Chronic Myeloid Leukemia (CML). While it can occur in some cases of B-ALL (associated with poor prognosis), it is not a characteristic feature of AML. 3. **Why Option C is Incorrect:** AML is primarily a disease of **adults** (median age ~65 years) [4]. In contrast, Acute Lymphoblastic Leukemia (ALL) is the most common leukemia in the pediatric population [4]. 4. **Why Option D is Incorrect:** Myeloblasts in AML are typically **Myeloperoxidase (MPO) positive** [2]. Auer bodies themselves are composed of peroxidase-positive material [2]. "Peroxidase negative" granules would point away from a myeloid lineage. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Requires ≥20% blasts in the bone marrow or peripheral blood. * **APML (M3):** Characterized by t(15;17) and "Faggot cells" (bundles of Auer rods) [1]. It carries a high risk of DIC but responds well to All-Trans Retinoic Acid (ATRA) [1]. * **Cytochemistry:** MPO and Sudan Black B (SBB) are the stains of choice for AML. * **Marker:** CD33 and CD13 are common flow cytometry markers for myeloid blasts [3]. **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. 620. [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. 621-622. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 609-611. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 607-608.

Question 235: 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?

A. Bcl-1
B. Bcl-2 (Correct Answer)
C. Bcl-6
D. Bcl-4

Explanation: **Explanation:** The clinical presentation of painless cervical and **epitrochlear lymphadenopathy**, accompanied by B-symptoms (fever, night sweats, weight loss), is highly suggestive of **Follicular Lymphoma (FL)** [1]. In the context of NEET-PG, the involvement of epitrochlear nodes is a classic "buzzword" for Follicular Lymphoma. **Why Bcl-2 is correct:** Follicular Lymphoma is characterized by the hallmark translocation **t(14;18)(q32;q21)** [1],[2]. This translocation moves the **BCL-2 gene** from chromosome 18 to the Immunoglobulin Heavy chain (IgH) locus on chromosome 14 [2]. This leads to the overexpression of the Bcl-2 protein, which is an **anti-apoptotic** molecule [1]. Overexpression prevents programmed cell death in B-cells, leading to their accumulation and tumor formation [2]. **Analysis of Incorrect Options:** * **A. Bcl-1 (Cyclin D1):** Associated with **Mantle Cell Lymphoma**, characterized by t(11;14). It promotes the G1 to S phase transition in the cell cycle. * **C. Bcl-6:** Frequently associated with **Diffuse Large B-Cell Lymphoma (DLBCL)** and Burkitt-like lymphomas. It is involved in the formation of germinal centers. * **D. Bcl-4:** This is a pro-apoptotic member of the Bcl-2 family (also known as BNIP2) and is not a primary driver in common lymphomas. **High-Yield Clinical Pearls for NEET-PG:** * **Translocation:** t(14;18) is the definitive genetic marker for Follicular Lymphoma [2]. * **Histology:** Shows a nodular/follicular pattern of growth; lacks tingible body macrophages (unlike reactive hyperplasia) [1]. * **Immunophenotype:** CD10+, CD19+, CD20+, and **Bcl-2 positive** (Normal germinal centers are Bcl-2 negative) [2]. * **Clinical Course:** Indolent (slow-growing) but can transform into a more aggressive DLBCL (Richter’s transformation). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 561-562. [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. 602-604.

Question 236: Which of the following conditions is characterized by increased PT and normal PTT?

A. Von Willebrand's disease
B. Factor 7 deficiency (Correct Answer)
C. Factor 8 deficiency
D. Thrombin deficiency

Explanation: To understand this question, one must recall the coagulation cascade pathways and the specific laboratory tests used to monitor them. [1] ### **Why Factor VII Deficiency is Correct** * **Prothrombin Time (PT):** Measures the **Extrinsic** and Common pathways. Factor VII is the only factor unique to the extrinsic pathway. Therefore, a deficiency in Factor VII will prolong the PT. [1] * **Activated Partial Thromboplastin Time (aPTT):** Measures the **Intrinsic** and Common pathways (Factors XII, XI, IX, VIII, X, V, II, and I). [1] Since Factor VII is not part of the intrinsic pathway, the aPTT remains **normal**. * **Conclusion:** Isolated Factor VII deficiency is the classic cause of an increased PT with a normal aPTT. ### **Why Other Options are Incorrect** * **Von Willebrand’s Disease (vWD):** vWF stabilizes Factor VIII. Deficiency leads to a secondary decrease in Factor VIII, resulting in a **prolonged aPTT** (or normal in mild cases), but the PT is always normal. [3] * **Factor VIII Deficiency (Hemophilia A):** Factor VIII is part of the intrinsic pathway. Deficiency causes a **prolonged aPTT** with a normal PT. [3] * **Thrombin (Factor II) Deficiency:** Factor II is part of the **Common Pathway**. A deficiency here would prolong **both PT and aPTT**. ### **NEET-PG High-Yield Pearls** 1. **Isolated PT Elevation:** Think Factor VII deficiency or early Vitamin K deficiency (Factor VII has the shortest half-life). [1] 2. **Isolated aPTT Elevation:** Think Hemophilia A (VIII), Hemophilia B (IX), or Factor XI/XII deficiencies. [3] 3. **Both PT and aPTT Elevated:** Think Common pathway defects (Factors X, V, II, I), severe Vitamin K deficiency, Liver disease, or DIC. [2] 4. **Mixing Studies:** If a prolonged PT/aPTT corrects 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. 582-583, 624-625. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 625-626. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 622-623.

Question 237: Coagulation defect involving both the arterial and venous system is seen in which of the following conditions?

A. Factor V Leiden
B. Protein C deficiency
C. Antithrombin III deficiency
D. Hyperhomocystinemia (Correct Answer)

Explanation: **Explanation:** **Hyperhomocystinemia** is the correct answer because it is one of the few prothrombotic states that predisposes to **both arterial and venous thrombosis**. Elevated levels of homocysteine cause endothelial cell injury, promote the oxidation of LDL cholesterol, and increase platelet aggregation. This systemic endothelial dysfunction affects the entire vascular tree, leading to conditions like deep vein thrombosis (venous) as well as myocardial infarction or stroke (arterial). **Analysis of Incorrect Options:** * **Factor V Leiden:** This is the most common cause of inherited thrombophilia [2]. It involves a mutation that makes Factor V resistant to inactivation by Protein C [2]. It primarily causes **venous thromboembolism (VTE)**; it is not a significant risk factor for arterial disease [2]. * **Protein C and Protein S Deficiency:** These natural anticoagulants normally inactivate Factors Va and VIIIa. Their deficiency leads to a hypercoagulable state manifesting almost exclusively as **venous thrombosis** (e.g., DVT, pulmonary embolism) and neonatal purpura fulminans. * **Antithrombin III (ATIII) Deficiency:** ATIII inhibits thrombin and Factor Xa. Deficiency leads to heparin resistance and a high risk of **venous thrombosis**, but it does not typically cause arterial thrombosis. **High-Yield Clinical Pearls for NEET-PG:** * **The "Both" Rule:** Conditions causing both arterial and venous thrombosis include **Hyperhomocystinemia, Antiphospholipid Antibody Syndrome (APS), and Paroxysmal Nocturnal Hemoglobinuria (PNH)** [1]. * **Genetic Basis:** Hyperhomocystinemia can be caused by a deficiency in **Cystathionine β-synthase (CBS)** or a mutation in the **MTHFR** gene. * **Treatment:** Elevated homocysteine levels can often be reduced by supplementing with **Vitamin B6, B12, and Folate**, which are essential cofactors in homocysteine metabolism. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 626-627. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 133-134.

Question 238: Which CD marker is characteristic of histiocytosis?

A. CD1a (Correct Answer)
B. CD1b
C. CD1c
D. CD1d

Explanation: **Explanation:** **Langerhans Cell Histiocytosis (LCH)** is a proliferative disorder of Langerhans cells, which are specialized dendritic cells [1]. The diagnosis relies on identifying specific immunophenotypic markers and ultrastructural features. **Why CD1a is the correct answer:** CD1a is a non-classical MHC class I-like molecule involved in presenting lipid antigens to T-cells. It is the **most specific and characteristic surface marker** used in immunohistochemistry to identify Langerhans cells. In the context of LCH, cells typically express **CD1a, CD207 (Langerin), and S-100**. Among these, CD207 is the most specific as it correlates with the presence of Birbeck granules. **Why the other options are incorrect:** * **CD1b, CD1c, and CD1d:** While these are also members of the CD1 family involved in lipid antigen presentation, they are expressed on different subsets of dendritic cells, B-cells, or cortical thymocytes. They are not used as diagnostic markers for LCH in clinical pathology. Specifically, CD1d is known for presenting glycolipids to Natural Killer T (NKT) cells. **High-Yield Clinical Pearls for NEET-PG:** * **Electron Microscopy:** The pathognomonic finding in LCH is the **Birbeck Granule**, which has a characteristic "tennis-racket" appearance [1]. * **Langerin (CD207):** This is the protein constituent of Birbeck granules and is considered the most specific marker for LCH [1]. * **Clinical Triad (Hand-Schüller-Christian disease):** Calvarial bone defects, exophthalmos, and diabetes insipidus. * **Letterer-Siwe Disease:** The aggressive, multisystem form seen in infants (<2 years) involving skin rash, hepatosplenomegaly, and bone lesions. **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.

Question 239: Direct Coombs test is positive in hemolytic anemia due to which of the following conditions?

A. Paroxysmal cold hemoglobinuria (Correct Answer)
B. Paroxysmal nocturnal hemoglobinuria
C. Hereditary spherocytosis
D. Idiopathic thrombocytopenic purpura

Explanation: ### Explanation **1. Why Paroxysmal Cold Hemoglobinuria (PCH) is Correct:** The Direct Coombs Test (Direct Antiglobulin Test - DAT) detects antibodies or complement proteins bound directly to the surface of red blood cells (RBCs). PCH is an autoimmune hemolytic anemia caused by the **Donath-Landsteiner antibody**, which is an **IgG** antibody with specificity for the **P antigen**. The underlying mechanism involves a "biphasic" process: the antibody binds to RBCs at low temperatures (cold) and fixes complement; when the blood warms up, the antibody dissociates, but the complement cascade is activated, leading to intravascular hemolysis [4]. Because complement (C3d) remains coated on the RBCs, the **Direct Coombs test is positive for complement.** **2. Analysis of Incorrect Options:** * **Paroxysmal Nocturnal Hemoglobinuria (PNH):** This is a stem cell disorder caused by a somatic mutation in the *PIGA* gene, leading to a deficiency of GPI-anchored proteins (CD55/CD59) [2,3]. It is a **non-immune** hemolytic anemia; therefore, the Coombs test is **negative**. * **Hereditary Spherocytosis (HS):** This is an inherited **membrane defect** (deficiency of spectrin, ankyrin, etc.). While spherocytes are seen on the blood film, they are due to genetic structural weakness, not antibody coating [4]. The Coombs test is **negative**. * **Idiopathic Thrombocytopenic Purpura (ITP):** This is an immune-mediated destruction of **platelets**, not RBCs [5]. While it is an autoimmune condition, it does not typically cause a positive Direct Coombs test unless it occurs in association with autoimmune hemolytic anemia (known as **Evans Syndrome**). **3. NEET-PG High-Yield Pearls:** * **Warm AIHA:** Most common; IgG mediated; positive for IgG ± C3 [4]. * **Cold Agglutinin Disease:** IgM mediated; positive for **C3 only** (IgM dissociates) [1]. * **PCH:** Associated with viral infections in children and syphilis in adults. * **Drug-induced Hemolysis:** Alpha-methyldopa is a classic cause of a positive Direct Coombs test [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 651-652. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 601-602. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 650-651. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 602-603. [5] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 666-667.

Question 240: All of the following statements about Hairy cell leukaemia are true except?

A. Splenomegaly is conspicuous
B. Results from an expansion of neoplastic T lymphocytes (Correct Answer)
C. Cells are positive for Tartarate Resistant Acid phosphatase
D. The cells express CD25 consistently

Explanation: **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.

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Hemolytic Anemias

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Acute Leukemias

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Chronic Leukemias

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Plasma Cell Disorders

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