A 65-year-old patient presented to the medicine OPD with weakness and fatigue for 6 months, accompanied by mild abdominal discomfort. On examination, moderate splenomegaly was noted. Laboratory findings revealed severe normocytic normochromic anemia, neutropenia with monocytopenia, and thrombocytopenia. Bone marrow aspiration was performed to investigate the cause of decreased cell counts, but the tap was dry. Therefore, a bone marrow biopsy was conducted. Which of the following CD markers is NOT typically positive in hairy cell leukemia?
A 45-year-old woman presents with marked splenomegaly, a leukocyte count of 300,000/μL, and a differential count showing a predominance of myelocytes, metamyelocytes, bands, and segmented neutrophils, along with increased basophils and platelets, without anemia. Leukocyte alkaline phosphatase is decreased. Which of the following describes a major characteristic of chronic myeloid leukemia?
What is the most common type of lymphoma observed in post-transplant patients?
Among the following AML subtypes, non-specific esterase (NSE) staining is typically NEGATIVE in which one?
What is the causative agent of Adult T-cell Leukemia/Lymphoma (ATLL)?
A peripheral smear with increased neutrophils, basophils, eosinophils, and platelets is highly suggestive of:
Cells seen in cutaneous T-cell lymphoma are called?
A 5-year-old boy presented to the emergency room with vomiting and abdominal distension. Abdominal imaging showed a mass in the ileocecal region. Histopathological examination of a biopsy from the region showed a diffuse infiltrate of lymphoid cells admixed with macrophages, giving a "starry-sky" appearance. Which of the following translocations is least likely to be seen in Burkitt lymphoma?
Which of the following is not a myeloproliferative disorder?
Which is the most common mutation in hereditary spherocytosis?
Explanation: ***CD117*** - CD117 (c-Kit) is a transmembrane receptor tyrosine kinase typically expressed on hematopoietic stem cells, mast cells, and gastrointestinal stromal tumors (GIST). - It is generally **negative in hairy cell leukemia**, making it a useful marker to differentiate HCL from other lymphoproliferative disorders. - This is the correct answer as the question asks which marker is NOT typically positive in HCL. *CD11c* - CD11c is a beta-2 integrin subunit that is **strong and consistently expressed** on the surface of hairy cells. - It is a key diagnostic marker for hairy cell leukemia due to its high expression. *CD103* - CD103 (alpha-E integrin) is another **highly characteristic marker for hairy cell leukemia**, showing strong expression on hairy cells. - Its presence helps confirm the diagnosis and distinguish HCL from other B-cell lymphomas. *CD25* - CD25 (alpha chain of the IL-2 receptor) is also **typically expressed** on hairy cells, although its expression can be more variable or less intense than CD11c and CD103 [1]. - Along with CD11c and CD103, CD25 contributes to the characteristic immunophenotype of hairy cell leukemia [1]. *Clinical Presentation and Bone Marrow* - Hairy cell leukemia typically presents with splenomegaly and pancytopenia. Because the leukemic cells are enmeshed in an extracellular matrix of reticulin fibrils, they usually cannot be aspirated, resulting in a "dry tap" [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, p. 612.
Explanation: ***9;22 translocation*** - The presence of leukocytosis with myelocyte predominance and splenomegaly suggests a myeloproliferative disorder, specifically Chronic Myeloid Leukemia (CML) [2]. - The **9;22 translocation** leading to the BCR-ABL fusion gene is a hallmark of CML, indicating its role in the pathogenesis of the disease [1]. *Expansion of mature B lymphocytes within multiple lymph nodes* - This description is more characteristic of **chronic lymphocytic leukemia (CLL)** or lymphomas rather than CML. - CML primarily affects **myeloid lineage**, not B lymphocytes, and typically does not exhibit marked lymphadenopathy. *Hypogammaglobulinemia* - Hypogammaglobulinemia is associated with disorders that affect antibody production, but is not a major characteristic of CML. - In fact, CML may present with **normal or elevated immunoglobulin levels** at diagnosis. *Neoplastic cells exhibiting hair-like filamentous projections* - This feature describes **hairy cell leukemia**, not CML, which is characterized by myeloid proliferation. - CML presents with atypical myeloblasts and myeloid cells, rather than the unique cellular morphology seen in hairy cell leukemia. **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. 624. [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. 625-626.
Explanation: ***B cell*** - The vast majority of **post-transplant lymphoproliferative disorders (PTLD)**, which are common in transplant patients, arise from **B lymphocytes** [1]. - This is primarily due to the **immunosuppression** compromising T-cell control over **Epstein-Barr virus (EBV)**, which then drives B-cell proliferation [1]. *T cell* - While T-cell PTLD can occur, it is significantly **less common** than B-cell PTLD in the post-transplant setting. - T-cell lymphomas generally have **different epidemiological and pathogenetic profiles** compared to B-cell PTLD. *Null cell* - **Null cell lymphomas** are rare and do not express typical T-cell or B-cell markers. - They are not considered a common form of PTLD in transplant recipients. *NK cell* - **Natural killer (NK) cell lymphomas** are also rare and represent a small fraction of all lymphomas. - They are not typically associated with the common mechanisms or incidence of PTLD in transplant patients. **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. 595-596.
Explanation: ***Acute Promyelocytic Leukemia (M3)*** - Non-specific esterase (NSE) is **negative** in Acute Promyelocytic Leukemia (M3) because NSE primarily stains cells of the **monocytic lineage**. - M3 is characterized by abnormal **promyelocytes** with heavy granulation, which are granulocytic precursors without monocytic differentiation. - M3 shows strong positivity for **myeloperoxidase (MPO)** instead, which is the characteristic marker for granulocytic lineage. *Acute Myelomonocytic Leukemia (M4)* - NSE staining is **positive** in M4 because this subtype has both myeloid and **monocytic components**. - The monocytic component (≥20% of non-erythroid cells) stains positively with NSE, which helps differentiate it from pure myeloid leukemias. - NSE positivity (inhibited by sodium fluoride) is a key diagnostic feature alongside myeloperoxidase positivity. *Acute Erythroleukemia (M6)* - NSE is typically **negative** in the predominant erythroid component of M6. - The diagnosis of M6 relies on the presence of ≥50% erythroid precursors (which are PAS positive) and ≥20% myeloblasts among non-erythroid cells. - NSE is not a characteristic marker for erythroleukemia. *Acute Monocytic Leukemia (M5)* - NSE staining is characteristically **strongly positive** in M5, which primarily consists of **monoblasts and promonocytes**. - This strong NSE positivity (inhibited by sodium fluoride) is a defining diagnostic feature demonstrating pure monocytic differentiation. - M5 typically shows weak or negative myeloperoxidase, helping distinguish it from other AML subtypes.
Explanation: ***HTLV-1 (Human T-lymphotropic virus type 1)*** - **HTLV-1** is definitively linked to the pathogenesis of **Adult T-cell Leukemia/Lymphoma (ATLL)**, a rare but aggressive form of T-cell malignancy. - The virus **immortalizes** and **transforms CD4+ T-cells**, leading to uncontrolled proliferation and the development of leukemia/lymphoma. *HIV* - **HIV** primarily causes **Acquired Immunodeficiency Syndrome (AIDS)** by targeting CD4+ T-cells, leading to their destruction and systemic immune dysfunction. - While HIV-infected individuals have an increased risk of certain lymphomas, these are typically **B-cell lymphomas** (e.g., diffuse large B-cell lymphoma, primary central nervous system lymphoma) and are linked to immune suppression, not directly caused by HIV transforming T-cells into ATLL. *EBV (Epstein-Barr Virus)* - **EBV** is associated with various **lymphoproliferative disorders** and cancers, often of B-cell origin, such as **Burkitt lymphoma**, Hodgkin lymphoma, and nasopharyngeal carcinoma. - While it infects B-cells and can cause transformation, it is not the causative agent for primary T-cell leukemias like ATLL. *HTLV-2 (Human T-lymphotropic virus type 2)* - **HTLV-2** is related to HTLV-1 but is generally **not associated with malignancy**. - It is implicated in some neurological disorders but has not been shown to cause ATLL or any other T-cell leukemia/lymphoma.
Explanation: ***Chronic myelogenous leukemia*** - Characterized by a **marked increase in granulocytes** (including neutrophils, basophils, and eosinophils) and often presents with **thrombocytosis** (increased platelets) [1]. - The presence of these cell types in combination aligns with the typical **myeloid cell proliferation** seen in CML [2]. *Acute lymphoblastic leukemia* - Primarily involves **lymphoblasts** and typically presents with a predominance of **lymphocytes**, not myeloid cells. - Does not typically show the **elevated basophil and eosinophil counts** seen in this case. *Myelodysplastic syndrome* - Usually characterized by **ineffective hematopoiesis** leading to cytopenias in various lineages rather than increased counts. - There's no significant rise in myeloid cells; this disorder typically presents with poor-quality cells and potential progression to leukemia. *Acute myeloid leukemia* - Features predominantly **myeloblasts** and usually presents with a rapid decline in blood cell counts, not an increase. - While it presents with myeloid proliferation, it lacks the characteristic **chronic progression** and the increase in basophils and eosinophils seen in CML. **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. 625-626. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 611-612.
Explanation: ***Sezary cells*** - Characteristic of cutaneous T-cell lymphoma, particularly in **Sezary syndrome**, where malignant T-cells circulate in the blood [1,2]. - These cells exhibit **abnormal morphology**, including significant **pleomorphism** and a **cerebriform nucleus** [1,2]. *Dohle bodies* - Dohle bodies are indicative of **cytoplasmic inclusions** in neutrophils, often seen in infections or inflammatory conditions. - They are **not associated** with cutaneous T-cell lymphoma and do not represent malignant lymphoid cells. *Barr bodies* - Barr bodies are **inactivated X chromosomes**, typically present in female cells, and are unrelated to any form of lymphoma. - They do not indicate the presence of malignant **T-cells** or any form of cutaneous T-cell malignancy. *Councilman bodies* - Councilman bodies are **apoptotic hepatocytes** seen in liver pathology, particularly in viral hepatitis or toxic injury. - They bear no relation to cutaneous T-cell lymphoma or to any **lymphoid** malignancies. **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. 564-565. [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. 613-614.
Explanation: ***t(8;22)*** - This translocation is commonly associated with **Burkitt lymphoma**, which presents with a **starry-sky appearance** on histopathology due to the high proliferation of lymphoid cells and macrophages [1]. - It often occurs in the **abdominal region** and is characterized by rapidly growing tumors typically seen in pediatrics, aligning with the case of the 5-year-old boy. *t(11;14)* - Primarily associated with **Mantle cell lymphoma**, which typically presents in older adults, and not usually in the pediatric population. - This translocation involves the **BCL-1 gene**, leading to overexpression of cyclin D1, and does not match the histological features described. *t(2;8)* - This translocation is linked to **Lymphoblastic lymphoma** and some variants of **Burkitt lymphoma**, but it is less common compared to t(8;14) and t(8;22). - It involves the **MYC gene**, but the specific clinical and histological features described do not fit this option. *t(8;14)* - While this translocation is associated with Burkitt lymphoma, it involves the **myc oncogene and immunoglobulin heavy chain locus**, affecting a different presentation profile [2]. - It usually manifests with **extranodal masses**, particularly in the jaw or abdomen, but does not align specifically with the features outlined in this case. **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. 606. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 324-325.
Explanation: ***Acute myeloid leukemia*** - *Acute myeloid leukemia (AML)* is a **myeloid neoplasm** characterized by the rapid proliferation of myeloid cells and is classified as an acute leukemia, not a myeloproliferative disorder. - It involves **highly abnormal cells** that impede normal blood cell production, contrasting with chronic myeloproliferative disorders which have a more gradual progression. *Essential thrombocytosis* - This is a true **myeloproliferative disorder** characterized by an **increase in platelet count** and is due to the increased production of megakaryocytes in the bone marrow [1]. - Patients can present with thrombotic or hemorrhagic complications, supporting its classification as a myeloproliferative neoplasm. *Chronic myeloid leukemia* - Chronic myeloid leukemia (CML) is another type of **myeloproliferative disorder**, arising from a genetic mutation leading to excessive production of myeloid cells. - It is associated with the **Philadelphia chromosome** and typically presents in a chronic phase with variable leukocytosis. *Polycythemia vera* - Polycythemia vera is a **myeloproliferative neoplasm** characterized by hyperproduction of red blood cells, often accompanied by leukocytosis and thrombocytosis [1]. - It is associated with mutations in the **JAK2 gene**, leading to increased erythropoiesis and elevation of hemoglobin levels, confirming its classification [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 614-615.
Explanation: ***Ankyrin*** - The most common mutation in hereditary spherocytosis is in the **ankyrin gene**, which disrupts the spectrin-actin cytoskeleton structure in red blood cells [1]. - This leads to **decreased membrane stability**, causing the spherocytes to be more prone to hemolysis [1]. *Band 3* - Mutations in the **Band 3 protein** can also occur in hereditary spherocytosis but are less common compared to ankyrin mutations [1]. - Band 3 primarily affects **chloride-bicarbonate exchange** but does not represent the most prevalent mutation in this condition. *Glycophorin* - Glycophorin mutations are typically associated with **hereditary elliptocytosis**, not with hereditary spherocytosis. - This oes not relate to the pathophysiology of spherocytosis, which involves cytoskeletal proteins. *Spectrin* - While **spectrin** is crucial for maintaining the cell membrane's integrity, mutations here are not the most frequently observed in hereditary spherocytosis cases [1]. - Spectrin mutations can cause red blood cell shape abnormalities but are overshadowed by ankyrin-related mutations in terms of prevalence. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 640-641.
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