Myeloproliferative Neoplasms Overview

Questions and Answers

What characterizes Myeloproliferative Neoplasms (MPN)?

They are primarily inherited disorders.

They result from viral infections.

They involve abnormalities in pluripotent stem cells. (correct)

They only affect the lymphatic system.

Which of the following is a major diagnostic entity of Myeloproliferative Neoplasms?

Multiple myeloma

Chronic myeloid leukemia (correct)

Severe aplastic anemia

Acute lymphoblastic leukemia

What type of cell proliferation is indicated in Chronic Myeloid Leukemia (CML)?

Massive overproduction of normal-appearing granulocytes (correct)

Overproduction of platelets without differentiation

Increased erythropoietin production

Massive overproduction of lymphocytes

What is a common feature of the mutated stem cells in Myeloproliferative Neoplasms?

They become growth factor independent. Signup and view all the answers

Which of the following is NOT a type of Myeloproliferative Neoplasm?

Chronic lymphocytic leukemia Signup and view all the answers

What role do tyrosine kinases play in Myeloproliferative Neoplasms?

They are constitutively active and lead to abnormal growth. Signup and view all the answers

Which pathophysiological change is commonly associated with Myeloproliferative Neoplasms?

Splenomegaly Signup and view all the answers

What can be an observed result of erythropoietin activity in the context of Myeloproliferative Neoplasms?

Increased red blood cell production due to hypoxia Signup and view all the answers

What is a primary feature of Polycythemia Vera?

Expansion of red cell mass Signup and view all the answers

What mutation is commonly associated with Polycythemia Vera?

JAK2 Signup and view all the answers

Which of the following symptoms is least likely associated with Essential Thrombocythemia?

Hematocrit > 55% Signup and view all the answers

In which disorder is extramedullary hematopoiesis most commonly observed?

Primary Myelofibrosis Signup and view all the answers

How is the platelet count in Essential Thrombocythemia typically characterized?

Sustained above 450,000 /µl Signup and view all the answers

Which laboratory finding is most common in Polycythemia Vera?

High granulocyte count Signup and view all the answers

What clinical manifestation is often seen in patients with Primary Myelofibrosis?

Splenomegaly Signup and view all the answers

Which of the following is typically NOT a clinical symptom of Polycythemia Vera?

Weight gain Signup and view all the answers

What are the key features of fibrosis in peripheral blood?

Leukoerythroblastosis with bizarre shaped red cells Signup and view all the answers

Which of the following accurately describes Myelodysplastic Syndromes (MDS)?

A preleukemic disorder with peripheral pancytopenia Signup and view all the answers

What morphological feature is commonly seen in the bone marrow of patients with advanced fibrosis?

Hypocellular and diffusely fibrotic marrow Signup and view all the answers

Which mutations are commonly implicated in the pathogenesis of Myelodysplastic Syndromes?

Loss-of-function mutations in TP53 Signup and view all the answers

What abnormal findings might be observed in the complete blood count (CBC) of a patient with Myelodysplastic Syndromes?

Increased mean corpuscular volume (MCV) Signup and view all the answers

What genetic mutation is commonly associated with Chronic Myeloid Leukemia (CML)?

t(9;22) Signup and view all the answers

Which symptom is least likely to be an initial clinical feature of Chronic Myeloid Leukemia (CML)?

Shortness of breath Signup and view all the answers

During the chronic phase of CML, what is the typical expected leukocyte count?

Often exceeding 100,000 cells/μL Signup and view all the answers

What laboratory finding is indicative of advanced stages in Chronic Myeloid Leukemia (CML)?

Thrombocytopenia Signup and view all the answers

What is the characteristic feature of the bone marrow in Chronic Myeloid Leukemia (CML)?

Hypercellularity with mild reticulin fibrosis Signup and view all the answers

Which of the following is NOT a phase of disease progression in Chronic Myeloid Leukemia (CML)?

Crisp phase Signup and view all the answers

What is a potential consequence of splenomegaly in individuals with Chronic Myeloid Leukemia (CML)?

Compromised blood supply leading to infarcts Signup and view all the answers

During the blast crisis phase of CML, what percentage of blasts is typically observed in the bone marrow?

20% or more Signup and view all the answers

Study Notes

Myeloproliferative Neoplasms (MPN)

Acquired malignant clonal disorders of pluripotent stem cells affecting one or more cell lines.
Characterized by retained differentiation capacity and growth factor independence due to mutated tyrosine kinases.
Major diagnostic entities include:
- Chronic Myeloid Leukemia (CML)
- Polycythemia Vera (PV)
- Essential Thrombocythemia (ET)
- Primary Myelofibrosis

Chronic Myeloid Leukemia (CML)

Characterized by massive overproduction of normal-appearing granulocytes.
Most common in adults aged 25-60, with peak in the 4th and 5th decades.
95% of cases exhibit t(9;22) (Philadelphia chromosome), creating BCR-ABL fusion gene with tyrosine kinase activity.
Initial nonspecific symptoms include fatigue, anemia, and splenomegaly.
Laboratory findings show elevated leukocyte count (often >100,000 cells/μL) with a predominance of neutrophils.
Bone marrow is hypercellular with mild reticulin fibrosis; spleen shows extramedullary hematopoiesis.

Progression and Prognosis of CML

Progresses through three phases:
- Chronic phase: lasts 1-5 years with mild symptoms.
- Accelerated phase: increasing anemia and new thrombocytopenia.
- Blast crisis: >20% blasts in bone marrow, defined as acute leukemia.
Potential progression to extensive bone marrow fibrosis resembling primary myelofibrosis.

Polycythemia Vera (PV)

Clonal disorder marked by excessive red cell mass due to activating JAK2 mutations.
Symptoms are related to increased blood volume and viscosity, leading to thrombotic events.
Presents insidiously in late middle age with signs including cyanosis, fatigue, and splenomegaly.
Laboratory findings reveal high red cell counts and hematocrit (>55%).

Essential Thrombocythemia (ET)

Clonal disorder characterized by sustained high platelet counts (>450,000/µL).
Associated with risk of hemorrhage and thrombosis; commonly seen in adults over 60.
Bone marrow shows hyperplasia of megakaryocytes with little granulopoiesis or erythropoiesis.
Clinical symptoms include gastrointestinal bleeding and erythromelalgia (pain in palms and soles).

Primary Myelofibrosis

Chronic myeloproliferative disorder with bone marrow fibrosis leading to cytopenia.
Triggered by fibrogenic factors released from neoplastic megakaryocytes.
Peripheral blood presents leukoerythroblastosis and bizarre-shaped erythrocytes.
Bone marrow becomes hypocellular and diffusely fibrotic in advanced stages.

Myelodysplastic Syndromes (MDS)

Preleukemic disorder characterized by ineffective hematopoiesis, leading to cytopenia in the peripheral blood.
High risk of transformation to Acute Myeloid Leukemia (AML).
Commonly affects individuals aged 50 to 70 and may be idiopathic or secondary to therapy.
Pathogenesis involves mutations in transcription and RNA splicing factors, with notable abnormalities in chromosomes.
Morphology includes abnormal hematopoietic precursors like megaloblastoid erythroid cells and ring sideroblasts.

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Description

This quiz explores myeloproliferative neoplasms, focusing on their characteristics and major types like Chronic Myeloid Leukemia. Understand the genetic mutations, clinical presentations, and diagnostic criteria associated with these disorders. Test your knowledge on the classification and pathophysiology of these conditions.