MDS1 Flashcards

1
Q

2 main features that characterize myelodysplastic syndrome (MDS

A
  1. ineffective hematopoiesis:

2. increased risk of transformation to acute leukemia:

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2
Q

Ineffective hematopoiesis in MDS

A

○ The clone (hematopoietic stem cells) is not able to make normal functioning blood cells.
○ Cells often die before leaving the marrow, and usually look abnormal (dysplastic)

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3
Q

MDS increased risk of transformation to acute leukemia

A

hematopoietic stem cell clone slowly acquires enough abnormalities → outright AML

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4
Q

2 clinical scenarios of MDS

A
  1. Primary (idiopathic) MDS

2. Secondary / therapy-related (t-MDS)

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5
Q

Primary (idiopathic) MDS

  • Type of onset?
  • Age group:
  • Median age of dx:
  • Incidence:
A

○ Insidious onset
○ Usually people >50
○ Median age of dx:70
○ Incidence: 3-5 cases/100,000 persons per year

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6
Q

Secondary / therapy-related (t-MDS)

  • Type of onset?
  • types of therapy leading to MDS
A
  • 2-8 years latency
  • use of alkylating agent
  • use of topo II
  • Exposure of active marrow to ionizing radiation
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7
Q

List 3 different types of tests that could be performed to make a diagnosis of MDS.

A

1) Morphologic evidence of dysplasia in marrow
2) Increased myeloblasts, but less than 20% of blood and marrow cells
3) Presence of a clonal cytogenetic abnormality

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8
Q

Morphologic evidence of dysplasia in marrow for MDS

A

Dyshematopoiesis: > 10% of cell are dysplastic

  • Dyserythropoiesis
  • Dysgranulopoiesis
  • Dysmegakaryopoiesis
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9
Q

Dyserythropoiesis

A

RBC precursors with nuclear budding, irregularly-shaped nuclei, lack of coordination between nuclear and cytoplasmic maturation, increased ring sideroblasts

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10
Q

Dysgranulopoiesis

A

Nuclear hypolobation of mature neutrophils, including neutrophils with bilobed nuclei called pseudo-Pelger-Huet cells, also cytoplasmic hypogranularity of neutrophils

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11
Q

Dysmegakaryopoiesis

A

Megakaryocytes with hypolobated or non-lobated nuclei, often hyperchromatic nuclei, megakaryocytes often of small size

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12
Q

4 possible causes of secondary myelodysplasia that might mimic MDS.

A
  1. Certain drugs, including many chemotherapeutic drugs
    - use of alkylating agent
    - use of topo II
    - ionizing radiation
  2. Vitamin deficiency (B12, folate, ect)
  3. Viral infection
  4. Toxin exposure (heavy metals such as arsenic)
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13
Q

LOW GRADE MDS:

A
  • Myeloblasts are not increased in frequency
  • Refractory Cytopenia with Unilineage Dysplasia (RCUD): good prognosis
  • Refractory Cytopenia with Multilineage Dysplasia (RCMD): worse prognosis
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14
Q

HIGH GRADE MDS

A
  • Myeloblasts are increased in frequency, (less than 20%)
  • Refractory Anemia with Excess Blasts-1 (RAEB-1) : dismal prognosis
  • Refractory Anemia with Excess Blasts-2 (RAEB-2): VERY dismal prognosis
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15
Q

MDS vs. MPNs:

- source of disease

A

MDS: marrow is REPLACED by a malignant clone, derived from a transformed stem cell or progenitor cell
MPS: Clonal hematopoietic NEOPLASM arising from a transformed hematopoietic stem cell

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16
Q

MDS vs. MPNs:

- onset

A

Both insidious

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17
Q

MDS vs. MPNs:

- hematopoiesis effectiveness

A

MDS: ineffective
- marrow replaced by malignant clone
MPNs: effective
- marrow fibrosis

18
Q

MDS vs. MPNs:

- ability to develop into acute leukemia

A

Both

19
Q

MDS vs. MPNs:

- age group

A
MDS: 
- usually >50 
- median age of dx: 70
MPNs: 
- middle-aged to early adults 
- rare in children
20
Q

2 reasons for the frequent occurrence of splenomegaly and hepatomegaly in patients with MPNs

A
  1. spleen sequestering RBCs because they make too many

2. Extramedullary hematopoeisis, causes liver and spleen to enlarge

21
Q

3 possible negative end points for MPNs.

A

• Without treatment, get:
○ Marrow fibrosis
○ Bone marrow failure
○ Transformation to acute leukemia (less common for MPN than MDS)

22
Q

4 MPNs

A
  1. Chronic Myelogenous Leukemia (CML)
  2. Polycythemia Vera (PV)
  3. Primary Myelofibrosis (PMF)
  4. Essential Thrombocythemia (ET)
23
Q

Chronic Myelogenous Leukemia (CML)

  • What is it?
  • blood cell count?
A

CML is an MPN that manifests primarily as a persistent neutrophilic leukocytosis
○ Blood cell counts:
§ Often incidental diagnosis due to abnormal CBC results
§ WBC ranges from 12,000 – 1,000,000 (averages 100,000)

24
Q

Chronic Myelogenous Leukemia (CML)

Phases

A

• Marrow findings:

  1. Initial Chronic phase (stable)
  2. Accelerated Phase (Intermediate phase -may or may be bypassed to Blast phase)
  3. Blast phase
25
Q

Chronic Myelogenous Leukemia (CML)

marrow findings

A
  1. Initial Chronic phase (stable)
    □ Prominent leukocytosis due to a prominent neutrophilia
    □ Increased basophils in blood
    □ Increased platelets in blood
    □ Markedly hypercellular bone marrow with prominent granulocytic hyperplasia
  2. Blast phase:
    □ 20% or more blasts in the marrow or blood
26
Q

Chronic Myelogenous Leukemia (CML)

- cytogenic abnormality

A

§ BCR-ABL1 fusion gene (must have this for diagnosis)

□ Der(22)t(9:22)→ Philadelphia chromosome

27
Q
Polycythemia Vera (PV) : 
- Blood cell counts
A

Lots of RBCs due to RBCs “really”
- PV usually is diagnosed in a polycythemic phase with:
□ increased blood cell counts
□ Increased neutrophils and platelets in the blood

28
Q

polycythemic phase vs Spent phase (post PV myelofibrosis)

A

polycythemic phase: increased blood cell counts

Spent: Fall in blood cell count

29
Q
Polycythemia Vera (PV) : 
- marrow findings
A

§ Trilineage hyperplasia in the marrow
§ Clusters of bizarre megakaryocytes
§ Spent phase/post-PV myelofibrosis:
□ Extensive marrow fibrosis → marrow failure

30
Q
Polycythemia Vera (PV) : 
- cytogenic abnormalities
A

Activating mutation of JAK2, usually a V617F point mutation.

31
Q
Primary Myelofibrosis (PMF) 
- Blood cell counts:
A
Q 
Prefibrotic stage: 
□ ↑ Platelets in blood 
□ ↑ neutrophils in blood
Progress to fibrotic stage: 
□ Falling blood cell count 
□ Leukoerythroblastosis of blood
32
Q
Primary Myelofibrosis (PMF) 
- Marrow finding
A

Prefibrotic stage:
□ Granulocytic and megakaryocytic hyperplasia, but no erythrocytosis
□ Bizarre megakaryocytes in marrow
Progress to fibrotic stage:
□ Significant reticulin (collagen) fibrosis of the marrow
□ Bone marrow failure

33
Q
Primary Myelofibrosis (PMF) 
- Cytogenic abnormality
A

§ JAK2 mutations are present in around 50% of PMF cases

§ Cases lacking JAK2 mutations often have mutations of MPL or CALR

34
Q
Essential Thrombocythemia (ET) 
what is it? How is it different from PMF
A

ET is an MPN characterized by a persistent thrombocytosis.

  • Lacks the marrow granulocytic hyperplasia often seen in PMF,
  • atypical megakaryocytes in ET are even larger than those in PMF
35
Q
Essential Thrombocythemia (ET) 
- blood cell count
A

§ Persistent thrombocytosis (↑ platelet count)

§ 50% of ET patients are diagnosed based on CBC results while asymptomatic

36
Q
Essential Thrombocythemia (ET) 
- Cytogenic abnormality
A

§ JAK2 mutations are present in around 50% of ET cases

§ Cases lacking JAK2 mutations often have mutations of MPL or CALR

37
Q

most common method of death attributable to disease in polycythemia vera (PV) patients

A

venous or arterial thrombosis, leading to complications such as DVT, MI, and stroke

38
Q

3 sites where thrombosis should always make one consider the possibility of PV

A
○ Thrombosis of:
1. mesenteric vein, 
2. portal vein 
3. splenic vein 
should always raise the Possibility of PV.
39
Q

most common treatment for PV.

A

○ Serial phlebotomy
○ Aspirin therapy (to help prevent clots)
○ If symptoms are problematic, mild chemotherapy can be used, but this increases risk of transformation to acute leukemia

40
Q

peripheral blood smear of a patient with leukoerythroblastosis

A

Presence of immature granulocytes and immature (nucleated) red cells

41
Q

Peripheral blood smear of pt w/ primary marrow fibrosis (PMF)

A

Leukoerythroblastosis in primary fibrotic stage

42
Q

Peripheral blood smear of pt w/ primary marrow fibrosis (PMF)

A

Leukoerythroblastosis in primary fibrotic stage