deck_4820548 Flashcards
What is acute leukemia?
- Acute leukemia is a clonal, neoplastic proliferation of immature myeloid or lymphoid cells (two types as a result: AML and ALL)
- Acute means it is rapidly fatal without treatment
How does acute leukemia work?
Immature leukemic cells that do not mature past a blast or other precursor stage accumulate in bone marrow and cause bone marrow dysfunction and there for loss of peripheral blood cells
What is the etiology of AML?
Chromosomal abnormalities affecting oncogenes, TS, or regulation of apoptosis lead to inability for cells to mature/differentiate and for them not to be regulated by external factors for growth and also inexhaustibly self-renews
For AML, genetic disturbance at myeloid precursor –> AML types affecting myeloid lineages (granulocytes, monocytes, eythrocytes, megakaryocytes)
What is the etiology of ALL?
Similar to AML, but defect in lymphoid stem cell –> either B cell or T cell affected, but these cells don’t fully mature75% of ALL cases occur in kids
What are risk factors for acute leukemia?
Chemotherapy (especially DNA alkylating agents and topoisomerase II inhibitors), smoking, ionizing radiation, benzene, other genetic syndromes (Down, Bloom, Fanconi anemia, ataxia-telangiectasia)
What are the signs and symptoms of acute leukemia?
Same things related to cytopenia: anemia (fatigue, dyspnea), thrombocytopenia (bruising, hemorrhage) neutropenia (fever/infection)
However, sometimes present due to leukemic cells: thrombosis due to inc. WBC –> inc. blood viscosity, DIC initiated by WBCs, and can infiltrate mucouse membranes
What expresses CD34?
Immature lymphoblasts and myeloblasts
What expresses TdT?
Only lymphoblasts (no myeloblasts and no lymphocytes)
What do B-lymphoblasts express?
CD19, CD22, and/or CD79a, but not CD20 or surface Ig
Describe the cytogenetics of BALL
1) t(9:22)(q34;q11.2); BCR-ABL1 [Philadelphia chromosome]
- 25% of adult cases (2% of child)
- worst prognosis
2) 11q23; MLL
- neonates/young infants
- poor prognosis
3) t(12:21)(p13;q22); ETV6-RUNX1
- 23% of childhood BALL
- very favorable prognosis
Describe T-ALL
Only 25-30% of ALL casesIn adolescents/young adults primarily
Presents more commonly with LBL with masses
More likely to present with high WBC
Males>females
What do T-lymphoblasts express?
CD2, CD3, and/or CD7; also CD4, CD8; also CD99, CD1a
What are other prognostic factors for ALL aside from cytogenetic findings?
Worse prognosis for 10yo/adults
Worse if WBC is elevated
Worse if hypodiploidyWorse if T-ALL
What is the diagnostic criteria for AML?
Either myeloblasts accounting for >20% of nucleated cells in the marrow/peripheral blood (detected through smears, flow cytometry, or immunohistochemistry on marrow biopsy) OR one of the genetic mutations
What do immature myeloblasts express?
CD34 (but also on lymphoblasts), CD117, myeloperoxidase,
For monocytic diff –> CD64, CD14
For megakaryoblastic diff –> CD41, CD61
Also contain Auer rods (which help to distinguish from lymphoblasts)
Describe the cytogenetics of AML
Typically balanced translocations
1) t(8;21)(q22;q22); RUNX1-RUNX1T1
- 5% of cases
- AML w/ maturation (some neutrophil production)
- blocked transcription of CBF-dep genes –> blocked differentiation
- good prognosis
2) inv(16)(p13.1;q22) or t(16;16)(p13.1;q22); CBFB-MYH11
- 5-10% of cases
- lots of immature eosinophils with abnormal basophilic granules (baso eos)
- inc. myeloblasts and monocytes (myelomonocytic leukemia)
- similar to CBF in (1)
- good prognosis
- 3) t(15;17)(q22;q12);PML-RARA
- important
- promyelocytes instead of blasts
- 5-10% of cases
- hypergranular (normal promyelocytes with lots of granules, Auer rods)
- retinoic acid receptor alpha (RARA) needed for promyelocytes to deveop, but can overcome by giving retinoic acid
- can cause DIC**
4) t(1;22)(p13;q13);RBM15-MKL1
- megakaryoblastic diff
- seen in infants w/ Down syndrome
- good prognosis w/ chemo
5) 11q23; MLL
- monocytic diff
- poor prognosis
Describe the differences between therapy related AML secondary to alkylating agents/radiation and topoisomerase II inhibitors
AA/radiation
- 2-8yrs of latency
- goes through MDS before AML- whole or partial loss from chromosome 5 and/or 7
topoisomerase II inh
- 1-2 years of latency
- de novo AML skipping MDS
- rearrangement of MLL gene (11q23)
both have poor prognoses
What if there are no cytogenetic findings but you suspect AML?
Then called AML, NOS (not otherwise specified) and you look at differentiation of leukemic cells:
- myeloid if myeloblasts
- myelomonocytic if myeloblasts and monoblasts/monocytes
- monoblastic/monocytic if monoblasts and monocytes (may infiltrate skin)
- eyrthroid if myeloblasts but erythroid precursors are inc- megakaryblastic
- if megakaryoblasts/cytes and have marrow fibrosis
However, are finding some genetic abnormalities:
- FLT3 ITD: poor prognosis
- NPM1 - good prognosis
- CEBPA - good prognosis
What about overall prognosis of AML?
If poor prognosis, then 10years
60% of AML will go into remission after chemo
Stem cell transplant is preferred treatment
What two factors characterize MDS?
Ineffective hematopoiesis and increased risk of transformation to AML
(basically similar to AML)
How do you diagnose MDS?
Look for 2+ cytopenias: anemia, thrombocytopeia, or neutropenia
Look at marrow- >10% of cells should show dysplastic changes
- dyserythropoiesis - RBC precurosors with moth-eaten and/or multi-lobed nuclei, sideroblastic
- dysgranulopoiesis - moth eaten bi-lobed (Pelger-Huet) nuclei, abnormally pale (instead of pink) cytoplasm due to lack of granules
- dysmegakaryopoiesis - small and single lobed nuclei
Look at cytogenetics- partial or whole deletions of chr 5 and/or 7, deletion 7q, deletion 5q, trisomy 8
If no cytogenetics or increased myeloblasts and only dysplasia, then what (MDS)?
Then need to exclude findings due to:
- chemo
- B12/folate def
- viral infection
- toxins
What is low and high grade MDS?
Low grade: myeloblasts 5% of marrow and/or >2% of peripheral
What are the types of low grade MDS?
Refractory cytopenia with unilineage dysplasia
- good prognosis
- low grade MDS with dysplasia in only one lineage (usually anemia)
Refractory cytopenia multilineage dysplasia
- worse prognosis
- 2+ lineagesMDS w/ isolated deletion 5q- anemia, inc platelets, megakar with small, round, non lobed nuclei
What are the high grade MDS?
Refractory anemia w/ excess blasts 1- 5-9% blasts in marrow or 2-4% in peripheral blood
RAEB2
- 10-19% in marrow, 5-19% in peripheral bloodbad prognosis
Why do MPNs present with hepatosplenomegaly?
because of the sequestration of excess blood cells and extramedullary hematopoiesis
What can happen in MPNs if not treated?
can transform to AML
can transform to MDS
can have marrow fibrosis
What are the 4 types of MPNs?
Chronic myelogenous leukemia (CML) Polycythemia vera (PV) Primary myelofibrosis (PMF) Essential thrombocythemia (ET)
What are the initial symptoms of CML?
Fatigue, weight loss, night sweats, splenomegaly, anemia
But can be asympotmatic and diagnosed by CBC indicating inc neutrophil
Describe the progression of CML
Starts in chronic phase
- blasts not elevated
- neutrophils elevated
- basophils and platelets are often increased
- hypercellular due to granulocytic hyperplasia
- small, round, non-lobed nuclei megakaryocytes
- no dysplasia
If not treated, moves to blast phase
- basically AML (>20% blasts in marrow/blood)
- blasts usually myeloblasts (70%) or lymphoblasts (30%)
Describe the cytogenetics of CML
BCR-ABL1 gene fusion
t(9;22)9q34;q11.2) - Philadelphia chromosome
Results in 210 kD fusion protein as opposed to 190 kD in BALL
How do you treat and diagnose CML?
Diagnose with karyotype or FISH and look for BCR-ABLPTKIs (protein tyrosine kinase inhibitors) - Gleevec;
What is polycythemia vera characterized by?
Increase in RBC mass and inc neutrophils and platelets (trilineage hyperplasia)
Large, weird megakaryocytes
Mutation of JAK2 gene with V617F point mutation
If the JAK2 mutation isn’t found in PV, what could it be?
If persistent erythrocytosis, then maybe secondary erythrocytosis seen in smokers and chronic hypoxia
Describe the progression of PV
Starts in a polycythemic phase with inc peripheral blood
Progresses to spent phase where marrow fibrosis and peripheral blood dec and becomes similar to PMF
What other symptoms are associated with PV?
Symptoms include headache, dizziness, visual problems, paresthesias, plethora, itching, splenomegaly (70%), and hepatomegaly (40%)
Thrombosis of mesenteric, portal, or splenic vein
How do you treat PV?
Good prognosis
Phlebotomy (bloodletting) with aspirin to prevent clots
Mild chemo
What is PMF characterized by?
Proliferation of granulocytic and megakaryocytic lineages –> progressing to myelofibrosis (similar to PV but no erythrocytosis)
JAK2 mutations in 50% of cases
What is the course of PMF?
In prefibrotic stage:
- hypercellular marrow with granulocytes and megakaryocytes
- Megakaryocytes are large and weird and clustered
- Thrombocytosis in blood and sometimes neutrophilia
Progresses to fibrotic stage:
- reticulin (type 4 collagen) fibrosis in marrow –> hematopoiesis in marrow sinusoids
- leukoerythrobastosis - inc immature granulocytes and nuc RBCs and dacrocytes
- splenomegaly