Myeloid Neoplasm Flashcards
What are the three main categories of myeloid neoplasia?
- Acute myeloid leukemia (AML)
- Chronic myeloproliferative neoplasms (CMPN)
- myelodysplastic syndrome (MDS)
There is overlap between the categories. Ex. a myeloid neoplasm can have MDS and CMPN properties. In some cases CMPN and MDS can “transform” to AML.
What are the 5 terminally differentiated myeloid cells?
- neutrophils
- eosinophils
- basophils
- RBC
- platelets (even though they are not actual cells)
What is acute myeloid leukemia (AML)?
What is the proliferating cell?
What are the three things that occur as a result of the neoplasm?
It is the proliferation of immature cell forms (blasts) of the myeloid series resulting in:
- the replacement of normal bone marrow elements
- suppression of normal hematopoiesis
- circulation of neoplastic cells
What age group is typically affected by AML?
How do cases of AML arise?
AML affects adults (but can affect any age).
Most cases of AML are sporadic, but constitutional disorders with increased DNA fragility are at an increased risk.
How do most AML cases arise?
What are two situations when this is not the case?
Most AML cases are sporadic.
- Disorders that increase DNA fragility increase the risk
- DNA damaging agents (radiation, chemo alkylating agents and topoII inhibitors , smoking)
AML occurs due to genetic lesions that cause blasts that are ________ or show only _______________.
undifferentiated or show only early signs of differentiation
What are the two hits for the sporadic development of AML?
- first hit is a mutation in a gene encoding transcription factors necessary for normal maturation
- second hit is a new mutation in FLT3 tyr kinase receptor mutation that allows for increased cell proliferation
At present, what is the most valuable piece of information for predicting clinical outcome of AML?
the cytogenetic aberration detected at the time of diagnosis
How does AML present clinically?
Bone marrow infiltration causes:
- anemia- fatigue, pallor
- thrombocytopenia- bruising, petechial rash, mucousal bleeding
- Leukocytosis
What is crucial to obtain when working up patients with unexplained pancytopenia?
a bone marrow biopsy because sometimes blasts don’t make it to the peripheral smear.
What can complicate AML, particularly in cases of APML?
DIC
How is AML diagnoses?
Greater than or equal to 20% blasts in the blood or bone marrow.
Exceptions: Recurrent translocations can have less than 20% but have 1. t(8,21) 2. t(15,17) 3. inv(16)
What are the general morphological features of AML blasts?
Describe nuclear features and cytoplasmic features.
Myeloblasts have granulocytic differentiation.
Nuclear:
1. high N/C
2. dispersed chromatin
3. one–>multiple nucleoli
Cytoplasmic:
1. fine granules or crystalized granular material
2. Auer rods (specific for myeloid neoplasms)
3.Myeloperoxidase positive (MPO+)
Describe the morphology of a monoblast.
Monoblasts have more cytoplasm than myeloblasts and have greyer cytoplasm.
The nucleus is folded or round with lacy chromatin
What type of blast would be positive for MPO?
What type of blast would be positive for “nonspecific esterase”?
MPO = myelobast
non-specific esterase = monoblast
Describe the morphological appearance of megakaryoblasts.
They have round nuclei with one to three nucleoli and characteristic cytoplasmic blebs.
Immunophenotyping for myeloid lukemias can be done by what two techniques?
- immunohistochemical staining
2. flow cytometry
What are the lineage associated markers of myeloblasts?
CD117
CD13
CD33
MPO
What are the lineage associated markers of monoblasts?
CD14
What are the lineage associated markers of erythroids?
CD71
glycophorin-A
What are the markers of megakaryoblasts?
CD41 and CD61
What is CD34?
It is present on pluripotent hematopoietic stem cells and is considered a marker of immaturity
BLASTS
What is the difference between FAB classification of AML and WHO classification of AML?
FAB diagnosed AML on morphological appearance of the leukemic blasts.
WHO incorporates morphology with clinical and genetic information
AML with ___________ tend to respond well to therapy.
Balanced translocations (15,17) (8,21)