Hematologic Malignancies II Flashcards
What clinical microscopic finding is necessary for diagnosis of acute leukemia, but is not very well refined based on clinical course?
The rapid proliferation of blast clones found in the bone marrow or in peripheral blood.
Diagnostic criteria: >20% implies acute leukemia
Problem: (cut-off # is arbitrary)
Immunophenotyping (IDing a cell based on surface proteins with Abs) is helpful in Dx but has a limitation:
The problem with immunophenotyping by itself is that many leukemias (and other hematologic malignancies) break the rules – their immunophenotype appears to be mixed. So immunophenotype BY ITSELF did not provide us with a very good diagnostic system, although it is an essential PART of our current diagnostic workup.
Let’s play “Identify That Immunophenotype, Bro!”
CD34+
blasts
Let’s play “Identify That Immunophenotype, Bro!”
CD34+, CD33+
myeloid blasts
Let’s play “Identify That Immunophenotype, Bro!”
Tdt+, CD10+
lymphoid blasts
Let’s play “Identify That Immunophenotype, Bro!”
CD19+, CD20+
mature B-lymphocytes/lymphoma
Let’s play “Identify That Immunophenotype, Bro!”
CD3+, CD5+
mature T-lymphocytes/lymphoma
** remember, CD3+ is the TCR! **
Let’s play “ID That Cancer Based on the Genotype, Bro!”
PML-RARA
Then name the translocation!
AML subtype
t(15;17)
Let’s play “ID That Cancer Based on the Genotype, Bro!”
RUNX1-RUNXT1
Then name the translocation!
AML subtype
t(8;21)(q22;a22)
Let’s play “ID That Cancer Based on the Genotype, Bro!”
TEL-AML1 (ETV6-RUNX1)
Then name the translocation!
ALL subtype (I know, WTF assholes?!) t(12;21)(p13;q22)
Let's play "ID That Cancer Based on the Genotype, Bro!" FLT3 mutation (+)
AML subtype
Why is cytogenetics a better method for Dxing cancer?
Advantages:
Increased prognostic value
Predicts response to therapy
Identifies molecular targets for therapy development
Outline the current method for Dxing acute leukemias.
Basts > 20% in blood/bone marrow? Yes: acute leukemia No: cytogenetics Cytogen shows mutations/fusions of one of the 3 major types: acute leukemia No: something else
When Dx’d with acute leukemia, next step is detailed immunophenotype. May also require FISH or sequence-based studies.
List the 3 AML subtypes Dx’d by genetics alone, regardless of blast count.
RUNX1-RUNX1T1
CBFB-MYH11
t(15;17) PML-RARA (APL)
Explain how the PML-RARA subtype (APL) of AML causes cancer (responsible for 5-8% of AML cases) and what simple utility is used to send PML-RARA into clinical remission.
AML with t(15;17) PML-RARA (called APL) causes a dominant negative blockade of normal RARA that inhibits granulocyte differentiation.
PML-RARA itself can be blocked with a retinoic acid analog (all trans retinoic acid or ATRA)
ATRA induces differentiation of the blasts to granulocytes, CLINICAL REMISSION
How does t(15;17) PML-RARA (APL) present clinically?
Describe the morphology:
Describe the immunophenotype:
Prognosis?
clinical presentation: severe thrombocytopenia
Morph: Big blasts, cleaved “bat wing” nuclei, many cytoplasmic granules, auer rods in stacks.
Immuno: weak/absent CD34, HLA-DR
CD13+, CD33+
Prognosis is good if you make the Dx early.
How does t(8;21)(q22;a22) RUNX1-RUNX1T1 present clinically?
Describe the morphology:
Describe the immunophenotype:
Prognosis?
clinical presentation: younger pts, kids Morph: some maturation to myelocytes. Occasional crystallization of granule contents (auer rods) Immuno: CD34+, HLA-DR+, CD13+ CD33 weak Prognosis: good response to chemo
Describe the pathogenesis of t(8;21)(q22;a22) RUNX1-RUNX1T1.
5% of AML cases.
Fusion protein of 2 transcription factors (similar to PML). Runx1 is part of a heterodimeric transcription factor called Core binding factor (CBF)
Describe the pathophysiology of inv(16)(p13.1;q22) aka t(16;16)(p13.1;q22) CBFB-MYH11 How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
5-8% of AML cases
Path: Dominant negative repressor of myeloid maturation
CBFB is the other component of the CBF heterodimer!!
clinical presentation: younger pts, kids
Morphology: Mixed granulocyte-monocyte features (“Myelomonocytic”) Increased eosinophils in blood and marrow
Immunophenotype:
CD34+, CD117+ (blasts)
CD13+, CD33+ (granulocytes)
CD14+, CD11b+ (monocytes)
Prognosis: Better than most if “risk adapted” therapy is used
Acute myeloid leukemias that are well-characterized based on genetic subtyping make up only ___% of cases.
15-20%
AMLs with normal cytogenetics make up almost ___% of cases, and they trend toward these morphologic types:
50%
any morphologic type: granulocytes, monocytes, red cell precursors, megas
What determines how cytogenetically normal AMLs are treated?
depends on the results of targeted sequencing studies
How do cytogenetically normal AMLs present clinically?
Describe the morphology:
Describe the immunophenotype:
Prognosis?
Clinical Presentation: Any age group
Morphology: Undifferentiated, or variably granulocytic, or monocytic/monoblastic
Immunophenotype: Blast markers (CD34, CD117)+
typically CD33+
Prognosis: Depends on molecular genetics
The genes NPM1, FLT3, and CEBPA are significant in AML why?
the molecular findings in these cases are predictive of what kind of therapy they will respond to
How do AMLs with a complex karyotype present clinically? Describe their karyotype: Describe the morphology: Describe the immunophenotype: Prognosis?
AML with a complex karyotype (5-10% of AML cases)
Clinical Presentation: Any age group
Karyotype: three or more cytogenetic findings such as translocations, trisomies, or monosomies. These cases often show deletions or other mutations affecting TP53, conferring genetic instability.
Morphology: Undifferentiated, or variably granulocytic, or monocytic/monoblastic
Immunophenotype: Blast markers (CD34, CD117)+ typically CD33+
Prognosis: Poor
Time for some epidemiology:
Describe the clinical presentation of ALL. Who gets it? What is the prognosis in kids and adults?
Clinical Presentation: 75% of ALL cases occur in kids under 6 and over 80% of acute leukemias in kids are ALL
~80% cure rate in kids, ~50% in adults
Regarding ALL:
Does BCR-ABL1 carry a good or bad prognosis?
Bad
Regarding ALL:
Does MLL rearrangement carry a good or bad prognosis?
Bad
Regarding ALL:
Does TEL-AML1 (ETV6-RUNX1) carry a good or bad prognosis?
Good
Regarding ALL: Do hyperdiploid (>50 chromosomes) cases carry a good or bad prognosis?
Good
With regards to ALL: Describe the pathophysiology of TEL-AML1 (ETV6-RUNX1) How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: Fusion protein that acts as a dominant negative transcription factor with multiple effects on gene expression; in general THESE BLOCK MATURATION
Clinical presentation: kids. 25% of ped. B-ALL
Morph: big Agranular blasts
Immuno: **TdT+, **CD34+, **CD10+, CD20-
Prognosis: Good! 90% cure rate
With regards to ALL: Describe the pathophysiology of t(9;22) BCR-ABL1 How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: Fusion protein of part of a serine-threonine kinase (BCR) to a tyrosine kinase (ABL1). PROLIFERATION ACTIVATOR. IKZF1 transcription factor mutated in 84% of cases DIFFERENTIATION INHIBITOR
Clinical presentation: Older adults (25% of ALL cases) Kids < 1yo (2-4% of peds ALL)
Morph: big Agranular blasts
Immuno: CD10+, **CD19+, TdT+
Prognosis: Poor
With regards to ALL: Describe the pathophysiology of an MLL rearrangement How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: Fusion of a transcription regulator (histone methyl transferase) to any of severa; partners. INHIBITS DIFFERENTIATION (also found in AML)
FLT3 mutations in 20% of cases (ENHANCES PROLIFERATION)
Clinical presentation: Most common leukemia in kids < 1yo
Morph: big Agranular blasts
Immuno: CD10-, CD19+, TdT+
Prognosis: Poor
With regards to ALL: Describe the pathophysiology of T-ALL How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: most have a translocation of an oncogene to a T-cell receptor promotor (any of the three TCR loci in the genome). Multiple possible partners.
** COMMON MOTIF FOR LYMPHOID MALIGNANCIES, ONCOGENE TRANSLOCATION TO AN Ig or TCR Promotor **
Clinical presentation: Kids. 25% of peds B-ALL. Often with thymic mass or lymph node, spleen involvement.
Morph: big Agranular blasts
Immuno: TdT+, CD3+, CD5+; can express myeloid or B-cell antigens as well
Prognosis: “high risk” require aggressive chemo, results in survival rate comparable to that of kids with B-ALL.
We need to be able to recognize an ALL case from the:
We need to be able to recognize whether an ALL case is good or bad (prognosis) based on:
immunophenotype; genotype
What is the double hit that makes t(9;22) cases especially nasty players?
9;22 cases have taken two particular genetic hits, one that BLOCKS MATURATION and another that ENHANCES PROLIFERATION
T-cell ALL’s lack expression of B-cell markers:
B-cell ALL’s lack expression of T-cell markers:
Both express:
CD20, CD10
CD3, CD5
TdT (reminder: Terminal deoxynucleotidyl transferase (TdT) is a specialized DNA polymerase expressed in immature, pre-B, pre-T lymphoid cells, and acute lymphoblastic leukemia/lymphoma cells. TdT adds N-nucleotides to the V,D, and J exons during antibody gene recombination, enabling the phenomenon of junctional diversity)
There are 3 malignancies arising in the bone marrow, these are called myeloproliferative diseases. Name the 3 lineages that give rise to them.
Myeloid, erythroid, megakaryocyte derived types
Whereas rapid proliferation of blast clones are indicative of acute leukemias, you will find what in myeloproliferative diseases?
Chronically proliferating clones which differentiate to circulating blood cells.
What is the prototype cancer subtype for myeloproliferative disease?
Chronic myelogenous leukemia (CML)
What cell lineage does CML derive from?
myeloid
What cancer subtype shares both myeloproliferative and myelodysplastic features?
chronic myelomonocytic leukemia (CMML)
CML has these characteristic cellular types found in the blood:
High WBC
All stages of granulocyte maturation end up in the blood.
(Myeloblasts, promyelocytes, myelocytes, metamyelocytes, bands, and immature eos and basos)
CMML has these characteristic cellular types found in the blood:
High WBC
Monocytes, promonocytes,
Weird hybrids between monocytes and granulocytes
Name the two types of myeloproliferative neoplasia presenting with an elevated eosinophil count.
Chronic eosinophilic leukemia (CEL) and PDGFR neoplasm
Is neoplasia of mature neutrophils common or rare?
Very rare. We will not speak of this further.
Where does mastocytosis present?
Often outside the bone marrow and lymph nodes, but in most cases the bone marrow is involved
Erythroid and Megakaryocyte lineage neoplasia often present with:
Thrombosis.
Overproduction of erythroid line cells is called:
Polycythemia vera
Overproduction of Megakaryocyte line cells is called:
essential thrombocythaemia or primary myelofibrosis
When should you suspect that a myeloproliferative disease is present?
When there are high numbers of immature granulocytes (more myelocytes than metamyelocytes) present in circulation and there are no symptoms of infection or frank sepsis (such as toxic granulation).
Looking at a slide of bone marrow aspirate from a pt with CML, you expect to see:
hypercellularity with many myeloid precursors, little in the way of dysplasia, and no increase in blasts.
You are more likely to make a Dx of CML by ordering these tests:
Real-time PCR (RT-PCR)* assay for the BCR-ABL1 fusion protein, using peripheral blood.
*RT-PCR amplifies DNA and simultaneously identifies presence of targeted DNA as cycles progress
How do we now detect if treatment for CML is sending a pt into remission?
whether the fusion transcript (oncogene) is detectable by RT-PCR (a “complete molecular response.”)
Why is it so important to catch CML early on?
f you miss the diagnosis, or let the condition slip by for a year or two before making the diagnosis, you increase the risk that the patient will progress to an acute leukemia.
What are the basic steps in Dxing CML?
Pt presents w/ symptoms > CBC + manual count/differential > suspect CML > RT-PCR of peripheral blood sample for BCR-ABL1 > bone marrow biopsy
Describe the pathophysiology of polycythemia vera How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: myeloproliferative disease resulting in increased red cell count. Activated Jak2 mutations in >95% of cases - detectable in peripheral blood leukocytes. Some pts have mutations in the EPO receptor instead (Mpl)
Clinical presentation: Thrombosis/hypertension/stroke of MI. Increased RBCs can also be due to lung disease
Morph: Hypercellular marrow, erythroid hyperplasia, increased Megs
Immuno: No known features
Prognosis: > 10 yr survival is common; can progress to myelofibrosis, MDS, acute leukemia
Describe the pathophysiology of essential thrombocythemia How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: Pathogenesis poorly understood. Activated Jak2 mutations in ~50% of cases - detectable in peripheral blood leukocytes. Mutations in another gene (calreticulin) occur in ~25% 10 yr survival is common; can progress to myelofibrosis, MDS, acute leukemia
Clinical presentation: Thrombosis
Morph: Increased Megakaryocytes; they’re large and weird looking, even for Megs. Tend to cluster. Oddly, megs have one nucleus 10 yr survival is common, can cprogress to myelofibrosis, MDS, acute leukemia.
A reticulin stain on a peripheral blood smear, showing more reticulin fibers, is indicative of what?
Fibrosis, possibly primary myelofibrosis.
more found in PM than ET
Describe the pathophysiology of primary myelofibrosis How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: Jak2 mutations in ~50% of cases - detectable in peripheral blood leukocytes.
Clinical presentation: Thrombosis
Morph: increased Megs; bizzare shapes, clustering; fibrosis
Immuno: No known features
Prognosis: usually shorter survival than ET; can progress to marrow failure, acute leukemia
Neoplasms of mast cells usually present as:
benign cutaneous lesions in kids (the most common is urticaria pigmentosa”, aka itchy pigmented skin lesions)
Usually don’t spread beyond the skin.
But when they do:
they release lots of histamine and other mediators, causing systemic symptoms (flushing, abdominal pain, tachycardia, hypotension) that can can really confuse the clinician.
The bone marrow is the most common site of systemic involvement, but multiple organs (lymph nodes, spleen, liver) can be involved
A test for a certain enzyme, ______ , can help you in a Dx of mastocytosis. Although this is also present in hyperactive normal mast cells.
tryptase
Describe the pathophysiology of mastocytosis How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: Bland looking cells, round or spindle shaped
30% are associated with a second hematologic malignancy
Genetics: Either cKIT mutants OR PDGFRA activation (FIP1 translocation)
Clinical presentation: Variable and confusing Non-blast cells can proliferate in the bone marrow, shit gets confusing from there.
Morph: Aggregates of bland looking cells, round or spindle shaped, sometimes with eosinophilia
Immuno: Tryptase, CD117 (C-KIT, the SCF receptor!), CD25 usually positive count on these for DX!!
Prognosis: Highly variable, depends on a complex subclassification scheme
If you suspect that a high WBC count, of any lineage, may be neoplastic rather than reactive to inflammation/ infection, you should:
get molecular testing done (immunophenotyping, genotyping)
When you think poorly functioning clones of WBCs, think:
myelodysplasia! (myelodysplastic syndrome {MDS})
When discussing phenotypes, genotypes, and immunostaining of myelodysplasias, clinicians and scientists alike use the phrase:
“Shit’s just fucked up”
What are some key Dx features of myelodysplasias?
Abnormal “dyspoietic” bone marrow morph
Abnormal “dyspoietic” immunophenotypes of maturing precursors
Abnormal cytogenetics
Increased morphologic blasts (> 5%, < 20 %)
What demographic are myeodysplasias commonly found in?
Old people.
For some of them the condition does not seem to affect actuarial survival – meaning that in some cases our therapies will harm rather than help. But for others, there are effective drugs.
List the 5 major adult forms of myelodysplasia:
5 major adult forms (best to worst prognosis)
Refractory cytopenia with unilineage dyplasia
Refractory anemia with ring sideroblasts
Myelodysplastic syndrome with isolated del(5q)
Refractory cytopenia with multilineage dysplasia
Refractory anemia with excess blasts
Describe the pathophysiology of refractory cytopenia with unilineage dysplasia How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: Non-specific cytogenetic abnormalities (trisomies, monosomies) may be present
Clinical presentation: unexplained cytopenia(s), usually elderly pts (>65 yo)
Morph: Weird looking precursors; binucleation or irregular nuclei; can show fibrosis, high or low cellularity, megaloblastoid features.
Immuno: can show abnormal acquisition of surface markers
Prognosis: Survival not clearly less than normal for age; rarely progress to AML
Describe the pathophysiology of refractory anemia with ring sideroblasts How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: Non-specific cytogenetic abnormalities (trisomies, monosomies) may be present
Clinical presentation: unexplained cytopenia(s), usually elderly pts (>65 yo)
Morph: Ring sideroblasts, usually with dyspoietic features (in red cell series only)
Immuno: can show abnormal acquisition of surface markers
Prognosis: Survival not clearly less than normal for age; rarely progress to AML
Describe the pathophysiology of myelodysplastic syndrome (MDS) with isolated del(5q) How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: all the megakaryocytes are mononuclear; cytogenetics shows only loss of the large arm of Chr 5
Clinical presentation: Anemia, often severe usually elderly pts (>65 yo), more often women
Morph: **all the megs are mononuclear **
Immuno: No known findings
Prognosis: Good median survival; treatable with lenalidomide; 10% progress to AML
FOCUS ON CYTOGENETICS AND MORPHOLOGY FOR DX
Describe the pathophysiology of multilineage dysplasia How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: Anemia, often severe; usually elderly pts (>65 yo), more often women
Clinical presentation: granulocytes (if affected) don’t granulate normally; nuclei don’t lobulate normally
Immuno: can show abnormal acquisition of surface markers
Prognosis: Median survival 30 months; 10% progress to AML in 2 years
Describe the pathophysiology of refractory anemia with excess blasts How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: 5% - 9% morphologic blasts (RAEB-1)
10% - 19% morphologic blasts (RAEB-2)
About half show nonspecific cytogenetic abnormalities
Clinical presentation: Cytopenias; usually elderly patients (>65 yrs)
Morphology: Blasts and dyspoietic maturation
Immunophenotype: Blast population (CD34+, and/or CD117+) usually evident
Prognosis:
RAEB-1: 25% progress to AML.
RAEB-2: 33% progress to AML.
A pt with pancytopenia has 26% blasts in his bone marrow. Is this an acute leukemia? What’s the next test you will perform?
YES. Above 20% blasts in marrow of peripheral blood = acute leukemia every time! Next test: determine the subtype via immunophenotyping or sequence based studies.
A pt with pancytopenia has 12% blasts in his bone marrow. Is this an acute leukemia?
Depends on the cytogenetics
A six year old kid presents to the ER with a WBC count of 230 K/uL. What's the most likely Dx of the following options? AML Sepsis CML ALL polycythemia vera
ALL Most common acute leukemias in kids are lymphoblastic 75% of ALL cases occur in kids under 6yo 80% cure rate in kids 50% cure rate in adults
A CD33+ cell is probably myeloid or lymphoid in origin?
Myeloid
A mutation in FLT3 (tyrosine kinase) would inhibit differentiation or promote proliferation?
Promote proliferation
Which of the following immunophenotypes is consistent with ALL? CD10+, TdT+ CD34+, CD33+ CD117+, CD11b+ HLA-DR+, CD33 weak CD34-, CD33-, CD117 weak
CD10+, TdT+
Leukemic blasts in a 5yo are TdT+, CD3+, CD5+, and show the following translocation: t(14q11;10q24)(TCR-alpha;HOX11). Where outside the bone marrow would you expect these cells to form a mass? Options: Lung Skin Brain Testes Thymus
Thymus
CD3+ and CD5+ tell you these are T-cells. T-cells mature in the thymus. The mass will form in the thymus, most likely.
Your pt has a clone of cells in his bone marrow with a constitutively activated mutation in Mpl (the TPO receptor). What clinical finding do you expect, of the following? Neutrophilia Thrombocytosis Erythrocytosis Acute myeloid leukemia Myelodysplasia
Thrombocytosis
What is the gene fusion most commonly associated with polycythemia vera? (in this case, consititutive activation of EPO receptor)
Jak2-V617F mutation
A 49 yo woman has a platelet count of 635 K/uL (normal 150-400). She is also anemic (Hb 9, normal 12-16) and microcytic (MCV 72, normal 80-100). What’s the next study you need from the lab?
Fe studies (ferritin, serum Fe, TIBC) The first thing you look for is a reactive or non-malignant condition. Once you have ruled that out, then you can look for a neoplastic cause of the symptoms. Remember, Fe deficiency, infection, and inflammation can cause elevated platelets.
65 yo man with myelodysplasia (refractory anemia with multilineage dysplasia). His WBC, Hb, and platelet cound have all been steadily dropping over the past 6 months. What's the most important thing to rule out of the following? Progression to CML Progression to ALL Progression to AML Myelofibrosis B12 and/or folate deficiency
Progression to AML.
You would have noticed and managed B12 and/or folate def. 6 months ago when you Dx’d the anemia.
CML wouldn’t present this way.
ALL is most common in kids.
Melofibrosis, although more likely, isn’t the most important of the remaining two to rule out first.
