WBC: Lecture 4 Myelodysplastic syndromes, acute leukemias

A: Moderate Aplastic Anemia.

A: Severe Aplastic Anemia.

A: Very Severe Aplastic Anemia.

A: Bone marrow cellularity < 25% plus at least two of the following:
Neutrophils 0.2–0.5 × 10⁹/L
Platelets < 20 × 10⁹/L
Reticulocytes < 20 × 10⁹/L or < 1% corrected for Hct

A: Same as SAA, but neutrophils < 0.2 × 10⁹/L.

A: The lower the neutrophil count, the more severe the aplastic anemia (MAA > SAA > VSAA).

A: Pancytopenia — reduced RBCs, WBCs, and platelets.

Very typical case on aplastic anemia
Low WBCs
Low HGB - ANEMIA
MCV - macrocytosis.

Platelets - low!!!! KEY severe thrombocytopenia
WBCs (neutrophils and lymphocytes) are affects. LOW in count.

Reticulocytes – absolute value is low but it can be inaccurate sooooo calculate for RPI.

APLASTIC ANEMIA;

STEM CELL DISORDER can develop aplastic anemia ( there is a link to these diagnosis)
PNH can also present with pancytopenia and hemolysis, often overlapping with aplastic anemia. PNH screening is part of the differential diagnosis for acquired bone marrow failure syndromes.

If we detect blasts, it pushes towards AML !!!

SAA

A: Myelodysplastic Syndromes.

acquired clonal hematopoietic disorders;

somatic gene mutation at the HSC level !

A: Progressive cytopenias due to defective maturation of erythroid, myeloid, AND megakaryocytic cell lines.

A: Abnormal or defective cell development in each hematopoietic cell line.

A: Development into acute myeloid leukemia (AML).

A: 76 years old.

A:
Older age (above 65)
Inherited bone marrow failure syndromes

Fanconi anemia, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome

A: Abnormal development or maturation of red blood cells (RBCs) in the bone marrow.

A: Oval macrocytes.

A: Small RBCs with decreased hemoglobin (pale color), found in peripheral blood.

A: The presence of two distinct RBC populations in the same sample — one normal and one abnormal in size or color.

- RBC precursors with more than one nucleus
- RBC precursors with abnormal nuclear shapes
- RBC precursors with uneven cytoplasmic staining
- Ring sideroblasts

A: It indicates abnormal erythroid maturation — a hallmark of dyserythropoiesis.

A: It shows defective maturation of the nucleus during erythropoiesis.

A: Abnormal hemoglobin synthesis or uneven maturation of the cytoplasm.

A: RBC precursors in the bone marrow that contain iron-loaded mitochondria forming a ring around the nucleus (visible with Prussian blue stain).

A: Ineffective erythropoiesis and abnormal iron utilization within developing RBCs.

A: Abnormal development or maturation of myeloid cells (granulocytes) in the bone marrow or peripheral blood.

- Persistence of basophilia in the cytoplasm of otherwise mature white blood cells (WBCs), indicating nuclear-cytoplasmic asynchrony
- Agranular or hypogranular neuts
- Hyposegmentation, hypersegmentation, nuclear rings

A: Nuclear-cytoplasmic asynchrony — meaning the nucleus and cytoplasm are maturing at different rates.

- N:C asynchrony
- Uneven basophilia of the cytoplasm
- Abnormal cytoplasmic granulation (pro or myelo or both may lack granules)
- Agranular pro may be mistaken for a blast
- Hyposegmentation, hypersegmentation

PB
- Giant PLTs
- Micromegakaryocytes
- Agranular or hypogranular PLTs
BM
- Large mononuclear megakaryocytes
- Bilobed nuclei, or multiple small, separated nuclei

The decrease in neutrophil side scatter shows that when neutrophils lose their granules, they start to overlap with the monocyte area. In the normal (control) sample, neutrophils and monocytes are clearly separated.

A: It analyzes surface markers on neutrophils to assess for abnormal antigen expression.

A: A large proportion of granulocytes (neutrophils) abnormally express CD64.

A: CD64 is an antigen typically found on immature myeloid or monocyte cells.

A: It suggests abnormal or immature granulocyte maturation — a sign of dysplasia or myelodysplastic changes.

Anemia in >85% cases,
high MCV, poikilo (oval, elliptical, teardrop, spheres, and fragmented cells),
neutropenia, neutrophil hypogranularity, acquired PH (pelger huit), Ring-shaped nuclei in neuts, mild to moderate thrombocytopenia, large PLTs with poor granulation,
prolonged PFA-100.

Serum iron/transferrin/ferritin/LDH and uric acid elevated.

Mostly hypercellular in one or more lines, with dysplasia.

A: Anemia, or infection, or petechiae (depending on the lineage involved), <1% blasts in PB and <5% in BM.

A: More than one lineage is dyspoietic, <1% blasts in PB and <5% in BM.

A: SF3B1 gene (spliceosome) mutation, this mutation + at least 5% ring sideroblasts, dimorphic RBC picture on PBS (combination of hypochromic and normochromic cells).

A: Trilineage cytopenia, two types according to WHO.

MDS-EB1: 5% to 9% blasts in the bone marrow or 2% to 4% blasts in the peripheral blood.

MDS-EB2: 10% to 19% blasts in the bone marrow and 5% to 19% blasts in the peripheral blood, Auer rods, more aggressive and higher risk of transformation into AML

A: Affects predominantly women and occurring at a median age of 70. Patients have anemia without other cytopenias.

A: MDS that does not fit into other defined subtypes.

a. Dyspoiesis

b. Target cells

c. Vitamin B12 and folate levels

- Vitamin B12 and folate level testing. (megaloblastic picture)

- Myelodysplastic anemia (1:1 = erythropoiesis )

- MDS with ring sideroblasts (MDS-RS)

considered only morphology and cytochemical stains, required at least 30% blasts for diagnosis

more informative, considers clinical features, morphology, immunophenotyping, cytogenetics, and molecular genetics

Knowing this helps with treatment and patient outcome of the treatment.

Hyperdiploidy is the presence of more than the normal number of chromosomes in a cell, while hypodiploidy is the presence of fewer than the normal number of chromosomes

They show less specificity and less correlation with prognosis and treatment outcome than in B-ALL.

t(9;22) -> BCR-ABL1 — Philadelphia chromosome positive, more common in adults, responds to imatinib (Gleevec).

t(v;11q23.3); KMT2A (MLL) rearranged — has a very poor prognosis.

t(12;21) -> TEL-AML1 (ETV6-RUNX1) — rare in adults, excellent prognosis in children.

B-lymphoblastic leukemia/lymphoma with hyperdiploidy — less common in adults, favorable prognosis in children.

B-lymphoblastic leukemia/lymphoma with hypodiploidy — poor prognosis in both children and adults.

Left: ALL
Right: AML

Small blasts with a thin rim of cytoplasm.

Blasts show irregular clefts or indentations of the nucleus.

Blasts show prominent cytoplasmic vacuolations - which are lipid contained vaculoes caused by EBV.

CD34, CD19, cytoplasmic CD22, TdT

CD34, CD19, CD10, cytoplasmic CD22, TdT

CD19, cytoplasmic CD22, cytoplasmic μ, variable TdT

CD2, CD3, CD4, CD5, CD7, CD8, TdT

Most often in teenaged males

Presents with mediastinal mass, elevated peripheral blast counts, meningeal involvement, and extra marrow infiltration

CD2, CD3, CD4, CD5, CD7, CD8

TdT – Terminal deoxynucleotidyl transferase

Acute Lymphoblastic Leukemia (ALL) — blasts are large and pleomorphic with prominent nucleoli and cytoplasmic projections (hand mirror forms).

The plots show blasts positive for CD34, CD10, and TdT, but negative for cytoplasmic CD79a.

Intermediate (common) B-ALL: CD34, CD19, CD10, cytoplasmic CD22, TdT

Blasts are positive for CD2, CD3 (cytoplasmic), CD7, and CD34.
➡️ This immunophenotype supports T-lymphoblastic leukemia/lymphoma (T-ALL).

T-cell lineage — cCD3 is a specific marker for immature T-cells.

CD34 expression indicates blast immaturity (an early precursor T-cell stage).

Acute Myeloid Leukemia (AML) — most common in adults, less common in children.

Morphology of the blasts.

Molecular genetics and cytogenetics.

No, the clinical picture is not specific.

Common signs: pallor, fever, easy bruising, splenomegaly (in ~50% of patients), risk of DIC, skin and gum infiltration.
Lymphadenopathy is rare.

Over 90% of patients show blasts in PB.

Usually 5–30 × 10³/µL, but it can vary.

Anemia and thrombocytopenia (always present)

Neutropenia (WBC may be normal)

Bone marrow hypercellular with >20% blasts (diagnostic threshold with supporting genetics)

Hyperuricemia

Hyperphosphatemia

Hypocalcemia

Risk of acute renal failure and tumor lysis syndrome (especially with very high WBC counts)

AML with t(8;21) -> RUNX1-RUNX1T1
AML with inv(16)or t(16;16)-> CBFB-MYH11
APL with PML-RARA
AML with t(9;11) -> KMT2A(MLL)-MLLT3
AML with mutated NPM1
AML with biallelic mutation of CEBPA
AML with mutated RUNX1

AML with mutated NPM1 (nucleophosmin).

AML with biallelic mutation of CEBPA.

AML with mutated RUNX1.

RUNX1: Runt-related transcription factor 1

MYH11: Smooth muscle myosin heavy chain 11

CBFB: Core binding factor beta

MLL/KMT2A: Lysine methyltransferase 2A (multi-lineage leukemia gene)

RARA: Retinoic acid receptor alpha

PML: Promyelocytic leukemia gene

Acute myeloid leukemia, minimally differentiated

Acute myeloid leukemia without maturation

Acute myeloid leukemia with maturation

Acute promyelocytic leukemia (APL)

Acute myelomonocytic leukemia

Acute myelomonocytic leukemia with eosinophilia

Acute monocytic leukemia, poorly differentiated

Acute monocytic leukemia, well differentiated

Acute erythroleukemia

Acute megakaryocytic leukemia

About 5% of AML cases.

Children and young adults — this subtype is most common in these age groups.

Dysplastic granular cytoplasm

Auer rods

Some maturation (similar to FAB M2 phenotype)

Pseudo–Pelger-Huët cells

Hypogranulation

Possible eosinophilia

Diagnosis is based on the genetic abnormality (t(8;21)), regardless of blast count.

Occurs in 5–8% of AML cases.

Myeloblasts, monoblasts, and promyelocytes in both peripheral blood and bone marrow.

Eosinophilia with dysplastic changes in the bone marrow.

CNS involvement (central nervous system relapse).

The genetic abnormality itself is sufficient for diagnosis, regardless of blast count.

t(15;17) translocation involving PML-RARA.

5–10% of AML cases.

At the promyelocyte (pro) stage.

Abnormal hypergranular promyelocytes, some containing Auer rods (often seen in bundles called “faggot cells”).

Disseminated Intravascular Coagulation (DIC) — caused by release of procoagulant from promyelocytes.

Seen in 30–40% of APL cases; the cells have fewer granules and may be mistaken for other AML types.

Detection of the t(15;17) translocation — sufficient for diagnosis regardless of blast count.

All-trans-retinoic acid (ATRA) and arsenic trioxide;

Mechanism: ATRA induces differentiation of promyelocytes.

About 6% of AML cases.

Monoblasts and immature monocytes are increased.

Blasts are large with abundant cytoplasm and fine nuclear chromatin.

Blasts may have pseudopodia, granules, and vacuoles.

Occurs typically in children and may involve skin or gum infiltration.

Acute Myeloid Leukemia, Minimally Differentiated

Both MPO and SBB are negative.

Less than 5% of AML cases.

Infants or older patients.

It shows minimal differentiation — blasts lack clear evidence of maturation.

Acute Myeloid Leukemia Without Maturation

MPO and SBB are positive in about 3% of blasts.

About 90% of non-erythroid cells in the bone marrow are blasts.

Less than 10% of cells show maturation, up to the promyelocyte stage.

AML M1 shows some evidence of myeloid differentiation (MPO/SBB positive), while AML M0 is minimally differentiated (MPO/SBB negative).

Acute Myeloid Leukemia with Maturation

More than 20% blasts in the bone marrow.

More than 10% of cells show neutrophilic maturation.

Less than 10% of blasts are of monocytic lineage.

CD36, CD14, CD64

Acute Promyelocytic Leukemia (APL)

At the promyelocyte (pro) stage.

t(15;17) — the PML-RARA translocation.

CD13+, CD33+, CD64+

CD34-, CD11b-, HLA-DR-

Hypergranular promyelocytes and “faggot cells” (bundles of Auer rods).

Acute Myelomonocytic Leukemia (AMMoL)

Very high WBC count.

Monocytic cells (monoblasts and promonocytes) and neutrophilic cells.

Myeloid and monocytic lineages.

Presence of monoblasts and promonocytes alongside neutrophilic precursors.

Acute Monoblastic/Monocytic Leukemia (AMoL)

More than 80% of cells are of monocytic origin.

M5a (Acute Monoblastic Leukemia): monoblasts predominate

M5b (Acute Monocytic Leukemia): promonocytes predominate

Acute Erythroid Leukemia (Pure Erythroid Type)

More than 80% of cells are erythroid in origin.

More than 30% are pro-normoblasts.

Multinucleation

Nuclear-cytoplasmic asynchrony

Vacuolization

More than 50% are nucleated red blood cells (nRBCs).

Ring sideroblasts

Howell–Jolly bodies

Periodic Acid–Schiff (PAS) — positive in erythroid precursors.

Aggressive and rapid progression.

Acute Megakaryocytic Leukemia (AMKL)

More than 50% of blasts must be of megakaryocytic origin.

Megakaryoblasts and micromegakaryocytes (small, immature megakaryocytes).

Giant or dysplastic platelets

Cytoplasmic blebs on blasts

May show pancytopenia

AMML

CD34 positive cells — representing hematopoietic blasts or immature precursor cells.

Myeloblasts (blue)

Monoblasts (red)

CD34+, MPO+, CD2+

CD14+, CD64+, CD2+

Both myeloblasts and monoblasts express CD2, a T-cell–associated marker that can appear aberrantly (or abnormally) in AML M4, Eo

M4 Eosinophilic AML (M4 Eo)

AML

A primitive MPO– (myeloperoxidase negative) myeloblast population.

CD34+, TdT+, CD38+, with a subpopulation positive for CD56.

CD7, a T-cell marker aberrantly expressed in AML blasts.

Because the blasts are MPO negative, indicating minimal myeloid differentiation despite myeloid antigen expression.

It’s associated with poor prognosis and increased blast immaturity.

Immature (primitive) blast cells, as TdT is a marker of early progenitor cells.