Leukaemia

Definition : Leukemia is a malignant disease of the hematopoietic system (blood forming cells).
Characterized by uncontrolled and abnormal proliferation of stem cells in the bone marrow.
And usually spill over into the peripheral blood.

Broad Classification
Depending on:
1. Aggressiveness of disease ; Acute Leukemias & Chronic Leukemias

2.Cell type - a) Myeloid b) Lymphoid

Acute Leukemias
Rapid onset
Very Aggressive
Cause death in weeks or months if not treated.

Chronic Leukemias
Less aggressive
slow in onset and progression
Causes death in months to years, if not treated.

Classification of Leukaemia

Myeloid
Acute myeloid leukemia (AML)

Chronic myeloid leukemia (CML )

Lymphoid
Acute lymphoblastic leukemia (ALL)

Chronic lymphoid leukemia (CLL)

Acute Leukemia
Unregulated and progressive proliferation with accumulation of immature, hematopoietic
precursors in the bone marrow (Blasts). The Blast count in the bone marrow is more than 20%.
Types of Blasts

Myeloblast

Lymphoblast
What are the differences between these two ?
Myeloblast Vs. Lymphoblast differences are in
Morphological features Cytoplasmic granules , Auer rods , nuclear features
Cytochemical features
Immunological features (immunophenotyping)

What are Auer rods ?

Auer rods are rod-shaped crystalloids made of primary granules.
Stain red purple with Leishman stain.
Stain intensely with myeloperoxidase (MPO) and Sudan Black B (SBB)
May be single or in clusters
If present, they prove that a blast is "myeloid" and not "lymphoid".

Morphological features
AML ALL
Myeloblast Lymphoblast

Cytoplasmic feature
Cytoplasmic + -
granules
Auer rods + -
Nuclear features
Chromatin Usually fine Condensed
Nucleolus Distinct, 2-3 1-2

Cytochemical features
Myeloperoxidase + -
Sudan Black B + -
PAS -ve or Block positive
diffuse positive
in erythroblasts (
AML M6)
FAB classification of acute Leukemias

FAB = French American and British

Based on
Morphology of blast cells

Cytochemical stains

In the FAB classification

1. Acute myeloid leukemia is classified in to EIGHT groups, M0 M7
depending on predominant cell line(granulocytic,monocytic,erythrocytic,megakaryocytic)
degree of cell differentiation

2. Acute lymphoid leukemia are divided into three groups, L1 to L3.

Depending upon cytologic features of blasts.

FAB classification of acute myeloid leukemia (AML M0-M7)

AML M0 (AML without differentiation)

-M0 to M3 involve myeloblast neutrophil series

-Myeloblasts without granules.
-No Cytochemical marker of Myeloblast.
-Some CD Marker may be positive

AML M1 (minimal differentiation without maturation)

-Very immature Myeloblasts

-Few granules or Auer Rods

AML M2 (Acute myeloblastic leukaemia with maturation)

-Myeloblasts & promyelocytes predominate;

-Auer Rods commonly present.
AML M3 (Acute Promyelocytic Leukaemia)

-Involves myeloblast neutrophil series , but maturation arrest at promyelocyte

-Myeloblasts and promyelocytes seen ;
-Promyelocytes are Hypergranular
-Many cells show many Auer Rods per single cell (Fagot cells)

AML M4 ( Acute Myelomonocytic Leukemia )

- Both myelo and monocytic differentiation

- Peripheral blood will show monocytosis
- Monoblats show : cytoplasm : abundant grey and
nucleus : nuclear groove , cleft and fold

AML M5 (Acute Monoblastic Leukemia )

AML M6 (erythroleukemia)

AML M7 (megakaryoblastic)
Acute myeloid leukemia
AML
Clinical Features
Common acute leukemia of adults.
Occasionally children are affected.
Signs and symptoms due to:

Suppression of normal Hematopoiesis (marrow failure)

Organ infiltration

Pallor
Bleeding gums

Ecchymotic patches
Infiltration of tissues/organs

enlargement of liver, spleen, lymph nodes

gum hypertrophy

bone pain

other organs: CNS, skin, testis, any organ

Lymphadenopathy
AML - Prognosis
Variable
60% complete remission with chemotherapy
Only 15-30% remain disease free after 5 years.
Lab findings
AML
Laboratory features

WBC usually elevated, but can be normal or low

blasts in peripheral blood

normocytic anemia

thrombocytopenia

DIC

> 30% blasts in bone marrow

Peripheral blood
RBCs : normocytic normochromic anemia
WBC :
Total leucocyte count (range 1000 to 1 lakh/cumm)
50% patients increased
50% patients normal or decreased count
Circulating blasts = Myeloblasts
Platelets: Reduced in number
Acute Myeloid Leukemia

Bone marrow in acute leukemia

necessary for diagnosis
 useful for determining type
useful for prognosis
Bone marrow findings
Bone marrow aspiration
Dry tap may be obtained (due to Hypercellular marrow)
biopsy will show sheets of blasts.

Successful aspiration

Bone marrow particles Hypercellular

Decrease in erythroid and megakaryocytic lines.

Blast count - > 30% of all nucleated cells (FAB criteria for diagnosis of Acute leukemia)

Bone marrow Biopsy

- Acute Myeloid leukemia
BM biopsy

Acute Lymphoblastic leukemia

ALL

Malignant proliferation of lymphoid stem cells.

The predominant cell in bone marrow and peripheral blood is a Lymphoblast.
The malignant lymphocytes replace normal hematopoietic tissue.
Infiltrate the lymph nodes, spleen, liver and other organs.
Clinical features
Age: common in childhood.
Peak incidence is between 2-5 years.
Signs and symptoms
Fatigue pallor due to anemia
Fever and repeated infection
Petechiae and hemorrhage due to thrombocytopenia
Bone pains due to marrow expansion.

Headache and vomiting CNS involvement

Hepatomegaly, Splenomegaly and lymphadenopathy due to infiltration.

Lymphadenopathy
Laboratory findings
Peripheral blood

RBC: normocytic normochromic anemia

WBC: count is usually increased but may be normal or decreased.

The circulating blasts are lymphoblasts.

Platelets: reduced in number.

Bone marrow

Hypercellular and shows >30% lymphoblasts.

All other cell lines are reduced in number.
ALL
Criteria for diagnosis
>30% blasts in the BM
Cytochemical stains
PAS Block positivity
MPO- Negative
TdT = Terminal deoxynucleotidyl tansferase positive

FAB classification of ALL

Three subtypes of ALL based on morphology of lymphoblasts.

ALL L1
ALL L2
ALL L3
ALL

ALL

ALL L1
most common in children
Best prognosis

ALL L2
Most common in adults

ALL L3
Rarest form of ALL
Occurs both in adults and children

ALL
Criteria for diagnosis
>30% blasts in the BM
ALL bone marrow biopsy
AML ALL
CHRONIC LEUKEMIAS

Insidious onset
Non specific complaints: wt loss or weakness
Accumulation of more differentiated elements
All stages of maturation present.
Predominance of more mature forms.
Progress slowly
Course of the disease in years

Types
Chronic Lymphocytic leukemia (CLL)
Chronic myeloid leukemia (CML).
Chronic myeloid leukemia
(CML)
Charachterized by:
Neoplastic growth of primarily myeloid cells in the BM.
Extreme increase in no. of leucocytes and its precursors in the peripheral blood.
CML is now considered as one of the myeloproliferative disorders.

Myeloproliferative disorder (MPD)

Group of disorder that results from:
neoplastic proliferation of one or more types of cellular elements
(erythroid, myeloid, megakaryocytes and fibroblasts)
Trilineage involvement is characteristic
One cell line more prominently affected than the other.

Classification of MPD
Phases in CML
Two Phases
Chronic phase
Blast crisis phase

Chronic phase
Initially patient are in Chronic phase
Respond well to therapy
Normal health restored and maintained for years.
Eventually 75% enter blast crisis phase
Blast crisis phase
Resembles Acute myeloid leukemia clinically and hematologically.
Prognosis is poor
Management is difficult
Survival is less than 6 months.
Pathophysiology of CML
Characteristic chromosomal abnormality
= Philadelphia chromosome (Ph)
Results from a reciprocal translocation between chromosome 9 and 22, t(9;22).

Philadelphia Chromosome (Ph)

Reciprocal translocation t(9;22)
Results in bcr/abl gene fusion
c-abl (Abelson) chromosome 9
bcr (break point cluster region)
chromosome 22
Fusion gene codes for a specific protein P210.
Protein with tyrosine kinase activity - plays critical role in pathogenesis

Clinical features
Age: Middle age ; peak 40-50 years
Sex : equal incidence in both sexes
Onset : insidious
Symptoms and signs
Weakness, loss of stamina, fever, weight loss
Fullness in abdomen/ dragging sensation in abdomen Due to massive Splenomegaly.
Bleeding from GIT, retinal hemorrhages.
Physical examination: pallor, splenomegaly, petichiae

Laboratory findings
Peripheral blood:
WBC:
Extreme leucocytosis.
WBC count: > 1lakh/c.mm.
Mean WBC count : 2-1.5 lakh/c.mm
Morphology:
Marked shift to left
Granulocytes in all stages of maturation
(myeloblasts, promyelocytes, myelocytes, metamyelocytes, band forms and segmented forms)
Predominant cell : segmented neutrophils and Myelocytes ( myelocyte peak)

Chronic phase :
Blast count < 10%
Accelerated phase:
Blast count up to 15%
Blast crisis phase:
More than 30%
Other WBCs
Increase in
Basophils, eosinophils, monocytes
 Progressive basophilia heralds blast crisis

Platelet:
> 50% cases marked thrombocytosis
Thrombocytopenia : in blast crisis phase
LAP score
Leukocyte alkaline phosphatase score:
Low or absent
Bone marrow
Hypercellular
Myeloid hyperplasia
ME ratio = 10:1 to 50:1
Erythropoiesis : decreased
Myelopoiesis: Cells in all stages of maturation
Blast less than 30% in chronic phase but > 30% in blast crisis phase
Megakaryocytes: increased in no.
Late stages : bone marrow shows fibrosis

Terminal phase or blast crisis

After 3-4 years of diagnosis of CML
Disease undergoes transition to accelerated phase which precedes the phase of blast crisis.
In the accelerated phase:
Hemoglobin falls <7gm/dl.
Increase in WBC count
Blast in peripheral blood >15%.
Basophil count >20%
Thrombocytopenia
Sudden increase in Splenomagaly
Bone marrow blast >10%
In blast crisis phase Marrow and Peripheral blast count > 30%
Clinically condition resembles acute leukemia
Survival about 1-2 months.
CML Peripheral smear
CML Basophilia
CML blast crisis
CML bone marrow aspirate
CML bone marrow biopsy
CML bone marrow biopsy
CML peripheral smear
CML peripheral smear
CML peripheral smear
Leukemoid reaction

Condition in which there is marked increase in WBC count with shift to left.
Seen in:
Infections
 Inflammatory disorders
Severe hemorrhage
Hemolytic states
The peripheral smear findings resemble findings in CML.
Therefore it is important to differentiate this condition from CML.
Differences between leukemoid reaction and CML

Chronic lymphocytic leukemia

CLL

A neoplastic (malignant) growth of primarily lymphoid cells characterized by :

Sustained proliferation of clonal,
well-differentiated lymphocytes in the peripheral blood and bone marrow

Absolute lymphocyte count >5,000/mm3

Usually >10,000/mm3

Affects older people (>50 years old)

Male predominance (M:F 2:1)

Clinical features
Age: exclusively a disease of adults.
Indolent, often asymptomatic
Fatigue, weight loss, anorexia
Autoimmune hemolytic anemia

Lymphadenopathy
CLL - Pathophysiology
Clonal B-cell neoplasm (>95% of cases)
Express mature B-cell markers
CD19, CD20,
Closely related to small lymphocytic lymphoma
Laboratory findings
Peripheral smear: The findings are diagnostic.
RBC: Normocytic normochromic
WBC:
High count 10,000 to 1,50000/c.mm
Absolute lymphocytosis
Lymphocytes: monotonous in appearance, round nucleus, clumped chromatin and scant blue
cytoplasm.
Smudge cells : due to rupture of fragile lymphocytes.
Peripheral smear -CLL
Bone Marrow
Hypercellular
Most of the cells are mature lymphocytes
Other cell lines are reduced

Bone Marrow - CLL

CLL - Natural History

Indolent, median survival 4-6 years
many CLL patients live >10 years
Progressive infiltration of organ systems
bone marrow, lymph nodes, liver, spleen
Progressive anemia and thrombocytopenia

Normal bone marrow

AML M0
(no maturation)
AML M1
(minimal maturation)
AML M1- MPO
AML M2 (WITH MATURATION)
AML M3 (promyelocytic)
AML M4 (myelomonocytic)
AML M5 (monoblastic)
AML M6 (erythroleukemia)
AML M7 (megakaryoblastic)

ALL
ALL
Criteria for diagnosis
>30% blasts in the BM
ALL bone marrow biopsy
Massive splenomegaly

Normal bone marrow

BM Biopsy -CML
Lymphadenopathy
Peripheral smear -CLL

Bone Marrow - CLL

Approach to Leukemias
Treatment of leukemias
SUMMARY

Acute Leukemia
accumulation of blasts in the marrow
Significance of adult acute leukemia
a hematologic urgency
usually fatal within weeks to months without chemotherapy
with treatment, high mortality due to disease or treatment-related complications (unlike childhood
acute leukemia)
notify Hematologist promptly if acute leukemia is suspected

How to distinguish AML vs CML

from looking at peripheral blood
Myeloid cell CML AML normal
blasts
promyelocytes
myelocytes
metamyelocytes
bands
neutrophils

Classification of acute leukemias

ALL
mainly children
M>F
curable in 70% of children
curable in minority of adults
AML
mainly adults
M>F

curable in minority of adults

Principles of leukemogenesis
a multistep process
neoplastic cell is a hematopoietic pleuripotent stem cell or early myeloid cell
dysregulation of cell growth and differentiation (associated with mutations)
proliferation of the leukemic clone with differentiation blocked at an early stage

Causes of acute leukemias

idiopathic (most)
underlying hematologic disorders
chemicals, drugs
ionizing radiation
viruses
hereditary/genetic conditions
Clincal manifestations
symptoms due to:
marrow failure
tissue infiltration
leukostasis
constitutional symptoms
other (DIC)
usually short duration of symptoms

Marrow failure
neutropenia: infections, sepsis
anemia: fatigue, pallor
thrombocytopenia: bleeding
Leukostasis
accumulation of blasts in microcirculation with impaired perfusion
lungs: hypoxemia, pulmonary infiltrates
CNS: stroke
only seen with WBC > 50 x 109/L
Constitutional symptoms
fever and sweats common
weight loss less common
Treatment of acute leukemias
Rx is influenced by:
type (AML vs ALL)
age
curative vs palliative intent
Principles of treatment
combination chemotherapy
first goal is complete remission
further Rx to prevent relapse
supportive medical care
transfusions, antibiotics, nutrition
psychosocial support
patient and family
Chemotherapy for acute leukemias
Phases of ALL treatment
induction
intensification
CNS prophylaxis
maintenance
AML treatment
induction
consolidation
Hematopoietic stem cell transplantation
permits rescue from otherwise excessively toxic treatment
 additional advantage of graft-vs-leukemia effect in allogeneic transplants
trade-off for allogeneic transplantation: greater anti-leukemic effect but more toxic
Prognosis
If you only remember 4 things from today, remember this:
acute leukemia = too many blasts in the marrow
2 broad categories: AML vs ALL
a hematologic urgency
prognosis is poor in adults; but good in kids with ALL.

Acute myeloid leukemia

Clinical features
Affect primarily adults (peak 15-39 yrs)
Findings related to anemia, neutropenia, and thrombocytopenia (fatigue, fever, spontaneous
bleeding)
Bleeding diathesis
Petichiae and ecchymoses and hemorrhages
DIC (AML M3)
Infections (oral cavity, skin, lungs etc.)

Signs and symptoms related to tissue infiltration

Less striking than ALL
Mild lymphadenopathy
Mild organomegaly
M4 and M5 infiltration of the skin and gingiva
CNS Involvement- less common
Localized masses
Myeloblastomas/granulocytic sarcomas/chloromas.
PROGNOSIS - AML
VARIABLE
60% COMPLETE REMISSION WITH CT
15-30% DISEASE FREE FOR 5 YEARS
ACUTE LYMPHOBLASTIC LEUKEMIA :ALL
GROUP OF NEOPLASMS COMPOSED OF IMMATURE,PRECURSOR B OR PRECURSOR T
LYMPHOCYTES (LYMPHOBLASTS).

MOST COMMON :PRE B CELL ALL

LYMPHOBLASTS
Condensed chromatin
Lack conspicuous nucleoli
Scant, agranular cytoplasm
Cytoplasm contains PAS (periodic acid Schiff ) positive material.
TdT positive
ALL-clinical features
Peak incidence: 4 years
Clinical features stem from accumulation of blast cells in the bone marrow.
Abrupt stormy onset
 Symptoms related to depression of normal marrow function.
Bone pain and tenderness
Generalized lymphadenopathy
Spenomegaly
Hepatomegaly
Testicular involvement
Central nervous system manifestations