ACUTE LYMPHOBLASTIC LEUKEMIA
LEUKEMIA
• Leukemia are the neoplastic proliferation of hemopoietic cells.
• Acute leukemias are defined as neoplsam • AML - more than 20 % blast• ALL- more than 25% blast.
ACUTE LYMPHOBLASTIC LEUKEMIA
• Commonest form of malignancy in childhood.• Peak incidence at 4 – 5 yrs of age.• Acute onset with short history of duration.• 85% are B cell , 15% are T cell.
PREDISPOSING FACTORS• HEREDITARY
• ACQUIRED• Ionizing radiations• Therapeutic radiations• Nuclear fallout• Diagnostic Xrays• Chemical agents• Viruses
MECHANISM OF LEUKAEMOGENESIS
• Activation of a proto-oncogene to an oncogene when it is translocated to a transcriptionally active site
• Formation of a chimeric transcription factor• Formation of a fusion protein with enhanced tyrosine
kinase activity• Activation of FTL3 receptor• Inactivation of tumour suppressor gene pathway
SYMPTOMS• FEVER • FATIGUE• BONE /JOINTS PAIN• WEIGHT LOSS• PURPURA AND BLEEDING MANIFESTATION• LYMPHADENOPATHY• HEPATOSPLENOMEGALY• STERNAL TENDERNESS• MEDIASTENAL MASS
FAB CLASSIFICATION• Based on morphology and cytochemistry.• stain AML ALL
MPO + -
SBB + -
NSE(non-specific esterase)
+ IN M4, M5 AND M7 -
PAS FINE + IN M6 , M7 + , BLOCK
ACID PHOSPHATASE - +, T ALL
FAB CLASSIFICATION
ALL L1 ALL L2 ALL L3
In childhood – L1 is the most common type In adults – L2 is the most common type
FAB classificationMorphology L1 L2 L3
1 Size of blast Small Large heterogeneous
Large homogenous
2 Cytoplasm Scanty Moderate Moderate, intensely basophilic
3 N/C Ratio High Lower Lower
4 Cytoplasmic vacuoles +/- +/- Prominent
5 Nuclear membrane Regular Irregular with clef ting
Regular
6 Nucleoli Invisible / indistinct
Prominent 1-2 Prominent 1-2
CRITICISM OF FAB CLASSIFICATION
1- It dose not include • Immunophenotyping• Cytogentics• Molecular characteristics2- immunological subtype of ALL3-biphenotypic leukemia4- Limited relevance to therapeutic or
prognostic implications.
WHO CLASSIFIACTION OF ALL (2008)
1-B lymphoblastic leukemia2- B lymphoblastic leukemia
9; 22) , BCR ABL1• t( v; 11q23) MLL rearangement• t (12;21) ETV6-RUNX1• With hypodiploidy• With hyperdiploidy• t (5;14) il3 –igh• t ( 1;19) E2A-PBX1 (tcf3-pbx1)3-T lymphoblastic leukemia/lymphoma
IMMUNOLOGICAL CLLASIFICATION
1- B ALL•PRO B ALL•EARLY PRE B ALL•PRE B ALL•MATURE B ALL2- T ALL3- MIXED LINEAGE ACUTE LEUKEMIA4-Undifferentiated acute leukemia
IMMUNOLOGICAL CLLASIFICATIONSUBTYPE HLA DR TdT CD 10 cIg smIg
Pro B ALL +_ + - - -
COMMON ALL + + + - -
Pre BALL + - - + -
Mature B ALL - - - - +
T ALL
• PAS negative acid phosphatase positive • CNS involvement and mediastenal mass• CD3 ,2 and 7 positive
Scoring system for biphenotypic leukemiaB lineage T lineage Myeloid
CD 79aCD 22.
CD 3 MPO
CD 10 CD 1 CD 13
TdT TdT, CD 7 CD 11bCD 11c
Uncommon variants of ALL
• Small cell variant- blast cells are small and may be mistaken for lymphocytes.
• Hand mirror variants- a subtype with cytoplasmic protrusion .
• ALL with eosinophilia• Granular cell ALL- The cells are large and
demonstrate azurophilic granulaes .
Hand mirror variants
DIAGNOSIS OF ACUTE LEUKEMIA
• Peripheral Blood smear• Bone marrow aspiration smear• Cytochemistry• Immunophenotyping• Cytogenetic analysis• Molecular genetic analysis
PERIPHERAL BLOOD EXAMINATION
• Total leucocyte count raised , normal or low.• Normocytic normochromic anaemia.• Thrombocytopenia.
• Subleukemic leukemia-Total leukocyte count is normal or low , but blast are seen in the peripheral blood.
• Aleukemic leukemia- Blast are not seen in the peripheral blood , but are demonstrable only in bone marrow.
BONE MARROW EXAMINATION
• Hypercellular• Normal hematopoietic elements diminished
ALL L1
Size – small.Cytoplasm scanty basophilic.N/C Ratio – high.Nuclear membrane – regular.
Nucleoli – invisible or indistinct.
BONE MARROW SMEAR
BLAST
ALL L2 Size of blast – large & heterogenous Cytoplasm – moderate N/C Ratio – lower Cytoplasmic vacuoles – variable Nuclear membrane – irregular with clefting Nucleoli – prominent ,1-2
BONE MARROW SMEAR
ALL L3 Size of blast – large & homogenous Cytoplasm – moderate & intensely basophilic N/C Ratio – lower Cytoplasmic vacuoles – prominent Nuclear membrane – regular Nucleoli – prominent , 1-2
BONE MARROW SMEAR
LYMPHOBLAST WITH CYTOPLASMIC VACUOLES & NUCLEOLI
STARRY SKY PATTERN
PAS STAIN
LYMPHOBLAST WITH BLOCK & COARSE GRANULAR STAINING
STAINS
METHYL GREEN PYRONINE OIL RED O(VACUOLES)
IMMUNOPHENOTYPING
• Diagnosis and classification.• Assessment of prognosis.• Monitoring of minimum residual disease.
Molecular Genetics-
• Establishment of lineage-DNA analysis.• Identification of translocation.• Detection of relapse.• Detection of minimum residual disease.
OTHER INVESTIGATIONS• Lumbar puncture.• Testicular biopsy.• X-Ray chest.
DIFFERENTIAL DIAGNOSIS• Leukemic phase of Non Hodgkins Lymphoma• Reactive lymphocytosis due to infections• Metastatic tumours in bone marrow• AML
ALL Vs AMLALL AML
Age Mainly children Mainly adults
Lymphadenopathy Usually present Usually absent
Hepatosplenomegaly +ve mild +ve mild
Gum hypertrophy -ve +ve in M4/M5
Skin infiltration -ve +ve in M4/M5
CNS involvement +ve in some +ve in some
Granulocytic sarcoma -ve +ve in few cases
Mediastinal mass +ve in T-ALL -
Associated DIC -ve +ve in M3
Serum muramidase Normal In M4/M5 (monocytic type)
Prognosis Good Bad
MorphologyLymphoblast Myeloblast Nuclear chromatin Coarse Fine
Nucleoli 1-2 3-5N:C ratio High HighAuer rod -ve +veAccompanying cells
Lymphocytes Myeloid precursor
Myelo peroxidase -ve +veSudan Black B -ve +vePAS stain Block positivity -ve in blast
AML ALL
PROGNOSTIC FACTORSFactor Good prognosis Bad prognosis
Race White Black
Age 2-8 yrs <1yr.,adult, >10 yrs
Sex Female Male
Meningeal involvement - +
Lymphadenopathy, liver, spleen
- Massively enlarged
Mediastinal mass - +
TLC <20x109 /L >50 x109 /L
Type of ALL L1 L2,L3
Cytogenetics Hyperdiploidy >50 chromosomes
Pseudodiploidy, t (4;11),t (9;22), BCR-ABL fusion m RNA, MLL-AF4 fusion mRNA.
Immuno-phenotype B-ALL,CD 10+, Early pre-B cell
T-ALL in children
Minimal residual disease detection
– ALL – B cell– Cd20/cd10/cd19/cd45– Cd9/cd34/cd19/cd45– Cd58/cd10/cd38/cd19– Cd20/cd10/cd19/cd34– ALL –T cell– TdT/CD5/CD3/CD7
• AML• CD34/CD33/HLA-DR/CD45• CD34/CD117/CD33/CD45• CD115/CD117/CD33/CD34• HLA-DR/CD117/CD33/CD34
• CLL• CD20/CD79a/CD19/CD5
Factors Predisposing to Childhood Leukemia
• GENETIC CONDITIONS Down syndrome
• Fanconi syndrome • Bloom syndrome • Diamond-Blackfan
anemia • Schwachman syndrome • Klinefelter syndrome • Turner syndrome
• Neurofibromatosis • Ataxia-telangiectasia • Severe combined
immune deficiency • Paroxysmal nocturnal
hemoglobinuria • Li-Fraumeni syndrome
• ENVIRONMENTAL FACTORS• Ionizing radiation • Drugs • Alkylating agents • Nitrosourea • Epipodophyllotoxin • Benzene exposure • Advanced maternal age