Infantile leukemia

1. Pediatric AML including myeloid
proliferation in Downs syndrome,
Infantile acute leukemias, and
childhood MDS
P.Rajaguru
Dr. Shano Naseem

2. Pediatric AML

3. Pediatric AML
• Less common in pediatric population than
adults. More common in adolescence and a
peak during the neonatal period.

4. Clinical presentation
• Variable
• Hyperleukocytosis
• Organomegaly
• Respiratory distress
• 25-30% develop skin lesions (Leukemia Cutis)
– 50% of cases are initial sign
– 10% of cases occur in the setting of normal BM
• CNS involvement
• lymphadenopathy

5. Predisposing Factors
Inherited Predisposition Syndromes
• Inherited Marrow Failure and Chromosome Instability Syndromes:
Fanconi anemia, dyskeratosis congenita, bloom syndrome, ataxia
telangiectasia.
• Defects in Genes Regulating Differentiation and Cell Proliferation
Pathways:
1) Congenital amegakaryocytic thrombocytopenia- inherited
mutations in the thrombopoietin receptor (c-mpl),
2) familial platelet disorder -CFFA2,
3) Severe congenital neutropenia (Kostmann syndrome)- treated with
G-CSF,
4) Shwachman-Diamond syndrome,

6. 5) Diamond-Blackfan anemia –RPS 19,
6) Neurofibromatosis type 1 and Noonan syndrome activation of the
RAS gene pathways. Germline mutations of PTPN11 have been
shown to lead to Noonan syndrome and JMML.
• Twins and Familial Cases: Transplacental transfer. Transmission
rates have been reported to be 20 to 30% (some investigators∼
have concluded transmission rates may approach 100% )
• normal twins- followed every ~1 to 2 months until 2 years of age∼
with physical examinations and peripheral blood cell counts.
• The risk of developing acute leukemia for nonidentical twins has
been estimated to be a two- to fourfold increase until 6 years of∼
age

7. Acquired Predisposition
• Up to 20% of patients with severe aplastic anemia treated
with immunosuppressive agents
• Environmental Factors: Prenatal exposure to chemical
genotoxic agents, prenatal alcohol consumption, maternal
ingestion of topoisomerase II inhibitors

8. AML subtype
• FAB subtypes M5 (acute monocytic leukemia)
and M7 (acute megakaryoblastic leukemia)
are significantly more common in younger
children

10. Treatment
• Remission-induction regimen, followed by a
course of consolidation therapy, and,
subsequently, an intensification course, which
may include hematopoietic stem cell
transplantation (HSCT).

11. Infantile acuteleukemias

12. Infant Leukemia (< 12 ms of age)
• Leukemia is the second most
common malignancy in
the first year of life
• Annual incidence rate ~ 40
cases per million infant in the
US
• There are ~126 new cases of
Infant ALL and ~67 new cases
of infant AML per year

13. Congenital leukemia (birth to 4 wks of life)
• <1% of all childhood leukemia
• Incidence rate is 1 per 5 million birth
• occur within 4-6 wks of birth
• Only 200 cases been reported in the literatures
• AML is the most common type (64%) than ALL (36%)
• Retrospective identification of leukemia-specific
fusion genes (e.g., MLL-AF4, TEL-AML1) in the
neonatal blood spots and development of
concordant leukemia in identical twins indicate some
leukemias have a prenatal origin.
Greaves MF, Maia AT, Wiemels JL, Ford AM: Leukemia in
twins: Lessons in natural history. Blood 102:2321, 2003

14. Diagnostic criteria

15. INFANTILE LEUKEMIAS

16. EPIDEMIOLOGY
• Overall incidence- 36 cases/ million live births.
• The ratio of ALL to AML in infancy is reported to be between 1
and 1.5 whereas the percentage of ALL cases is about four
times that of AML in older children (less than 15 yrs)
• In infants (1st year of life )
AML- comprise 6-14% of pediatric AMLs
ALL- comprise 2.5-5% of pediatric ALLs.
BLOOD, JULY 2000 VOL 96 (1) 24-33 J Natl Cancer Inst Monogr 2008;39: 83 – 86

17. EPIDEMIOLOGY
• Sex
• White infants experience about a 50 % higher risk
than Black infants
• Highest rates of infant leukemias- Japan, Australia
and Los Angeles.
PNAS April 25, 2000 vol. 97(9)4411–13.
Infants Older children
ALL F>M M>F
AML F>M M=F

18. Clinical Presentation Of Infantile Leukemia
• Variable
• Hyperleukocytosis
• Organomegaly (70-80%)
• Respiratory distress
• Hydrops Fetalis (jaundice, pleural effusion, ascitis)
• 25-30% develop skin lesions (Leukemia Cutis)
– 50% of cases are initial sign
– 10% of cases occur in the setting of normal BM
• CNS involvement,(50%)
• lymphadenopathy (25%)

20. Molecular Basis of Pediatric Leukemias
~80% of cases of infant ALL and ~80% of FAB M4/M5 AML in infants and young children

21. ALL
Presentation and Natural History
• At initial diagnosis, ALL in infants is characterized by
-white blood cell count of >50 x 109
/l
-frequent hepato-splenomegaly,and
-involvement of the CNS (14 to 41% compared with
5% in older children
• ALL with MLL rearrangement is the most common
leukemia in infants <1 yr of age.

22. ALL
Morphology & immunological phenotype
• FAB morphology is L1 more often than L2 .
• The immunophenotype is usually that of immature B-lineage
precursors and is characterized by a lack of CD10 expression
and the coexpression of myeloid-associated antigens.
• These findings suggest that the classic form of infant ALL
originates in a stem cell that has not fully committed to
lymphoid differentiation.
• T-cell ALL accounts for up to 20%of ALL.

24. Cytogenetics

26. IMMUNOPHENOTYPE

27. Infant AML

28. AML with MLL rearrangement
Presentation and Natural History
• Hepatosplenomegaly, and high white blood cell
countat diagnosis.
• High percentage of CNS involvement.
• Leukemia cutis and chloromas and DIC are more
common on infant AML than ALL.

29. AML
Morphology & cytochemistry
• Majority of AML in infants are of FAB M4 or FAB M5
morphology.
• Monoblasts and promonocytes are typically
predominate.
• These cells usually show strong positive NSE and
often lack MPO reactivity.

30. BM P-421/08

31. Immunophenotype
• AML with MLL translocation are associated with
strong expression of CD33, CD65, CD4 and HLA-DR,
while expression of CD13, CD14 and CD34 are often
low.
• Most adult AML cases with 11q23 abnormalities
express markers of monocytic differentiation like
CD14,CD4,CD11b,CD11c, CD64,CD36 and lysozyme.

32. Cytogenetics
• 60% of infant AMLs have an MLL gene abnormality.
• The t(9;11) translocation is the most common translocation in
AML in infants, followed by the t(11;19), t(10;11) and t(6;11).
• The FAB M4 or M5 cases without MLL gene translocation
include
-leukemias with inv(16), which are FAB M4 with
eosinophilia (FABM4eo)
-leukemias with monosomy 7
-random cytogenetic abnormalities,or
-normal karyotypes

33. Infant AML with t(1;22)
• AML with t(1;22) RBM15-MKL1 is an AML generally
showing maturation in the megakaryocyte lineage.
• Representing <1% of all cases.
• Most commonly occurs in infants without down
syndrome, with a female predominance.
WHO 2008

34. Presentation
• Clinically pts present with organomegaly, anemia,
thrombocytopenia and elevated white cell count.
• The PB and BM blasts are similar to those of acute
megakaryoblastic leukemia of AML , NOS
• Cytochemical stains for SBB and MPO are
consistently negative.

35. Immunophenotype
• The megakaryoblasts express CD41,CD61 and less
frequently CD42.
• The myeloid associated markers CD13 and CD33 may
be positive.
• CD34, CD45 and HLA-DR are often negative.

36. Cytogenetics
• In most cases t(1;22) occurs as a sole karyotypic
abnormality.
• Recent studies found that these pts respond well to
intensive AML chemotherapy with long disease free
survival.

37. Mixed phenotype acute leukemia
• This is a rare leukemia that is relatively common in infancy
with MLL rearrangements.
• Many cases of ALL with MLL translocations express myeloid-
associated antigens,but these should not be considered
MPAL.
• Most commonly these leukemias display a dimorphic blast
population, with one population clearly resembling
monoblasts and the other resembling lymphoblasts.
• However, in other cases they appear only as undifferentiated
blast cells.

38. Immunophenotype
• In the majority of cases it is possible to recognize a
lymphoblast population with a CD19+,CD10- pro B-
immunophenotype.
• Along with a separate population of myeloid lineage,
usually monoblastic cells can be demonstrated.
• All cases have rearrangement of the MLL gene with
most common translocation t(4;11).
• This is a poor prognosis leukemia.

39. Molecular pathogenesis
• The most common genetic events occurring in
infants < 12 months, both in ALL and AML, are the
rearrangements of the MLL gene.
• By genetic analysis, it is estimated that nearly 60% of
infant AMLs and 75% – 80% of infant ALLs have an
MLL abnormality in their leukemia cells.
• Has many fusion proteins
• Most common are AF4 on ch 4q21, ENL on ch 19p13
and AF9 on ch 9p22.
Int J Hematol. 2005;82:9-20

40. • MLL (a/k/a ALL-1,HRX) is located on chromosome 11
band q23 and is a frequent target of chromosome
translocations in hematopoietic malignancy.
• MLL gene fusions are particularly prevalent in 2
situations:
Infant leukemia
Treatment-related secondary leukemia (mostly
AML).
• The existence of MLL fusion is usually an indicator of
poor prognosis.

41. • One of the critical functions of MLL appears to be to
maintain expression of Hox genes such as HoxA9 and
HoxC8, which are themselves essential regulators of
development.

43. MLL FISH Green = 5’ MLL Red = 3’ MLL

44. Etiopathogenesis
• There is no doubt that the risks of developing early
acute leukemia are modulated by complex
interactions between inherited predispositions,
environmental exposure to damaging agents and
chance events.
• The molecular epidemiological approach to genetic
studies has suggested the concept that most, if not
all, childhood acute leukemia cases originate in
utero.
Brazilian Journal of Medical and Biological Research (2007) 40: 749-760

46. Risk factors

47. Mechanism of leukemogenesis
• The mechanisms of leukemogenesis in early infancy
are related to the fact that the growing fetus is more
sensitive to the effects of potential DNA damage
insults during the early stage of pregnancy.
• Many studies supports the theory that the exposure
of pregnant women to substances that inhibit
topoisomerase II could be a critical event in the
development of leukaemia in infancy.

49. DNA topoisomerase II inhibitors

50. • One mechanism leading to ALL1/MLL/HRX
translocations might be chromosomal breakage
induced by topoisomerase- II inhibitors within the
ALL1/MLL/HRX gene.
• While another could be represented by mistakes in
DNA-repair mechanisms.
• This hypothesis is supported by Aplan et al showing
that topoisomerase-II–inhibiting drugs cleave double
stranded DNA at a site in ALL1/MLL/HRX exon 9 both
in vivo and in vitro.

51. • DNA topoisomerase II inhibitor therapy-related
leukemias are predominantly seen in AML than ALL.
• If these exposures are so common, why is infant
leukemia so rare?
• The first answer may lie in the timing of exposure
• Secondly, there is growing evidence that
polymorphisms in genes involved in the metabolism
and detoxification of certain chemicals are important
in etiology.
J Natl Cancer Inst Monogr 2008;39: 83 – 86

52. Maternal alcohol intake;
• The mechanism is explained by the ethanol induction
of microsomal enzymes, such as cytochrome P450,
which subsequently activate pre-carcinogens .
• The same study showed that paternal smoking one
month prior to pregnancy was associated with an
increased risk.
J Natl Cancer Inst 1996; 88: 24-31.

53. High-birth weight
• Since insulin-like growth factor-1 is important in
blood formation and regulation and has been shown
to stimulate the growth of both myeloid and
lymphoid cells in culture.
• It was postulated that high levels of insulin-like
growth factor-1 might produce large babies and
contribute to the development of leukemia.
Cancer Causes Control 1996; 7: 553-559.

54. Differential diagnosis
1.Other causes of Leukemoid reactions such as feto-
maternal blood incompatibilities, intrauterine
infections (in which dermal hematopoiesis can
persist), such as syphilis, rubella, cytomegalovirus,
toxoplasmosis, and herpes simplex infections.
2.TMD of down syndrome.

55. Myeloid proliferation in Downs
syndrome

56. Down syndrome
• Frequency of Down in general pediatric
population:
1 per 700 live births
• ALL in 5-30yr age group: 12 fold increase
• ALL in <5yr age group: 40 fold increase
• AML in <5yr age group: 150 fold increase

57. Hematological abnormalities in Down
syndrome

58. TRANSIENT ABNORMAL
MYELOPOIESIS
• Synonyms :Transient myeloproliferative
disorder, Transient leukaemia
• Haematological disorder virtually confined to
Down syndrome
• Presents during fetal life or in the neonatal
period

59. TAM : incidence
• Using the clinical and hematological criteria
10% of all newborns with Down syndrome
have TAM

60. Hematological and clinical features of
TAM in Down syndrome

61. TAM : hematological findings
• Haemoglobin level and neutrophil count are
usually normal in TAM,
• Platelet count is often abnormal—both
thrombocytopenia and thrombocytosis are
reported.
• Blood film may show nRBC, giant platelets and
megakaryocyte fragments

62. TAM

63. CYTOCHEMISTRY OF TAM BLASTS
• positive for acid phosphatases and NSE
• negative for MPO,SBB, CAE and PAS

64. FLOW CYTOMETRY OF TAM BLASTS
• Immature markers : CD34, CD56,CD117
• Early myeloid :CD13, CD33
• HLA-DR : 30%
• Megakaryocyte : CD41, CD61
• may express CD7 (a T-cell antigen)
• Dim CD4 positivity
• CD34 negative in 50% cases and CD41&CD56
negative in 30% cases

65. The importance
of TAM
• TAM can therefore be considered as a
leukaemic or ‘‘pre’’-leukaemic syndrome
• Potential to transform into an acute
leukaemia known as myeloid leukaemia of
Down syndrome (ML-DS)
• Estimated incidence of transformation into
ML-DS: 20–30% of babies with TAM, although
the exact frequency is not known

66. TAM : mutations
• neonates with TAM - mutations in the key
megakaryocyte transcription factor GATA1

67. Diagnostic difficulty
• Phenotypically normal mosaic Down
syndrome
• Only clue to the diagnosis is a blood film
picture typical of TAM
• Therefore any infant with blood film
abnormalities suggestive of TAM should have
cytogenetic analysis to look for trisomy 21.

68. TAM : COURSE OF DISEASE

69. Refer to pediatric hematologist
• Appropriate tests
• Specialised intervention
• Follow-up: for conversion into ML-DS

70. Poor prognostic parameters that may
necessitate treatment with low-dose cytarabine
in DS patients with TMD

71. PROGNOSIS
• Severe liver disease, with fibrosis due to the
production of megakaryocyte-derived growth
factor from blast cells, has a poor prognosis
and may not respond to treatment.
• Despite resolution in most cases of TAM, up to
20% of infants who present to haematology
centres still die of disease

72. Acute myeloid leukaemia in Down
syndrome
• Markedly distinct from the acute myeloid leukaemia that
develops in children without Down syndrome
• Usually presents :1-4 years (median-1.8 years)
• 20–30% of infants with TAM develop ML-DS either by overt
progression or more commonly, after an apparent remission

73. INCIDENCE
• 1-2% of Down have ML-DS within first 5 yrs of
life

74. ANTECEDENT MDS
• An antecedent myelodysplastic phase -70%
• Anaemic and thrombocytopenic with dysplastic changes in
erythroid cells and megakaryocytes
• Marrow often becomes increasingly difficult to aspirate due
to hypercellularity and myelofibrosis

75. ML-DS :BLOOD FILM
• The blood typically shows reduced numbers of normal cells,
with dysplastic changes in all myeloid lineages, and circulating
blasts.
• The bone marrow aspirate and trephine show dysplasia,
increased blasts, abnormal megakaryocytes and variable
myelofibrosis
• Morphology- Usually M7
• Occasionally, other FAB types (M0, M1 and M2)

76. CD 41 +ve blasts
by APAAP
Acute Megakaryoblastic Leukemia: AML-M7

77. Treatment of ML-DS
• The basis of the favourable response is primarily
increased sensitivity of the ML-DS blasts to cytarabine
• Contemporary regimens produce 5-year survival rates
of 80%
• The main reason for treatment failure is toxicity
(resistant disease and relapse are rare), predominantly
due to mucositis and infection.
• Thus, current studies aim to reduce treatment
intensity when compared with children with acute
myeloid leukaemia who do not have Down syndrome

78. DS-AMKL v/s non-DS AMKL
• DS children have a 500-fold increased risk of developing
AMKL
• DS AMKL -narrow temporal window before 4 years of age
• In some, but not all cases of DS-AMKL, there is documented
evidence of previous TMD, and the megakaryoblasts in
AMKL and TMD are morphologically,
immunophenotypically, and ultrastructurally similar
• DS -AMKL has an unusually good prognosis
• TMD and AMKL show a distinct pathogenetic basis

79. GATA1
• GATA1 is a DNA-binding transcription factor encoded on the
X-chromosome (Xp11.23)
• Key regulator of megakaryocyte, erythroid, eosinophil, and
mast cell differentiation
• Acquired somatic mutations in one copy of GATA1 were
demonstrated both in TMD and in DS AMKL.
• These mutations disappeared with resolution or remission of
disease

80. GATA1
• N-terminal truncation of GATA1 could confer a selective
advantage for proliferation of hematopoietic cells
• Altered expression of any number of chromosome 21 genes
• One of these includes RUNX-1, a key hematopoietic gene
often deregulated in leukemogenesis.

81. Why does the TMD clone extinguish
• Though GATA1 mutation provides a
proliferative advantage, it fails to immortalize
the clone
• Results in a self-limiting illness

82. Model of the relationship between
GATA1 mutations and TMD and AMKL in DS

83. LINK BETWEEN TAM AND ML-DS
• TAM and ML-DS blast cells have near identical
morphology, immunophenotype and ultrastructure.
• GATA-1 mutation is distinct for TAM and ML-DS, but
not other Down syndrome and non-Down syndrome
leukaemias

84. TAM and ML-DS: a multi-step model of
leukemogenesis
• First, a fetal haemopoietic cell has to be trisomic for
chromosome 21.
• The second required event is acquisition of a GATA1 mutation
that results in production of a N-terminal truncated GATA1
protein
• As GATA1 is encoded on the X-chromosome, in both males
and females (due to X inactivation) only the mutant N-
terminal GATA1 is expressed
• It is likely that GATA1s is a weak oncogene that fails to control
excessive megakaryocyte differentiation

85. TAM and ML-DS: a multi-step model of
leukemogenesis
• As not all cases of TAM progress to ML-DS,
additional, genetic or epigenetic events are required
for progression to ML-DS
• Presumably, in cases where these mutations are not
acquired the TAM clone extinguishes

86. ALL-DS
• ALL-DS is 1.7 times more frequent than ML-DS
• clinical features of acute lymphoblastic leukaemia are similar
in children with or without Down syndrome
• Most children (>90%) have a precursor B-cell
immunophenotype (CD79a+,CD10+, CD19+)
• In Down syndrome, ALL is more likely to have an adverse
(hypodiploidy) rather than favourable prognostic karyotype
(high hyperdiploidy and t(12:21))

87. Type of leukemia Genetic abnormality Reported number of cases
DS-ALL : Chromosomal:
Intragenic:
- t(12;21)(p13;q22)
- t(8;14)(q11;q32)
- del(9p)
- add(X)
-JAK2 (ΔIREED, R683S,
R683G, R683K)
-PTPN11 (E76K)
-RAS (G12D)
17/322
4/209
15/186
80/238
28/130
1/10
1/10
TMD Intragenic: -GATA1
-JAK3
-TP53
73/75
5/40
1/13
DS-AMKL Chromosomal:
Intragenic:
-Trisomy 8
-Monosomy 7/complete
or partial del(7q)
-GATA1
-JAK3
-FLT3
-TP53
-JAK2
6/34
7/34
58/65
7/53
2/35
6/28
2/32

88. Pediatric MDS

89. Disease Blood findings Bone marrow findings
Refractory cytopenia with unilineage
dysplasia (RCUD)
-Refractory anemia (RA)
-Refractory neutropenia (RN)
-Refractory thrombocytopenia (RT)
- Unicytopenia or
bicytopenia1
- No or rare blasts2
- Unilineage dysplasia: > 10% of the cells in
one myeloid lineage
- < 5% blasts
- < 15% erythroid precursors are ring
sideroblasts
Refractory cytopenia with ring sideroblasts
(RARS)
- Anaemia
- No blasts
- > 15% erythroid precursors are ring
sideroblasts
- Erythroid dysplasia only
- < 5% blasts
Refractory cytopenia with multilineage
dysplasia (RCMD)
- Cytopenia(s)
- No or rare blasts (<1%)2
- No Auer rods
- <1 x 109
/L monocytes
- Dysplasia in >10% of the cells in > two
myeloid lineages
- < 5% blasts
- No Auer rods
- + 15% ring sideroblasts
Refractory anaemia with excess blasts-1
(RAEB-1)
- Cytopenia(s)
- < 5% blasts2
- No Auer rods
- <1 x 109
/L monocytes
- Unilineage or multilineage dysplasia
- 5-9% blasts2
- No Auer rods
Refractory anaemia with excess blasts-2
(RAEB-2)
- Cytopenia(s)
- 5-19% blasts2
- Auer rods + 3
- <1 x 109
/L monocytes
- Unilineage or multilineage dysplasia
- 10-19% blasts2
- Auer rods + 3
Myelodysplastic syndrome with isolated
del(5q)
- Anaemia
- Usually normal or
increased platelet count
- No or rare blasts (<1%)
- Normal to increased megakaryocytes with
hypolobated nuclei
- < 5% blasts
- Isolated del(5q) cytogenetic abnormality
- No Auer rods
Myelodysplastic syndrome- unclassifiable
(MDS-U)
- Cytopenias
- < 1% blasts2
- Unequivocal dysplasia in less than 10%
cells in one or more myeloid cell lines when
accompanied by a cytogenetic abnormality
considered as presumptive evidence for
diagnosis of MDS
- < 5% blastsChildhood myelodysplastic syndrome
Provisional entity: Refractory cytopenia of
childhood (RCC)
- Cytopenias
- < 2% blasts
- Unilineage or multilineage dysplasia
- <5% blasts

90. Pediatric MDS
Classification
• Refracory cytopenia of childhoodRCC (peripheral blood [PB] blasts
2% and BM blasts 5%),
• Refractory anemia with excess blasts (RAEB; PB blasts 2%-19%
and/or BM blasts 5%-19%) and
• RAEB in transformation (RAEB-T; PB and/or BM blasts 20%-29%)
• Secondary MDS:after prior chemotherapy or radiation therapy,
after prior acquired aplastic anemia, or in IBMF disorders and
familial diseases.
Classification of Childhood Aplastic Anemia and Myelodysplastic Syndrome. Charlotte
M. Niemeyer and Irith Baumann. American society of hematology

91. EPIDEMIOLOGY
 12-20% of children with MDS progress to AML
 Account for 1 to 5.5% of all pediatric hematological
malignancies (Indian Pediatrics 2001; 38)
 Near-equal sex distribution; median survival < 12 months
 The median age is 5-8 yrs (avg. 6.8 yrs)
 Most long-term complications are related to
myeloablative therapy with stem cell rescue. Sequelae
include short stature, obesity, gonadal failure,
hypothyroidism, and cataracts.

92. Refractory Cytopenia of Childhood(RCC)
 Persistent cytopenia
 <5% blasts in Marrow
 <2% blasts in periphery
 Cytological dysplasia
Etiology- unknown
50% of all MDS
M=F
Down’s syndrome excluded
75% have hypocellularity
Trephine is indispensable
Difficult D/D:
Hypocellular RCC vs aplastic anemia / inherited BM failure disorders

93. Presentation
 Median age: 6 yrs.
 Asymptomatic-20%
 Malaise, Pallor(Hb < 10g/dL)-50%
 Bleeding(thrombocytopenia <150X 109
/L)
 Fever
 Infections/ severe neutropenia-25%
 Lymphadenopathy
 No/minimal hepatosplenomegaly
 Macrocytosis
 Dysplasia present ≥ 2 / > 10% single lineage

94. Minimal diagnostic criteria for RCC
Erythropoiesis Granulopoiesis Megakaryopoiesis
PB Dysplastic changes in
at least 10%
neutrophils
<2% blasts
BMA Dysplastic/megaloblastoid
changes at least 10%
precursors
Dysplasia at least 10%
precursors
<5% blasts
Unequivocal
Micromegakaryocytes
Other dysplastic changes
in variable no.
Trephin
e
A few clusters of at least
20 erythroid precursors
Stop in maturation with
increased no. of
proerythroblasts
Increased no. of mitoses
No minimal diagnostic
criteria
Unequivocal
Micromegakaryocytes
IHC is obligatory (CD61,
CD41)
Other dysplastic changes
in variable no.

95. Periphery Marrow
Ovalomacrocytes Megaloblastoid erythropoiesis
Elliptocytes Nuclear budding
Acanthocytes Ringed sideroblasts
Stomatocytes Internuclear bridging
Teardrops Karyorrhexis
Nucleated erythrocytes Nuclear fragments
Basophilic stippling Cytoplasmic vacuolization
Howell-Jolly bodies Multinucleation
ErythroidErythroid

96. -
Myeloid
Periphery Marrow
Pseudo-Pelger-Hue't anomaly Defective granulation
Auer rods Maturation arrest at myelocyte stage
Hypogranulation Increase in monocytoid forms
Nuclear sticks
Hypersegmentation
Ring-shaped nuclei
Abnormal localization of immature
precursors

97. Megakaryocytic

99. BM: RCC, showing an aggregate of dysplastic megakaryocytes.

100. RAEB-T, increased numbers of blasts forming a small cluster (centre) : an abnormal
localization of immature precursors or ALIP

101. Cytogenetics
• Monosomy 7 is the most common cytogenetic
abnormality in childhood MDS (30%)
• Trisomy 8 and trisomy 21 are the second most
common numerical abnormalities.

102. Unbalanced +8
-7 or del(7q)
-5 or del(5q)
del(20q)
-Y
i(17q) or t(17p)
-13 or del(13q)
del(11q)
del(12p) or t(12p)
del(9q)
idic(X)(q13)
Balanced t(11;16)(q23;p13.3)
t(3;21)(q26.2;q22.1)
t(1;3)(p36.3;q21.2)
t(2;11)(p21;q23)
inv(3)(q21q26.2)
t(6;9)(p23;q34)
Recurring chromosomal abnormalities seen in MDS

104. D/D of MDS:
Need ≥1 Marrow Finding & CG
• D/D : Is that of anemia, thrombocytopenia, and/or leukopenia.
Elimination of known etiologies of cytopenias, along with a dysplastic
bone marrow, is required to diagnose a myelodysplastic syndrome.
• Other anemias: megaloblastic
CDA
B12, folate/vitamin E deficiencies
sideroblastic anemia
• Leukemia/pre-leukemia:Megakaryocytic leuk.
Myelofibrosis
PNH
• Toxins: Arsenic, chemotherapy
• Virus: HIV
• Other causes of cytopenias -lupus, hepatitis, renal failure or heart failure,
hemolytic anemia, monoclonal gammopathy. Age-appropriate cancers

105. D/D
 Infections: CMV, Herpes, Parvo B19, visceral leishmaniasis
 Vitamin deficiency: B12, folate, E
 Metabolic disorders: mevalonate kinase def.
 Rheumatic diseases
 Mitochondrial deletions: Pearson’s syndrome
 Inherited bone marrow failure disorders: fanconi,
dyskeratosis congenita,
 Acquired aplastic anemia during hematological recovery

106. Etiology
80% primary. 40% which have an abnormal karyotype
20% secondary. Secondary causes include:
1. Neurofibromatosis type 1 (NF1): JMML;200-500-fold increased
risk.
2. Shwachman-Diamond syndrome is c/b pancreatic insufficiency
with neutropenia. MDS:10-25%
3. Fanconi anemia (4-7%): 48% of patients with FA develop leukemia
or MDS by 40 years. It is often a/w monosomy 7 & duplication of
1q. Diagnosing refractory cytopenia in FA difficult.
4. Familial leukemia (2-6%) /familial marrow failure: JMML, in
families with monosomy.
5. Noonan’s syndrome: germline mutation of PTPN 11 (protein
tyrosine phosphatase SHP2) or K-RAS-35%

107. SECONDARY CAUSES, Cont…
6. Kostmann syndrome (0.6%) is congenital agranulocytosis. Survival
significantly improved with (G-CSF).
7. Congenital amegakaryocytic thrombocytopenia
8. Diamond-Blackfan anemia, Bloom syndrome, Dubowitz syndrome,
& Seckel syndrome
9. Alkylating agents (2-5%) is a/w monosomy 7 & chrom 5 del. Poor
response rates. Epipodophyllotoxins is a/w MDS 1 to 3 yrs after
exposure & often involves rearrangements of the MLL gene,
whereas MDS after therapy with alkylators develops later &
involves del chrom 5 or 7.
10. Topoisomerase inhibitor rarely. Patients usually develop AML.
11. MDS develops in 10-15% of patients with acquired aplastic
anemia who are not treated with stem cell transplant
12. Gain of 1q (Leukemia Research Volume 30, Issue 11, 1437-1441)

108. Mutations in the telomerase component TERC, which are observed in
patients with dyskeratosis congenita, are occasionally seen in pediatric
myelodysplasia syndrome without the typical phenotypic features
The biologic mechanisms implicated in the pathophysiology of myelodysplasia
syndrome to date include:
1.genomic instability,
2.epigenetic changes: Methylation silencing of p15
3.abnormal apoptosis machinery,
4.abnormal signal-transduction pathways
5.immune dysregulation (production of inhibitory cytokines/ T-cell
mediated suppression
6.the role of the bone marrow microenvironment & stromal defect.
7.Clonal disorders
8.Genetic polymorphism - GST-theta1 null genotype
Sharon M Castellino, et al, e-medicine, April, 2008

109. Molecular Genetics of MDS
• AML1/RUNX1 gene: point mutations –may be a useful to differentiates
radio-induced MDS/AML from spontaneous MDS/AML( Radiation
Research; 49, 5:2008)
Gene amplification (c-myc) & overexpression of MDR-1 ( accumulation of
P-170 leading to resistance to chemo)
• Chromosome 7 & 20 abnormalities in Shwachman synd: “mutator
phenotype”
• CALCA / CDKN2B are frequently methylated in pediatric MDS. It suggests
that aberrant methylation in pediatric MDS seems to be similar to adult
MDS, thus pediatric patients could be also benefited with treatment
using demethylating agents.
VIDAL Daniel O et al, Leukemia research, 2007

111. FPC Prognostic Scoring System for Pediatric MDS
At diagnosis
Platelet < 40 x 109
– Score 1
Cytogenetic complexity- Score 2
HbF >10%- Score 1
(2/more clonal structural/numerical abnormalities)
Score 0 having a 5-year survival of 61.6% vs score of 2/3 all
died < 4 yrs of dx.
Passmore et a a study of 68 children , BLOOD
The (IPSS) for MDS in adults seems to have limited prognostic impact in
children ...Leukemia (2003) 17, 277–282

112. Thank you