This document provides a history and overview of myelodysplastic syndromes (MDS). It describes how MDS was first characterized in the 1930s and named in the 1970s. It outlines the six main types of MDS according to the WHO classification system and related syndromes. It covers clinical features, etiology, prognostic scoring systems, characteristics of the main MDS subtypes, and treatment approaches for MDS.

1. Myelodysplastic
Syndromes

2. History of MDS
 First described in 1938 - 100 patients with
refractory anemia were described; Subsequently,
the terms "preleukemic anemia“ and
“preleukemia” were used.
 In 1963, a variant of acute leukemia was
described, characterized by a prolonged and
often benign clinical course, with a
comparatively lower but variable percentage of
bone marrow blasts; the authors termed this
condition "smoldering acute leukemia"

3. History of MDS
 In the 1970s, chronic myelomonocytic leukemia (CMML)
was recognized as a unique preleukemic syndrome.
 In 1976, the French-American-British (FAB) Cooperative
Group initially defined refractory anemia with excess
blasts (RAEB) and CMML as preleukemic states. Six years
later, the FAB group added three more categories to this
classification scheme and adopted the present term
"myelodysplastic syndromes".
 These disorders, and other members of the MDS "family“
were subsequently defined by the WHO.

5. The Myelodyplastic Syndromes
 Six types of myelodysplastic syndromes
according to WHO.
– Refractory anemia
– Refractory anemia with ringed sideroblasts
– Refractory cytopenia with multilineage dysplasia
– Refractory anemia with excess blasts
– Myelodysplastic syndrome, unclassifiable
– 5q- syndrome (myelodysplastic syndrome associated
with isolated del (5q) chromosome abnormality
 Related syndromes:
– Myelodysplastic/Myeloproliferative diseases

6. Myelodysplastic Syndromes
 MDS Definition:
 A group of disorders presenting with some
evidence of bone marrow failure and
dysplasia of one or more of the myeloid
lineages, with <20% blasts in the blood or
marrow.
 Epidemiology:
 Occur primarily in older patients (most
common > 70 years).

7. MDS – Clinical Symptoms
 Ecchymoses
 Fatigue
 Pallor
 Ecchymoses/petechiae
 Abnormal bleeding
 Infection

8. MDS Etiology
 Two etiologic categories of MDS:
1.) De Novo:
Associated with:
-benzene exposure (gasoline)
-cigarette smoking
-viruses -Fanconi’s anemia
2.) Therapy related:
Associated with:
-alkylating agent chemotherapy
-radiation

9. Prognostic Groups
 Two groups based on survival and evolution to acute
leukemia
 1.) “Good” group
– Refractory anemia (RA)
– Refractory anemia with ringed sideroblasts (RARS)
– 5q - syndrome
 2.) “Bad” group
– Refractory anemia with excess blasts (RAEB)
– Refractory cytopenia with multilineage dysplasia (RCMD)
 MDS unclassified can be either

10. Median Survival – Myelodysplastic
Syndromes
0
20
40
60
80
100
120
RA
EB-2
RA
EB-1
RCMD RC
MD-
RS
RA RARS 5q-
MDS Category
#
Months

11. Prognostic Scoring
 The International Myelodysplastic Syndrome Working
Group developed a scoring system based on 3 variables:
0 0.5 1.0 1.5 2.0
% Blasts
<5 5-10 -- 11-20 20-30
Karyotype Normal, -Y,
del(5q),
del(20q)
Abnormal-
ities
NOS
≥ 3
abnormalities,
chr 7
abnormalities
Cytopenia
0-1 2-3

12. International
Prognostic Scoring
System Data (IPSS)
 Overall median survival was
5.7, 3.5, 1.2, and 0.4 years for
patients with IPSS scores of
zero (low risk), 0.5 to 1.0
(intermediate-1 risk), 1.5 to
2.0 (intermediate-2 risk), and
2.5 to 3.5 (high risk),
respectively.
The time for 25 percent of
the patients in each of the four
risk groups to evolve into
acute leukemia was 9.4, 3.3,
1.1, and 0.2 years,
respectively.

13. IPSS
 Other adverse prognostic factors which may improve the
prognostic value of the IPSS include:
 -CD34 positivity of bone marrow nucleated cells
-Increased expression of the Wilms' tumor gene
(WT1)
-Increased serum beta-2 microglobulin concentration
-Mutations of the FLT3 gene
-Abnormal localization of immature precursors (ALIP).

14. Refractory Anemia
 RA Definition:
 Dyplasia of the erythroid series only.
 Clinically, anemia is refractory to hematinic
therapy
 Myeloblasts < 1% blood and < 5% marrow
 <15% ringed sideroblasts in marrow
 No Auer rods
 Other etiologies of erythroid abnormalities must
be excluded. These include:
– drug/toxin exposure -vitamin deficiency
– viral infection -congenital disease

15. Refractory Anemia
 Epidemiology:
 5-10% of MDS cases.
 Older patients
 Morphology:
 Anisopoikilocytosis on peripheral smears
 Dyserythropoiesis with nuclear
abnormalities (megaloblastoid change)
 < 15% ringed sideroblasts

16. Refractory Anemia
 Genetics:
 25% may have genetic abnormalities
 Prognosis:
 Median survival is 66 months
 6% rate of progression to acute leukemia

17. Peripheral Smear -
Anisopoikilocytosis

18. Dyserythropoeisis on Bone Marrow
Aspirate

19. Megaloblastoid Change on Bone
Marrow Aspirate

20. Refractory Anemia with Ringed
Sideroblasts
 RARS definition:
 Dyplasia of the erythroid series only.
 Clinically, anemia is refractory to hematinic
therapy
 Myeloblasts < 5% in marrow, absent in blood
 >15% ringed sideroblasts in marrow
 No Auer rods
 Other etiologies of ringed sideroblasts must be
excluded. These include:
– Anti- tuberculosis drugs
– Alcoholism

21. Refractory Anemia with Ringed
Sideroblasts
 Epidemiology:
 10-12% of MDS cases.
 Older patients
 Males > females
 Morphology:
 Dimorphic pattern on peripheral smears
– Majority RBC’s normochromic, 2nd population
hypochromic
 Dyserythropoiesis with nuclear abnormalities
(megaloblastoid change)

22. Refractory Anemia with Ringed
Sideroblasts
 Morphology (con’t.)
 < 15% ringed sideroblasts (RS)
– RS = Erythroid precursor with ≥ 10 siderotic
granules encircling 1/3 or more of the
nucleus.
– If excess blasts present, this dictates
diagnosis, despite percentage of RS’s.

23. Refractory Anemia with Ringed
Sideroblasts
 Genetics:
 Clonal chromosomal abnormalities in
 <10%; in fact, development of such an
abnormality should prompt reassessment of
diagnosis.
 Prognosis:
 Median survival 6 years (72 months)
 1-2% rate of progression to acute leukemia

24. Dimorphic Red Cell Population

25. Ringed Sideroblasts

26. Ringed Sideroblasts

27. Megaloblastoid Change

28. Refractory Cytopenia with
Multilineage Dysplasia
 RCMD definition:
 Dyplasia in 10% or more of cells in 2 or
more myeloid lines.
 Myeloblasts < 1% blasts in the blood and
< 5% in marrow.
 No Auer rods
 < 1 x 109
/L monocytes in blood

29. Refractory Cytopenia with
Multilineage Dysplasia
 Epidemiology:
 24% of MDS cases.
 Older patients
Morphology:
 Neutrophil abnormalities may include:
– Hypogranulation
– Pseudo-Pelger-huet (hyposegmentation/barbells)
 Megkaryocyte abnormalities may include
– Hypolobation -Micromegakaryocytes

30. Refractory Cytopenia with
Multilineage Dysplasia
 Morphology (con’t.)
 Erythroid abnormalities may include
nuclear abnormalities such as:
– megaloblastoid change -multilobation
– multinucleation
– In addition:
 Erythroid presursors may be PAS positive
 If >15% of erythroid precursors are ringed
sideroblasts, call = RCMD-RS

31. Refractory Cytopenia with
Multilineage Dysplasia
 Genetics:
 Clonal chromosomal abnormalities found in up to 50% of
RCMD and RCMD-RS cases. The abnormalities include:
– Trisomy 8 -del(7q) -del(5q)
– Monosomy 7 -Monosomy 5 -del(20q)
– Complex karyotypes
 Prognosis:
 Median survival 33 months
 11% rate of progression to acute leukemia
 RCMD and RCMD-RS = similar survival
 Complex karyotypes = worse survival (10-18 months)

32. Pelgeroid (pseudo Pelger-Huet)
Neutrophil

33. Pelgeroid (pseudo Pelger-Huet)
Neutrophil

34. Dyserythropoiesis on Bone Marrow
Aspirate

35. Hypersegmented Neutrophil

36. Micromegakaryocyte

37. Refractory Anemia with Excess
Blasts
 RAEB definition:
 Refractory anemia with 5-19%
myeloblasts in the bone marrow.
– RAEB-1:
 5-9% blasts in bone marrow and <5% blasts in
blood.
– RAEB-2:
 10-19% blasts in the bone marrow
 Auer rods present

38. Refractory Anemia with Excess
Blasts
 Epidemiology: 40% of MDS cases.
 Older patients (over 50 years)
Morphology:
 Dysplasia of all three cell lines often present
 Neutrophil abnormalities may include:
– Hypogranulation -hypersegmentation
– Pseudo-Pelger-huet (hyposegmentation/barbells)
– Pseudo Chediak-Higashi granules
 Megkaryocyte abnormalities may include
– Hypolobation -Micromegakaryocytes

39. Refractory Anemia with Excess
Blasts
 Morphology (con’t.)
 Erythroid precursor abnormalities may include:
– Abnormal lobulation -megaloblastoid change
– Multinucleation
 0-19% myeloblasts in the blood
 5-19% in the marrow
 Bone marrow:
– Usually hypercellular (10-15% hypocellular)
– Abnormal localization of immature precursors (ALIP) may be
present
 Immunophenotype:
– Blasts express CD 13, CD33 or CD117
– The only MDS with a relevant phenotype

40. Refractory Anemia with Excess
Blasts
 Genetics:
 Clonal chromosomal abnormalities found in 30% - 50%
of RAEB cases. The abnormalities include:
– +8 – -5 – del(5q)
– -7 – del(7q) – Complex karyotypes
 Prognosis:
 Median survival, RAEB-1 = 18 months
 Median survival, RAEB-2 = 10 months
 RAEB-1 = 25% rate of progression to acute leukemia
 RAEB-2 = 33% rate of progression to acute leukemia

41. Hypercellular Bone Marrow

42. Blasts and Hypogranulation

43. Myeloblast with Auer Rod

44. Chediak-Higashi-like Granules
 Photograph courtesy of John Scariano, University of New Mexico, Dept. of Pathology

45. Myelodysplastic Syndrome,
Unclassifiable
 MDS-U definition:
 Dysplasia of the neutrophil and/or
megkaryocytic lines and no increased
blasts
 Not otherwise classifiable as RA, RARS,
RCMD and RAEB

46. Myelodysplastic Syndrome,
Unclassifiable
 Epidemiology:
 Incidence unknown
 Older or younger persons
 Associated with a history of exposure to
cytotoxic or radiation therapy
 Morphology:
 BmBx usually hypercellular
 Dyplastic megakaryocytes may be prominent

47. Myelodysplastic Syndrome,
Unclassifiable
 Genetics:
 May be normal, or clonal abnormalities the
same as those found in other MDS syndromes.
 Prognosis:
 Unknown
 Occasionally defining characteristics develop.
Then case should be reclassified.

48. Myelodysplastic Syndrome Associated With
Isolated del(5q) Chromosome Abnormality
( 5q- Syndrome)
 5q- syndrome definition:
 MDS with an isolated del(5q)
 <5% blasts in blood and bone marrow
 Epidemiology:
 Middle age to older women
 Clinical Presentation:
 Refractory anemia, often severe
 Thrombocytosis may be present.

49. Myelodysplastic Syndrome Associated with
Isolated del(5q) Chromosome Abnormality
( 5q- Syndrome)
 Morphology:
– Peripheral Smear:
 Marked macrocytic anemia.
 Slight leukopenia
 Normal to elevated platelets
– BmBx:
 Erythroid dysplasia, varying degrees
 Small, hypolobated megakaryocytes
 Scattered aggregates of small lymphocytes

50. Myelodysplastic Syndrome Associated with
Isolated del(5q) Chromosome Abnormality
( 5q- Syndrome)
 Genetics:
 Deletion between bands q31 and q 33 on
chromosome 5.
 Size of deletion and breakpoints are variable.
 Any additional cytogenetic abnormality excludes
placement in this category.
 Prognosis:
 Good = long survival
 Those who develop more than 5% blasts may
have shorter survival

51. Hypolobated megakaryocytes

52. Myelodysplastic/myeloproliferative
diseases
 WHO category consists of 4 entities
– Chronic myelomonocytic leukemia (CMML)
 Formerly an MDS
– Atypical chronic myeloid leukemia (aCML)
 CML without BCR/ABL fusion gene
– Juvenile myelomonocytic leukemia (JMML)
– MDS/MPD-unclassified

53. CMML Diagnostic Criteria

54. MDS/MPD

55. High vs. low intensity treatment
 High intensity = treatment requiring
hospitalization, and included intensive
combination chemotherapy and hematopoietic
cell transplantation.
Low intensity = outpatient-type treatments,
such as use of hematopoietic growth factors,
differentiation-inducing agents, biologic
response modifiers, and low intensity
chemotherapy.

56. MDS Treatment
 Patients < 60 years of age, who have good or excellent performance
status and who are in the IPSS intermediate-2 or high risk categories
(expected survival 0.3 to 1.8 years) = high intensity therapies.
Patients < 60 years of age, who have good or excellent performance
status and who are in the low or intermediate-1 category (expected survival
5 to 12 years) = low intensity therapy or supportive care.
Patients >60 years of age with good performance status and who are in
the IPSS intermediate-2 or high risk categories (expected survival 0.5 to 1.1
years) = low intensity therapy, although selected patients could be
candidates for high intensity therapies.
Patients >60 years of age with good performance status and who are in
the low or intermediate-1 category (expected survival 3 to 5 years) =
supportive care or low intensity therapy

57. Stem Cell Transplant
 HEMATOPOIETIC CELL
TRANSPLANTATION Allogeneic HCT should be
considered for patients with MDS who are under
the age of 60 and who have an HLA-matched
sibling donor.
 60 and 40% chance of cure after allo-HCT in
low and intermediate risk patients respectively
 Transplant-related mortality and the relapse rate
at five years are as high as 40 percent.

58. Azacitidine
 Azacitadine (Vidaza) the first approved
treatment of MDS
 Azacitidine is a member of a class of drugs in
development known as "hypomethylating" or
"demethylating" agents..
 About 15% of patients in the three trials had
complete or partial responses to Vidaza. (complete or
partial normalization of blood in the bone marrow and normal levels of
blood cells and need for blood transfusions was eliminated)
 Side effects = nausea, anemia, low platelets in
blood, diarrhea, fatigue, irritation at the injection
site, and constipation.

59. Revlimid
 Thalidomide derivative (revlimid) — Revlimid is a
thalidomide derivative without the neurologic toxicity of
the parent compound. Used in MM and promising in
MDS.
 Restoration of a normal karyotype was noted in 11 of 17
informative patients.
 Erythroid response was highest in patients with Low/Int-
1 IPSS scores (71 percent) and in those with the 5q-
syndrome (91 percent).
 Dose-dependent myelosuppression was the most
common adverse event.
 The results of multicenter phase II trials of this agent
are awaited.

60. Decitabine
 Decitabine — Another pyrimidine nucleoside
similar to 5-aza is 5-aza-2'-deoxycytidine (DAC,
decitabine). Both agents strongly inhibit DNA
methylation and are capable of inducing cell
differentiation [86-88].
 25-61% resopnse rate
 Major cytogenetic responses were noted in 31
percent of those with abnormal pretreatment
cytogenetics and were associated with a reduced
risk of death
 High toxicity = fever, infection, sepsis,
neutropenia, anemia, and thrombocytopenia

61. Hypocellular MDS Treatment
 Immunosuppressive drugs — Patients
with hypocellular MDS are believed to
have immune-mediated hematopoietic
suppression, perhaps due to the presence
of an abnormal T cell response
 Some of these patients have responded to
immunosuppressive therapies such as
antithymocyte globulin (ATG)

62. Future Therapies
 Valproic acid (VPA) has been shown to
inhibit histone deacetylase activity and to
synergize with all-trans retinoic acid
(ATRA) in the differentiation induction of
acute myelogenous leukemia (AML) blasts
in vitro.
 Recent studies have found that VPA is of
therapeutic benefit for patients with MDS,
and ATRA may be effective when added
later.