1. Week 12: Myelodysplastic Syndrome
Myelodysplasia
Diserythropoiesis
Dismyelopoiesis
Dismegakaryopoiesis
FAB calssification
Ring Sideroblast
Type I and II blasts
WHO classification

2. Myelodysplastic Syndrome
Primary, neoplastic, pluripotential stem cell disorder
Severe cytopenias and maturation abnormality (dysplasia) in one or more cell lines
% of RAEB develop AML, mostly elderly
Evidence of impaired colony formation

3. FAB Classification of MDS (1982)
Refractroy Anemia (RA)
RA with Ringed Sideroblasts (RARS)
RA with Excess Blasts (RAEB)
Chronic Meylomonocytic Leukemia (CMML)
RAEB in Transformation (RAEB-t)

4. WHO Classification of MDS (1997)
RA becomes RA
Refractory cytopenia w/multilineage dysplasia (RCMD) -- complex karyotypes (+8, -7, 7q-, -5, 5q-, 20q-)
RARS becomes
RARS
RCMD w/ ringed sideroblasts
RAEB becomes
RAEB types I and II
5q- Syndrome -- middle age to elderly females; deletion between bands 31 and 33; macrocytosis; good prognosis
MDS, unclassifiable

5. WHO Classification of MDS/MPS
Chronic Myelomonocytic Leukemia (CMML) -- from old FAB MDS
Atypical CML (aCML) -- no Ph chromosome
Juvenile Myelo/Myelomono Leukemia (JMML)
Note: FAB RAEB-t is reclassified as “AML w/multilineage dysplasia following MDS” because definition of AML is 20% blasts with WHO

6. Dyserythropoiesis Anemia Normocytic or macro-ovalocytes
Low retic count
NRBC
Megaloblastic changes
Ringed sideroblast
Pappenheimer bodies
Basophilic stippling

7. Dyserythropoiesis
Ringed sideroblast

8. Dysmyelopoiesis Neutropenia Monocytosis Pseudo Pelger-Huet
Hypogranular PMN
<20% blasts in BM
Type I and type II blasts

9. Dysgranulopoiesis

10. Blasts in MDS Type I blasts No granules Prominent nucleoli
Central nucleus
Type II and III blasts
Few 1o granules
Auer rods
Promyelocyte
Many 1o granules
Less prominent nucleoli
Eccentric nucleus

11. Type I Blast
Type III Blast

12. CMML and NSE

13. Dysmegakaryopoiesis Low platelet count Giant Platelet
Dwarf (micro) megakaryocyte

14. Micromegakaryocyte
Abnormal platelets