Myelodysplastic Syndromes/Neoplasms (MDS)
These are clonal disorders characterized by:
- Cytopenia(s) and dysplasia in one or more of the major myeloid cell lines,
- Ineffective hematopoiesis
- Increased risk of developing AML.
The incidence is 1.8 per million per year in children aged up to 14 years.
Accounts for 4% of hematological malignancies.
Due to an acquired clonal disorder of hematopoietic progenitor cell.
- Growth advantage of clonal cells
- Disturbed differentiation
- Increases apoptosis
Causes ineffective hematopoiesis with dysplasia. Clonal cells can still undergo apoptosis though and so blast cells do not predominate in the marrow.
Can start in one cell line
Usually progresses to pancytopenia and bone marrow failure
Transformation to AML common
Often have cytogenetic abnormalities eg. abnormalities of chromosomes 8, 7, 5, 20, 17 and Y
Sometimes called “preleukemia"
Stem Cells involved by MDS may be:
Pluripotent Stem cell
Multipotent Stem cell restricted to involvement in