Medical Importance
The myelodysplastic syndromes are clonal hematopoietic disorders
that commonly cause macrocytic anemia in older patients. While the
progeny of the mutant stem cells dominate the bone marrow, blood cell
production rates are usually low because bone marrow cells do not
mature normally and many of them undergo apoptosis in the bone marrow
before reaching the peripheral blood. Thus myelodysplasia is
characterized by ineffective hematopoiesis. The characteristic feature
in the bone marrow is dysplastic and/or megaloblastic maturation.
Although the differentiation process is less perturbed than in acute
leukemia (where the leukemic cells are incapable of maturing beyond the
blast stage), subtle differentiation abnormalities define
myelodysplasia. Over time, the bone marrow cells of a substantial
number of patients with myelodysplasia evolve to acute
leukemia. Patients with myelodysplasia cannot be cured except by stem
cell transplantation, and represent a considerable therapeutic
challenge due to the limited effectiveness of most medical therapies.
Objectives
- Describe the typical age and classic peripheral blood findings of patients with myelodysplasia.
- Describe the bone marrow findings and cytogenetics seen in patients with myelodysplasia.
- Describe three laboratory determinants of prognosis in patients with myelodysplasia.
- Name
three treatments used in patients with myelodysplasia, the goals of
such therapy, and the results of each treatment in terms of response
rate, cure, and/or impact on survival.
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