[Myelodysplastic syndromes].

Myelodysplastic syndromes (MDS)-previously called "preleukemias"-are clonal diseases of the pluripotent hematopoietic stem cell. Their hallmark is peripheral cytopenias. Early forms are characterized by dysplasia of mature cells in the peripheral blood or erythropoiesis, granulopoiesis or megakaryocytes in the bone marrow, and later stages tend to accumulate blasts. About 30% transform into acute myeloid leukemia. MDS are diseases of the elderly and are prognostically divided into lower and higher risk diseases. Median survival times vary accordingly between 6 months and 10 years. Chromosomal abnormalities are identified in 50% of patients, and single or multiple gene mutations occur in 80%. They are the driving force leading to abnormalities in differentiation and to the accumulation of blasts in the bone marrow. Therapeutic options include supportive care, erythropoiesis-stimulating agents, demethylating agents, and allogeneic stem cell transplantation.