Myelodysplastic syndromes (MDS) are diseases typical of the adult age, characterized by a clonal alteration of the totipotent staminal cell which causes an inefficient hemopoiesis, reduction of bone marrow cell number, increased bone marrow cell destruction, dysplasia of at least two of the three hemopoietic cell lines and by the tendency to evolve towards acute myeloid leukemia (AML). In patients with MSD, particularly in the advanced primary form, single or multiple chromosomal abnormalities can be found frequently, which may show up and/or modify themselves in any moment of the disease (multistep pathogenetic hypothesis) and whose severity influences significantly the prognosis of MSD patients. In November 1998, a 22 year old female patient (C. C.) was admitted to the Department of Internal medicine of the Garibaldi Hospital, Catania for anemia of unknown origin. The normalities of the hematochemical tests and of other instrumental examinations, induces to perform an osteo-medullary biopsy which revealed the presence of a typical MSD, refractory anemia with excess of blasts type. This disease in its primary form is rare in youth and has a high tendency to evolve in AML. The good clinical conditions of the patient, the absence of chromosomal abnormalities, the normal levels of HbF, the short time interval of the initial diagnosis induced to proceed to bone marrow transplantation, that, as shown by the data reported in the international literature, may give her a good quoad vitam prognosis.