[The bone marrow karyotype in refractory anemia and preleukemia]

The term preleukemia may be used to refer to patients with acquired chronic cytopenias (refractory anemia with an excess of blast cells, refractory sideroblastic idiopathic anemia, or others idiopathic refractory cytopenias) who develop acute myeloid leukemia (AML) months or years later. In these syndromes, an abnormal bone marrow karyotype is found in about 50% cases, like in de novo AML. These abnormalities are similar to those observed in AML (mostly +8, -7, -5 or 5q-). The translocations t(8;21) and t(15;17) are never observed in preleukemia. Correlations exist between hematological data and cytogenetic features namely, in the 5q- syndrome. Thus in preleukemia the cytogenetic analysis is a valuable diagnostic method. At the present time, the prognostic value of the bone marrow karyotype is not clearly established but in single chromosome deletions (5q-, 20q-) the acute transformation is rare or delayed. At the opposite, evolution of the karyotype is generally regarded as a progression to high malignancy.