[Acquired idiopathic sideroblastic anemia. Apropos of 39 cases]

We report a series of 39 cases of acquired idiopathic sideroblastic anemia accounting for 12 p. 100 of the 330 cases of myelodysplastic syndrome diagnosed in our department in six years. Patients' mean age was high (70.8 years). Anemia was present in 92 p. 100 of the cases and was of the macrocytic type in 87 p. 100 of the patients. Only two patients (5 p. 100) had neutropenia and two (5 p. 100) had thrombocytopenia. Thrombocytosis was observed in 17 cases (43 p. 100); it was usually moderate. The mean proportion of medullary ring-sideroblasts was 35 +/- 14 p. 100. A clonal abnormality was found in 4 of the 11 karyotype examinations performed. The course of the disease was marked by recurrences of anemia which required regular blood transfusions in 82 p. 100 of the cases. In at least 30 p. 100 of the patients followed up for more than 30 months, these transfusions were responsible for secondary haemochromatosis. Conversely, in only three patients (7.5 p. 100) the disease progressed to acute leukemia. On the other hand, 4 patients (10 p. 100) developed thrombocythemia (greater than 1,000 x 10(9)/1). Median actuarial survival rate was 48 months. There were only two factors of poor prognosis: age over 70 and anemia with less than 8 g/dl haemoglobin at the time of diagnosis. Transfusion haemochromatosis is the principal risk in acquired idiopathic sideroblastic anemia: this risk can be prevented by iron chelating agents in patients with frequent blood perfusions.