Refractory anemia with ringed sideroblasts with a low IPSS score progressed rapidly with de novo appearance of multiple karyotypic abnormalities and into acute erythroleukemia (AML-M6A).

We report here a case of refractory anemia with ringed sideroblasts (RARS) with a low risk group by the International Prognostic Scoring System (IPSS) at the time of diagnosis but had a rapid disease progression. Although the patient showed a normal male karyotype at the time of RARS diagnosis, his marrow cells had del(5)(q14) and add(17)(p12) abnormalities 2 months after the diagnosis, and later the marrow cells had multiple abnormalities and the patient expired 6 months after the initial diagnosis of RARS. The patient was diagnosed as having RARS with a low risk group by the IPSS classification, however, one should keep in mind that some patients with myelodysplastic syndromes with low risks by either the French-American-British (FAB) classification or the IPSS classification may have progressive disease and subsequential cytogenetic analysis could predict the disease progression.