Rapid improvement of secondary myelodysplastic syndrome from essential thrombocytosis (ET) treated by Azacitidine(AZA)

Abstract

Abstract Background It is well known that secondary MDS is refractory to treatment. In general, high-risk MDS is treated with AZA, but its effect is often delayed. I experienced a case which has rapidly improved to the ET from secondary MDS after 2 courses of AZA. Case report A 70 - year - old woman, who had diagnosed with ET 20 years before and treated with hydroxyurea for 5 years, was admitted to our hospital with pancytopenia. On abdominal CT, it showed splenomegaly. In chromosome testing showed complex karyotypes. Plasma WT-1 level showed a significant high as 96000 copy. In bone marrow aspiration, blasts together indicate to the atypical three strains accounted for 18%, was diagnosed with secondary MDS (RAEB-t, IPSS-R: 9.5 points). Bone marrow biopsy was similar findings and myelofibrosis was not observed. She was treated with AZA at a dose of 75 mg / m2 over a 7-day subcutaneous injection, and was followed for 3 weeks. She withdrawal from transfusion-dependent in the initial treatment, and at the time of 2 the end of the course, her WBC number (990 / µl to 7240 / µl) and Hb level (6.3 g / dl to 13.8 g / dl) were normalized, and her blood platelet count was markedly increased from 56,000 / µl to 1,340,000 / µl. Plasma WT - 1 level decreased markedly from 96000 copies to 430 copies, and the splenomegaly also improved on US study. Bone marrow aspiration showed hyperplastic bone marrow accompanied by a marked increase in megakaryocytes, the three line heterozygosity disappeared, and the blasts decreased to 1.2%. Even in bone marrow biopsy consistent with ET. Discussion Secondary MDS developed with chemotherapy is generally often refractory to treatment. In our case, we withdrew from transfusion dependence with first-time AZA therapy and improved to ET, the original disease at the end of 2 courses. Secondary MDS patients who respond with small number of AZA therapy are extremely rare and are valuable cases.