[Transformation of severe aplastic anemia to myelodysplastic syndrome with monosomy 7 in a patient who achieved transfusion independence after immunosuppressive therapy].

A 72-year-old woman was given a diagnosis of severe aplastic anemia, and treated with anabolic steroid and cyclosporin A starting in October 1996. Because this treatment was ineffective, anti-thymocyte globulin (ATG) therapy was started in September 1997. In May 1998, chromosome analysis revealed transformation to myelodysplastic syndrome (MDS), refractory anemia with excess of blasts with monosomy 7 in 60% of metaphase cells. The patient showed gradual hematologic improvement and became transfusion independent. Despite progression to acute myeloid leukemia (FAB-M6) with monosomy 7 in 100% of metaphase cells in December 1998, the hemoglobin level recovered to 13.2 g/dl. In May 1999 the blasts increased rapidly and transformation to acute myelomonocytic leukemia (FAB-M4) was diagnosed. The patient was treated with low-dose Ara-C and aclarubicin with no improvement and died in August 1999. This case demonstrated the transformation of severe aplastic anemia to acute myeloid leukemia via MDS with monosomy 7 associated with transfusion independence after immunosuppressive therapy. These findings suggested a close relationship between aplastic anemia and hypoplastic MDS and the possibility of hematologic improvement based on the growth advantage of abnormal clones.