Two independent clones in myelodysplastic syndrome following treatment of acute myeloid leukemia

We describe a 55-year-old Japanese woman with therapy-related myelodysplastic syndrome (t-MDS) with 2 independent Clones, t(1;2)(p36;p21) and t(11;2)(p15;q13). She was diagnosed with acute myeloid leukemia (AML) with cytological features of the bone marrow and peripheral blood. Cytogenctic evaluation revealed a 46,XX karyotype. She received chemotherapy and achieved complete remission (CR). Despite maintenance chemotherapy, site suffered a relapse. Chromosomal analysis showed t(1;2)(p36;p21) in 2 of 20 metaphases. At second CR. this clone transiently disappeared. Nine months later, t(1;2) (p36;p21) was detected again in 3 of 20 metaphases while the patient remained in CR. Six months later, bone marrow examination disclosed trilineage dysplasia without an excess of blasts, suggesting MDS. 1(1;2)(p36;p21) was observed in 16 of 20 metaphases. The clinical course and serial cytogenetic findings were diagnostic of t-MDS.The duration of t-MDS was 6 years. During this period, persistent t(1;2)(p36;p21) and transient t(11;12)(p15;q13) were found. When t-MDS evolved to AML, cytogenetic evaluation revealed 46,XX,t(1;2)(p36;p21),del(7)(q22),add(19)(p13). Int J Hematol. 2002;75: 182-186. (C)2002 The Japanese Society of Hematology.