Therapy-related myelodysplastic syndrome with monosomy 5 after successful treatment of acute myeloid leukemia (M2).

We describe a patient who developed myelodysplastic syndrome over 2 years after achieving complete remission of acute myeloid leukemia (AML). The patient was treated in July 1998 with anthracycline, etoposide, and behenoyl cytarabine chemotherapy for AML (French-American-British classification, M2; World Health Organization classification, AML with maturation) and achieved complete remission. At presentation, no chromosomal abnormalities were detected. In December 2000, the patient's peripheral blood revealed pancytopenia, and his bone marrow was hypocellular with trilineage myelodysplasia and no blasts. Chromosomal analysis revealed complex karyotypic abnormalities, including monosomy 5. The patient was diagnosed with high-grade myelodysplastic syndrome (MDS)/refractory anemia with excess blasts (RAEB) subtype. The pancytopenia progressed rapidly, and he died 2 months after the diagnosis of MDS. Therapy-related MDS and AML (t-MDS/t-AML) developing after treatment for acute leukemia is unusual; the primary leukemia associated with most cases of t-MDS/t-AML is acute promyelocytic leukemia (APL). This unusual case suggests that AML excluding APL should be considered a primary hematologic malignancy for t-MDS/t-AML.