Trisomy 21 with t（5; 11） Chromosomal Translocation as New Unfavorable Cytogenetic Abnormalities in Pediatric Acute Myeloid Leukemia Type M2： One Case Report of Nine-year Follow-up and Literature Review

We report one case of pediatric acute myeloid leukemia type 2（AML-M2） who presented with karyotypic aberration of trisomy 21 with the t（5;11） chromosomal translocation. The patient achieved complete remission after two cycles of chemotherapy of daunorubicin, cytarabine and etoposide. Then, follow-up cytogenetic analysis from bone marrow cell cultures demonstrated a normal karyotype of 46, XY. After 9 years, the patient relapsed and the karyotypic abnormalities of trisomy 21 with t（5;11） reappeared. It was concluded that trisomy 21 with t（5; 11） is a new unfavorable cytogenetic aberration in AML-M2.