A case of childhood acute myeloid leukemia AML (M5) with a neocentric chromosome neo(1)(qter→q23∼24::q23∼24→q43→neo→q43→qter) and tetrasomy of chromosomes 8 and 21

Hyperdiploidy is rarely observed in childhood acute myeloid leukemia (AML). Described here is the case of a 2½-year-old girl with AML-M5 and 51 chromosomes characterized by double tetrasomy of chromosomes 8 and 21 and also a neocentric derivative chromosome neo(1)(qter→q23∼24::q23∼24→q43→neo→q43→qter). Little is known about the prognostic significance of these chromosomal abnormalities in childhood AML. In the actual case, complete remission was achieved after chemotherapy, which continued for 7 months. No acquired neocentric chromosome 1 has been described previously, even though neocentromere formation has been reported for other chromosomes in neoplasms.