Unusual Karyotype in Acute Myelomonocitic Leukemia: A Case Report.

BACKGROUND/AIM: Acute myeloid leukemia is well characterized by chromosomal aberrations that correspond to various subtypes of acute leukemias. The t(8;21)(q22;q22) is a frequent chromosomal abnormality strongly associated with acute myeloblastic leukemia with maturation (AML-M2), but is rarely associated with other subtypes. Translocation involving a third chromosome could produce new genetic rearrangements that lead to leukemogenesis.

PATIENTS AND METHODS

Conventional cytogenetic analysis and fluorescence in situ hybridization (FISH) were performed to identify the karyotype. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect the AML1/ETO transcript.

RESULTS/CONCLUSION: We herein report a novel rearrangement with a three-way translocation involving chromosomes 8, 21 and another unknown chromosome, in an 83-year-old female patient diagnosed as AML-M4, with an ALM1/ETO negative transcript. This is an uncommon case of AML-M4 with three-way translocation in a new variant of t(8;21) acute myeloid leukaemia. The detailed mechanism of different phenotype expression is unclear. Further study is needed to identify the leukemogenetic transformation resulting from t(8;21) translocation.