A new chromosome translocation t(7;16)(q31,q22) change during an acute promyelocytic leukemia relapse

The translocation t(15;17), which results in the PML-RARα fusion gene, is a characteristic chromosomal translocation in acute promyelocytic leukemia (APL). But additional chromosome aberrations in APL are increasingly recognized. Here, we report on a 16-year-old APL patient who had an fms-related tyrosine kinase 3-internal tandem duplication (FLT3-ITD) and a 46,XY,t(15;17)(q22;q21)-16+mar karyotype at diagnosis. The patient achieved complete remission after induction therapy with all-trans retinoic acid and chemotherapy. But he soon relapsed presenting distinctive APL features in the bone marrow and leptomeninges and showing a chromosome translocation change involving chromosomes 7 and 16 besides t(15;17)(q22;q21). The new karyotype 46,XY,t(7;16)(q31;q22),t(15;17)(q22;q21) was determined. To the best of our knowledge, this is the first report of a de novo APL with a chromosome translocation t(7;16)(q31,q22) together with a t(15;17)(q22;q21) and FLT3-ITD mutation.