RESUMO
We report on a rare case of a 3-year-old boy with B-cell acute lymphoblastic leukemia (B-ALL), which was characterized simultaneously with two different fusion transcripts: ETV6-RUNX1 and BCR-ABL1 (e1a2). The patient presented with fever, diarrhea, normal white blood cell counts of 5.9×10(9)/L without circulating abnormal cells, anemia, and thrombocytopenia, as well as an enlarged liver without splenomegaly. The bone marrow was markedly hypercellular with a total infiltration of agranular lymphoid blast cells with a B-II (pre-B) lymphoblastic phenotype: cyCD79α(+), CD19(+), sCD22(+), CD10(+), CD20(-), CD34(+), and sIgM(-), with dim aberrant co-expression of the myeloid-associated markers CD13(+) and CD33(+). Conventional cytogenetic analysis was unsuccessful; however, molecular analysis revealed the BCR-ABL1 (p190) and ETV6-RUNX1 transcripts. A diagnosis of BCR-ABL1 (p190)-positive and ETV6-RUNX1-positive B-ALL was made, and treatment was initiated according to the AIEOP-BFM-ALL2000 protocol. A complete remission was achieved after the first induction course of chemotherapy. Twelve months after the diagnosis, the child is alive with levels of residual disease of <0.05% estimated both by 8-color flow cytometry and real-time quantitative reverse transcription polymerase chain reaction.
