Atypical chronic myeloid leukemia with t(9;22)(p24,11.2), a BCR-JAK2 fusion gene.

We report here on a rare case of BCR-ABL1-negative atypical chronic myeloid leukemia with a t(9;22)(p24;q11.2)translocation and a BCR-JAK2 fusion gene, with resistance to the tyrosine kinase inhibitors imatinib and dasatinib.At two years of follow-up, the patient showed no hematologic response and was submitted to an allogeneic bonemarrow transplantation. Fifty-three days after the procedure, he died due to acute graft-versus-host disease. This BCR-JAK2 fusion gene has so far been found in only five patients in the whole world, with three clinical presentations: myeloproliferative neoplasm, acute lymphoblastic leukemia and acute myeloid leukemia.