Xulin LU, Jigang XIAO, Xiaojin CAI, Chengwen LI, Zhijian XIAO
Turkish Journal of Hematology - 2026;43(2):165-166
A 14-year-old male patient presented with dizziness, nausea, and fever. Blood tests revealed white blood cell count of 89.71x109/L, hemoglobin of 98 g/L, and platelet count of 392x109/L. Bone marrow aspirate and peripheral blood smear revealed 57% and 34% blasts, respectively. Flow cytometry (FCM) revealed two abnormal cell populations, one of which expressed CD34, CD123, TDT, CD38, HLA-DR, CD33, CD13, CD117 (strong), CD7, and CD36 (partial) while the other expressed CD19, cCD79a, CD22, TDT, CD34, CD38, HLA-DR, CD13, CD33, CD123, and CD117 (partial). Cytogenetic analysis revealed 46,XY,t(9;22)(q34.1;q11.2),inv(16)(p13.1q22)[20]. Fluorescence in situ hybridization (FISH) revealed BCR::ABL1 and CBFB rearrangement positivity. Whole-transcriptome RNA sequencing of fusion genes revealed the existence of CBFbeta::MYH11, BCR::ABL1 (p210), and ABL1::BCR. After one cycle of chemotherapy including vincristine, daunorubicin, PEG-asparaginase, and prednisone concurrently with dasatinib, morphological complete response was achieved and minimal residual disease was negative by FCM, but both fusion signals remained positive by FISH. Considering the presence of splenomegaly and the BCR::ABL1 fusion signal detected in lobulated granulocytes, this case was deemed to have originated from the blast crisis phase of chronic myeloid leukemia. Cases of acute leukemia of mixed B/myeloid lineage together with BCR::ABL1 and CBFbeta::MYH11 have rarely been reported to date. Early use of tyrosine kinase inhibitors in conjunction with hematopoietic stem cell transplantation may improve outcomes.
