A Male, 11-Years-Old, Admitted In March 2019 With Chronic myelogenous leukemia (CML) in treatment with Imatinib. Three months after diagnosis in outpatient visit was observed increase of splenomegaly and appearing of inguinal and cervical adenomegalies. Bone marrow apiration revealed 70% of blasts, some of them with hemophagocytosis (Figure 1). The immunophenotyping showed blasts positive for CD10, CD19, CD20, CD22, CD79a, CD45, HLA-DR, indicating transformation to B precursors ALL. Bone marrow karyotype was 46,XY,t(9;22), FISH (BCR-ABLES probe) confirmed rearrangement with p210. The patient was treated with higher dose of Imatinib (600 mg/m²), but evolved with bone marrow aplasia and infectious process, being then reajusted to 400 mg/m² with clinical and hematologic improvement. After 30 days had disease aggravation and resistance to Imatinib. The patient initiated EsPh-ALL 2009 protocol, but in D33 with no remission of disease continued with protocol. In September, during consolidation phase evolved with Central Nervous System infiltration and disease persistence, dying for disease in progress. This patient had no clinical findings of Hemophagocytic Lymphohistiocytosis (HLH) and bone marrow cytology showed the several hematopoietic cells inside blast cells.