RESUMEN
BACKGROUND: We present a case of focal lymphoblastic transformation to erythroid leukemia following acute myeloblastic transformation in a patient with chronic myelogenous leukemia (CML) and discuss its mechanism of occurrence and development. CASE SUMMARY: The presence of the Philadelphia (Ph) chromosome was identified through karyotype analysis, while the BCR-ABL fusion gene was detected using quantitative real-time polymerase chain reaction of the peripheral blood sample. Fluorescence in situ hybridization was used to detect the expression of the BCR-ABL gene in the lymphoma. Antigen expression and gene mutations in the primitive cells were detected by flow cytometry. The analysis confirmed the presence of CML along with focal lymphoblastic transformation to erythroid leukemia. Additionally, the patient was found to have secondary erythroid leukemia, along with multiple new gene mutations and abnormalities in complex karyotypes of chromosomes. CONCLUSION: Our findings suggest a possible molecular basis for the focal lymphoblastic transformation secondary to myeloblastic transformation in patients with CML.