Therapy-related Trilineage Mixed Phenotype Acute Leukemia Treated with Venetoclax and Azacitidine

This is the first report of therapy-related mixed-phenotype acute leukemia (MPAL) characterized by B-cell, T-cell, and myeloid lineage phenotypes. A 68-year-old man, who was in complete remission after chemoradiotherapy for recurrent esophageal cancer, developed bacterial pneumonia with increasing blasts in the peripheral blood, and a subsequent bone marrow biopsy revealed 85.2% blasts. A flow cytometric analysis revealed cytMPO+, CD19+, cytCD22+, and cytCD3+ markers. The patient was diagnosed with therapy-related MPAL (B/T/myeloid lineage). After the initiation of venetoclax and azacitidine, the patient achieved complete remission, and cord blood transplantation was performed. This case provides novel insights into the therapeutic options for therapy-related trilineage MPAL treatment.