Successful acute lymphoblastic leukemia-type therapy in two children with mixed-phenotype acute leukemia

Area of Science:

• Hematology
• Pediatric Oncology
• Leukemia Research

Background:

• Mixed-phenotype acute leukemia (MPAL) is a rare hematologic malignancy characterized by the co-expression of myeloid and lymphoid markers.
• Optimal therapeutic strategies for pediatric MPAL remain undefined due to limited case information.
• Accurate classification of MPAL can be challenging, with discrepancies between diagnostic criteria like the World Health Organization (WHO) and European Group for the Immunological Characterization of Leukemias (EGIL).

Observation:

• Two pediatric MPAL cases were analyzed, presenting diagnostic complexities.
• Patient 1 was diagnosed with overt MPAL (myeloid and B-lymphoid markers) per WHO and EGIL criteria.
• Patient 2 received a T-cell acute lymphoblastic leukemia (T-ALL) diagnosis by EGIL criteria but was classified as overt MPAL (T-lymphoid, MPO, CD3 positive) by WHO criteria.

Findings:

• Both pediatric MPAL patients received acute lymphoblastic leukemia (ALL)-type chemotherapy incorporating both lymphoid- and myeloid-directed agents.
• Both patients achieved and maintained complete remission following the implemented treatment regimen.
• The study highlights the potential efficacy of combined-modality therapy in pediatric MPAL.

Implications:

• Further research and data collection on pediatric MPAL are crucial for establishing standardized treatment protocols.
• Defining optimal therapeutic strategies, potentially including stem cell transplantation, is essential for improving outcomes in this rare pediatric leukemia.
• This case series contributes to the understanding of MPAL diagnosis and treatment in children.