Mixed Phenotype Acute Leukemia with B/T Lineage and BCR-ABL1 Rearrangement: a Case Report and Literature Review.

BACKGROUND

We report a case of B/T mixed phenotype acute leukemia (MPAL) with BCR-ABL1 rearrangement in a 35-year-old male presenting with hemorrhage, infection, and hemodynamic instability.

METHODS

Laboratory findings showed bicytopenia (hemoglobin 79 g/L, platelets 17 x 10⁹/L), leukocytosis (7.7 x 10⁹/L). Peripheral blood and bone marrow smears showed 22% and 66% myeloperoxidase-negative blasts, respectively. Immunophenotyping identified coexisting T-lineage (cytoplasmic CD3+, CD2+, CD5+) and B-lineage (CD19+, CD79a+, cytoplasmic IgM+) populations. Fluorescence in situ hybridization confirmed BCR-ABL1.

RESULTS

The diagnosis for our case was B/T MPAL with BCR-ABL1 rearrangement. The patient achieved com-plete remission with tyrosine kinase inhibitors per GRALL-2014 protocol and is awaiting matched sibling donor transplantation.

CONCLUSIONS

This case demonstrates the diagnostic complexity and aggressive nature of BCR-ABL1-positive B/T MPAL.