Spatially segregated B- and T-lymphoblasts in mixed-phenotype acute leukemia with BCR::ABL1.

BACKGROUND

Mixed phenotype acute leukemias (MPALs) account for approximately 2-5% of acute leukemias.

PURPOSE: We report a case of MPAL with BCR::ABL1 demonstrating striking spatial segregation of B- and T-lymphoblasts involving the bone marrow and cervical lymph node, respectively.

METHODS

Morphologic, immunophenotypic, and genetic characterization were performed.

RESULTS

These studies identified two distinct lineage-specific blast populations. Molecular studies demonstrated shared genetic features, supporting a common clonal origin.

CONCLUSIONS

This case expands the clinicopathologic spectrum of MPALs and raises the possibility of lineage-restricted differentiation occurring in distinct tissue microenvironments.