A rare case of mixed phenotype acute leukemia: acute myeloid leukemia to early T-cell precursor acute lymphoblastic leukemia transformation

Abstract

Mixed phenotypic acute leukemia (MPAL) comprises of both lymphoid and myeloid markers or blasts in a single population. Diagnostic criteria hinges on classifications provided by identifying these lineages based on cytogenetic markers taken throughout the disease course.  We describe an interesting presentation of a patient who had first presented with Acute Myeloid leukemia (AML) but 8 weeks later transformed into Early precursor T cell ALL (ETP-ALL).  Cytogenetics were taken throughout the course of the cancer and confirmed the presence of a CD34 precursor cell marker. This transformation and cytogenic markers indicated a pluripotent progenitor cell origin confirming the diagnosis of MAPL. This case highlights a pluripotent progenitor origin with initial presentation as AML (myeloid clone) and later as ALL after initial partial response to AML therapy due to clonal evolution.