Mixed phenotypic acute leukemia.

Mixed phenotypic acute leukemias (MPALs) are a heterogeneous group of rare leukemias constituting about 1% to 5% of all leukemias. MPAL is defined as an acute leukemia that demonstrates expression of a combination of antigens of different lineages so that it is not possible to assign a single lineage to that leukemia. These leukemias have been characterized by relative therapeutic resistance. We present a case of a woman with an acute MPAL diagnosed as a B/myeloid leukemia.