Mixed phenotype acute leukemia, B/myeloid, NOS with near-tetraploidy: a case report.

Acute leukemia in adults is usually associated with a myeloid phenotype, and less commonly presents as an acute lymphocytic leukemia. Rarely, the leukemic blast cells express more than one lineage phenotype and satisfy the diagnostic criteria for an acute leukemia of ambiguous lineage (ALAL), further subclassified as mixed phenotype acute leukemia (MPAL). Near-tetraploidy is an unusual presentation of acute leukemia where the blasts contain 80-104 chromosomes. More commonly associated with acute lymphocytic leukemia, near-tetraploidy has been described in only a limited number of cases of acute myeloid leukemias, and near-tetraploid ALAL is rare. We describe the first report of near-tetraploid MPAL, B/myeloid, not otherwise specified.