Inversion of chromosome 16 observed in acute myeloblastic leukemia (M2) with biphenotypic surface markers lacking monocytosis and eosinophilia

Inversion of chromosome 16 was found in a 73-year-old female with acute myeloblastic leukemia (FAB:M2). Complete remission was achieved by combined chemotherapy (DNR, Ara-C, 6-MP, Prednisolone), but she relapsed 6 months later without CNS involvement and died of respiratory failure presumably due to cerebrovascular accident during remission reinduction chemotherapy. Biphenotypic surface markers (CD2+ and CD13+) were observed on relapse. Eosinophilia was not observed throughout. Our patient and the other reported case suggest that biphenotypism and the lack of eosinophilia and monocytosis in inv (16) leukemia may be correlated with a poor prognosis.