抄録
We report a case of infantile acute leukemia with t(16;21)(p11;q22). The patient was a phenotypically normal one-year-old girl without lymphadenopathy or hepatosplenomegaly. Her peripheral blood at diagnosis showed anemia, thrombocytopenia, and many circulating blasts. Bone marrow blasts were monocytoid with fine reticular nuclear chromatin, abundant grayish-blue cytoplasm with occasional pseudopods or cytoplasmic projections and active hemophagocytosis. Serum levels of lysozyme and ferritin were normal. These blasts were not stained with butyrate esterase and immunologic study showed KOR-P77+ (anti-megakaryocyte monoclonal antibody), MY9+, Ia-. Electron microscopic examination failed to show platelet peroxidase activity. Remission was not induced by mini-COAP or VP-16 and the patient died of measles pneumonitis. The patient's blasts took typical appearance of megakaryoblasts later in the course, although some of them retained the ability of hemophagocytosis observed in the original blasts.
This case is considered to be quite atypical since leukemic cells with active hemophagocytosis, megakaryoblastic appearance and t(16;21)(p11;q22) have not been reported in the literature.
