Abstract
A case of acute megakaryoblastic leukemia was reported. The patient, a 2-year-old boy, was admitted to our hospital because of petechiae and mild anemia. The WBC count in peripheral blood increased to 29, 300/μl with 48% blasts. Bone marrow revealed 74.2% blasts. In cytochemical studies, a large number of blasts were peroxydase negative, naphthol AS-D chloroacetate esterase negative, α-naphthyl butyrate esterase weakly positive, and acid phosphatase positive. The monoclonal antiplatelet glycoprotein II b/III a complex and factor VIII were present on a number of the cells. In ultrastructural cytochemical studies, PPO positivity in the nuclear envelope and endoplastic reticulum were seen in more than 70% of fresh blast cells, while we could not detect it in cultured cells after 5 days incubation. A definite diagnosis of acute megakaryoblastic leukemia was made on the basis cytochemical and EM investigations. For establishment of the disease entity, further studies on many cases by cytochemical, immunological, and ultrastructural examinations are necessary. Chromosomal analysis revealed a karyotype of 48, XY, +19, +20. The patient was treated with a combination of vincristine, Adriamycin, prednisolone, and cytosine arabinoside, and a remission was obtained.
