[Acute granulocytic leukemia with near-tetraploid chromosome constitution appearing in the late stage of the disease with survival of almost 9 years].

A near-tetraploid clone was observed at the 5th relapse in a 34 year-old female with acute granulocytic leukemia. She was referred to Hiroshima University Hospital presenting with palpitation in May 1978. On admission she had a WBC count of 2,900/microliters with 31.5% blasts, platelet count of 2.4 x 10(4)/microliters and hemoglobin of 2.8 g/dl. A bone marrow aspirate showed hypercellular with 88.5% blasts. Most of them were weakly positive for peroxidase reaction. Occasional Auer rod and/or fine azurophilic granules were observed. DCMP therapy (daunorubicin, cytosine arabinoside, 6-mercaptopurine, and prednisone) was started and the first complete remission was achieved in August 1978. Afterward, the 5th relapse occurred in August 1986 and several kinds of drugs were given without effects. She died 8 years and 9 months after the diagnosis. Karyotype prior to treatment showed a normal diploidy without tetraploid mitoses. However, cells with near-tetraploid (mode: 91) were observed predominantly on the 5th relapse sample and almost all mitoses were occupied with near-tetraploidy at the terminal stage. Results of serial cytogenetic and hematologic study showed a close correlation between the incidence of near-tetraploid mitoses and that of very large blast cells. The significance of tetraploidy in previously reported 44 cases including our case was discussed.