Trisomy 7 and 8 in Ph-negative chronic eosinophilic leukemia.

The results of cytogenetic analyses of bone marrow and peripheral blood cells in a 67-year-old male with chronic eosinophilic leukemia (EL) are described. Although the patient showed leukocytosis with marked eosinophilia, initial chromosome findings in bone marrow revealed a normal male karyotype. Seven months later, more than 80% of bone marrow cells had a hyperdiploid karyotype (48,XY, +7, +8), the remaining cells being normal. Seven weeks later, the identical abnormal karyotype was observed in about 30% of banded metaphases of stimulated peripheral blood cells. No mitoses were found in unstimulated cultures. No Ph chromosome was observed. So far, trisomy 8 has been described for only two cases of EL, whereas trisomy 7 has never been observed.