We reported a 53 years old man with eosinophilic leukemia with trisomy of No. 8 and No. 9 chromosomes. He was admitted to our hospital because of left lower leg pain on 24, Oct. 1984. His peripheral blood count showed a remarkable leukocytosis (99,900/μl) with 58.5% eosinophiles. The bone marrow smear showed a remarkable eosinophilia with the mature and immature cells. The chromosome study showed trisomy of No. 8 and No. 9 chromosomes. He died of the cerebral hemorrage on 28, Oct. 1984. Postmortem examination revealed systemic extensive leukemic infiltration with predominant eosinophilic cells. There was asymmetric septal hypertrophy in the heart and cerebral hemorrage with extensive leukemic infiltration of eosinophiles.
