A 59-year-old man was admitted to our hospital because of swelling of the cervical lymph nodes in December, 1985. On admission, his white blood cell count was 18,600/μl, consisting of 20.5% blast cells, 20% monocytoid cells, 18% eosinophils and 15.5% basophils. A bone marrow study revealed hypercellularity with 67.2% blast cells, 1.6% monocytoid cells and 22% eosinophils. Cytochemically, leukemic cells were myeloperoxidase positive. Esterase stainings supported the diagnosis of acute myelomonocytic leukemia. Eosinophils were chloracetate esterase positive. Chromosome analysis revealed 46, XX, -17, +i (17q). Induction chemotherapy with BHAC-DMP and BHAC-AMP regimens resulted in partial remission.
The number of bone marrow leukemic-colony forming units was 477.5/2 x 105 cells, with 21% monocyte colonies, 24% eosinophil colonies and 10% basophil colonies. The remaining colonies contained various combinations of these three lineages. This suggests that the leukemic clone of this patient arose from a hemopoietic stem cell, for these cells have the capability to differentiate into monocytes, eosinophils and basophils.
