Acute myelomonocytic leukemia: an unusual variant with both granulocytic and monocytic esterases in the leukemic...

By using the combination of alpha-naphthyl butyrate esterase and chloroacetate esterase for cytochemical detection of monocytes and granulocytes, respectively, we examined and identified five adult patients with acute myeloid leukemia whose leukemic cells often (20 to 30%) had the characteristics of both monocytes and granulocytes. All five patients were men, 23 to 82 years of age. Two patients had manifestations of preleukemia. One of these two patients had received treatment for lymphoma for 12 months before acute myelomonocytic leukemia was diagnosed. One patient had gum hypertrophy, and two had leukemia cutis. At the time of initial examination, four patients had blood leukocyte counts higher than 80,000/mm3 and one had leukopenia. Four patients received chemotherapy; three responded temporarily but died within 1 year after the myelomonocytic leukemia had been diagnosed. The patient with leukopenia has remained in complete remission for 2 years. With more frequent use of double esterase stains for classification of acute myeloid leukemias, this variant of acute myelomonocytic leukemia should be detected more often and its clinical behavior should be better understood.