Abstract
A 41-year-old male was admitted to our clinic on March 10. 1979, because of fever and anemia. On admission he revealed systemic lymphadenopathy and hepatomegaly but no gingival swelling nor bleeding tendency.
Haematological examination showed anemia and mild thrombocytopenia. WBC count was 3.9×103/μl of which 72% were blasts with fine azurophilic granulation in the cytoplasm. On the sternal aspiration 97.2% of nucleated cells were the blasts similar to those in peripheral blood. Cytochemically these leukemic cells exhibited strongly positive non-specific esterase activity which was completely inhibited by NaF and weakly positive naphthol AS-D chloroacetate esterase but peroxidase was negative. These findings were coincident with acute monoblastic leukemia (McKenna, 1975). Electron microscopy revealed a few abundant perinuclear fibrillar bundle formation, and ribosome lamella complex-like structure in a small number of the blasts. Electron microscopical diaminobenzidine reaction revealed peroxidase positive granules in the cytoplasm. Scanning electron microscopy detected that blasts changed to have monocytoid surface features after incubation 37°C for 20 min on glass plates. Further, the mononuclear cells of the peripheral blood transformed to macrophage-like cells morphologically and cytochemically in vitro culture with RPMI-1640.
From these findings, it was assumed that the leukemic cells of this case dysdifferentiated into monocytic series in the early stage of the differentiation from the common stem cells and that these leukemic cells were possible to differentiate into macrophage in vitro similar to the normal monocytes.
