[Cytochemical data in chronic monocytic leukemia]

4 cases of chronic monocytic leukemia were observed during several years. In 2 patients there was a final appearance of blastic crisis. During the course of the disease the activity of the naphthylacetate-esterase in the monocytes increased, but the PAS-reaction was lowered. By the help of two cases for comparison - one patient suffering from a chronic myeloid leukemia and intermediate monocytic phase, the other one from a panmyelopathia and monocytic reaction - the morphological resemblance of these phenomena is demonstrated, which cytochemically cannot be separated.