[Cytological classification of adult acute leukemia (author's transl)]

134 cases of acute leukemia in adults were classified according a "double blind" cytological diagnosis, a cytochemical study, and lysozyme assay. Each type has distinct characters, allowing a good nosological definition. The histochemical methods, as well as lysozyme assay are usually unnecessary, particularly in well differenciated myeloblastic, promyelocytic or myelo-monocytic acute leukemia. They are, on the contrary, frequently useful in poorly differenciated myeloblastic or monoblastic leukemia. But, they cannot help to solve every problem in cytological diagnosis: there are still 10% of undifferenciated acute leukemia, the lymphoblastic acute leukemia are not clearly defined and 4% of cases of acute leukemia have atypical characters leading to difficulties in cytological classification. The need for new methods and markers is emphasized.