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Slide 1
The purpose of Myelocytic Leukemia: Chronic and Acute is to describe the morphologic diagnosis of granulocytic leukemias and their differentiation from leukemoid reactions. The term "granulocytic" is used interchangeably with "myelocytic." Included with the morphologic diagnosis are demonstrations of cytochemical stains.

The French-American-British (FAB) classification of acute leukemias was published in 1976. The purpose of this classification was to describe and delineate more clearly the acute leukemias so that chemotherapy protocols could be tested by different groups of investigators with similar groups of patients. The two major categories are the acute lymphocytic leukemias (ALL) and the acute nonlymphocytic leukemias (ANLL). ALL is described in the program Lymphocytic Leukemia: Acute and Chronic.

So far the treatment of ANLLs by many induction protocols has shown no differences in remission rate, duration, or survival among the different groups of patients. What is good or bad for one group is good or bad for all. Perhaps some day it will become clear whether this classification is useful or if the ANLLs should be lumped together and all treated the same. At present the real importance of learning to recognize the cell types is that it enables us to differentiate acute from chronic leukemia and to differentiate chronic leukemia from leukemoid reaction. Although any cell line may be involved in a leukemoid reaction, in this program we will consider only the myelocytic variety.

With the Romanowsky stains alone, it is difficult to tell one cell line involved in acute leukemia from another. Cytochemistry, however, helps distinguish cell lines. The minimum number of special stains a hematology laboratory should be equipped with is four. These are (1) iron stain (Perls' reaction) for staining the bone marrow in patients with anemia and preleukemia; (2) leukocyte alkaline phosphatase (LAP) stain, which is used for differentiating chronic myelocytic leukemia (CML) from leukemoid reaction; (3) Sudan black B, or a myeloperoxidase stain, for detecting granulocytes (monocytes also stain but with lesser intensity); and (4) a nonspecific esterase stain, either anaphthyl acetate or (alpha-naphthyl butyrate, for detecting monocytes. Both the acetate and the butyrate reactions are sensitive to fluoride. Results of special staining for esterases will be demonstrated in another program in this series, Acute Myelomonocytic Leukemia, Monocytic Leukemia, and Erythroleukemia. The reagents may be obtained in kit form from Sigma Chemical Company in St. Louis. Manual methods are described in detail by Hayhoe and QuagIino, 1980 (see Suggested Readings).

The following four slides are presented for cell identification. They provide a review of cells of the myelocytic series, and the identification of other cells.

Course Section: 08. Myelocytic Leukemia: Chronic and Acute
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