Leukemic blasts can vary in size and appearance depending on the type of leukemia, however, they are usually very similar to one another. This and the decrease of the remaining cells in the peripheral blood lead to the characteristically monotonous picture of the acute leukemias. Except for the leukemic blasts, there are few mature granulocytes present. In other words, no intermediate stages of maturation can be observed as in chronic myelocytic leukemia. The nuclear cytoplasm is typically minimal. The nucleus exhibits a finely distributed chromatin with 1 to several, distinct nucleoli in most cases. The presence of granules is typical for acute myelocytic leukemia, while the presence of Auer rods is diagnostic. In cases where a specific type of leukemia (acute lymphocytic or acute myelocytic) cannot be classified morphologically, special cytochemical stains (e.g. peroxidase and esterase stain) and the determination of lineage-specific antigens by flow cytometric immunophenotyping or immunohistochemistry.