LAP stains for alkaline phosphatase enzyme activity in the cytoplasm of neutrophils. It is colored dark green/black in the preparation above. The stain is used to help differentiate between a leukemoid reaction and chronic myelocytic (granulocytic) leukemia.
Medium to large lymphocytes contain more cytoplasm than the small lymphcytes and can range in size from 10-14 microns. Their cytoplasm can be blue to gray and contain a few azurophilic granules
acute myelocytic leukemia - M5A
Leukocytes in Alder's anomaly have dark-staining, purplish-red granules that contain precipitated mucopolysaccharides. These granules are sometimes confused with toxic granules, which are not as large and usually stain a darker blue. Alder-Reilly inclusions are seen in Hurler's disease.
A prolymphocyte (#1) is seen in this film with many mature lymphocytes (#2). Prolymphocytes are the stage of lymphocyte development following the lymphoblast stage. The nucleus of the prolymphocyte is younger in appearance than the nuclei of the mature lymphocytes. A large nucleolus is also seen in the prolymphocyte.
acute lymphocytic leukemia
ALL is characterized by lymphoblasts in the bone marrow and peripheral blood. Notice the immature chromatin, nucleoli, and high N:C ratio.
The heterozygous form of congenital Pelger-Huet has mature neutrophils (similar to the one in the picture above) that have a bi-lobed nucleus separated by a thin strand of nuclear material instead of the normal 3-5 lobed nucleus. The shape of the nucleus is often described as "dumbbell" or "pince-nez" (bifocal).
The nucleated "hairy cells" are found in hairy cell leukemia. Notice the streaming cytoplasmic processes.
The neutrophil above contains numerous dark purple, cytoplasmic granules that are often seen in toxic situations such as bacterial infections.