f. Hypersegmentation. A normal neutrophilic segmented cell has a nucleus
with an average of three lobes or segments. In a hypersegmented cell the nucleus is
broken up into five to ten lobes or segments. This cell usually has a larger diameter
than a normal neutrophilic segmented cell. Hypersegmentation is often seen in
pernicious anemia and folic acid deficiency. They may also be found in chronic
Figure 4-7b. Variations in leukocytes:
g. Atypical Lymphocytes. These lymphocytes are characteristic of infectious
mononucleosis but they may also be seen in apparently healthy individuals and those
with certain other diseases. Atypical lymphocytes are larger than normal and vary in
appearance. Downey and McKinley described three types of atypical lymphocytes, but
this classification has no real clinical purpose.
Size. Large, up to 20 microns in diameter.
(2) Nucleus. The nucleus is oval or kidney shaped with very coarse
chromatin strands not as lumpy as a normal lymphocyte.
(3) Cytoplasm. The cytoplasm is blue to dark blue. Often it is vacuolated
which gives rise to a foamy appearance.
Figure 4-7c. Variations in leukocytes: