Vacuoles are areas of the cytoplasm which do not stain with Wright's stain and appear as holes in the cytoplasm. Their composition may vary; some will contain remnants of bacterial digestion, autodigestion in an aging cell, while others may contain fat. It is not possible to differentiate the various types of vacuoles on Wright stained smears using light microscopy.
Vacuoles may be seen occasionally in an aging granulocyte (degenerative vacuolation), but are seen more frequently and are significant in cases of bacterial infection and septicemia.
