Vacuoles are colorless bladder-shaped recesses in the cytoplasm. Lymphocytes are not phagocytic cells, so finding vacuoles in them is less regular than in neutrophils and monocytes.

When almost all lymphocytes show vacuoles, there may be a metabolic disorder or Batten disease; however, both are quite rare. Sometimes vacuoles in lymphocytes are indicative of lymphoproliferative disease.