Benign Proliferative Reactions, Intraepithelial Neoplasia, and Invasive cancer of the Uterine cervix
Fig. 8.3 Parabasal cells.
Round-to-oval cells with relatively large nuclei
and scant dense, cyanophilic cytoplasm. Admixture of leukocytes is due to
inflammation (Papanicolaou x HP).
an increase in the cytoplasmic volume and signs of specific func-
tional qualities of the cytoplasm, such as storage of glycogen
or secretory products. Cells are bound to each other by intra-
cellular bridges called desmosomes. Cytoplasm of intermediate
squamous cells is cyanophilic in staining. Nuclei become only
slightly reduced in size during the passage of the cells through
the intermediate cell layers. The round-to-oval nuclei have a
diameter of about 8 to 10 pm, have a clearly defined nuclear
membrane (Fig. 8.4; see also Fig. 8.18), and contain an evenly
distributed, finely granular chromatin.
The most superficial layers are composed of fairly large
polygonal cells loosely attached to each other. These cells do
not proliferate and represent an end stage in the maturation
process of nonkeratinizing stratified squamous epithelium.
Intercellular attachments—desmosomes—become loose, and
cells constantly exfoliate from the surface. Cells are polygonal
and have a clear, translucent, usually pink-staining, occasionally
cyanophilic cytoplasm; sharply defined boundaries; and a small,
often pyknotic central nucleus. Superficial cells have a diameter
of approximately 40 pm. The nuclear diameter is 3 to 5 pm. The
eosinophilic staining of the cytoplasm is caused by the presence
of prekeratin proteins. Fibrillary strands of keratin can some-
times be recognized in the cytoplasm of the most superficial
eosinophilic staining cells. Rarely, superficial cells may contain
keratohyalin granules in the cytoplasm. These granules are sup-
posedly derived from the granular cell layer of an altered—kerat-
inized—stratified squamous epithelium.
The entire maturation cycle of a normal squamous cell takes
approximately 4 days. The maturation process can be accelerated
significantly under estrogenic stimulation. Although the influ-
ence of estrogenic hormones is predominantly evident on the
vaginal epithelium, the ectocervical squamous and endocervical
columnar epithelium, contrary to what is often stated, also show
a cellular reaction to ovarian hormones. During the reproductive
years, reduced maturation of the cervical squamous epithelium
may be found as a result of the action of oral hormonal contra-
ceptives. Before reproductive age, the start of which is marked
by the first menstrual period, or menarche, the epithelial lining
of the vagina and ectocervix is relatively thin and composed
of less mature cells of a parabasal type (Fig. 8.5). Cells do not
Fig. 8.4 Normal superficial and intermediate squamous cells
desquamated from normal nonkeratinizing squamous epithelium
(Papanicolaou x OI).
Fig. 8.5 Atrophy of ectocervical squamous epithelium.
is reduced in thickness and composed almost entirely of immature parabasal-
type cells (H&E x HP).