CHAPTER 19
Female Reproductive System
383
Figure 19-12A.
Cervix.
H&E,
3
17; inset
3
350
The inferior part of the uterus forms the
cervical canal
, which bulges
into the vagina. The
internal os
is the opening from the endocervical
canal to the uterus; the
external os
is the opening to the vaginal canal.
The surface of the
endocervix
is lined by simple columnar epithelium,
which consists of mucus-secreting cells (
inset
); the
ectocervix
is lined
by stratiF ed squamous epithelium. The cervix contains long branched
mucous glands known as
cervical glands
; when these glands become
obstructed they form cervical cysts (
nabothian cysts
). The secretion
of the cervix changes depending on the stage of the menstrual cycle;
however, the mucosa of the cervix does not slough off as does the
endometrium of the uterus. The
cervical stroma
is composed of dense
connective tissue mixed with a small amount (about 15%) of smooth
muscle. Usually, the cervix has a narrow canal; however, during deliv-
ery, dilation of the cervix allows the baby to pass through the canal.
Branched
cervical
glands
Cervical
cysts
Internal os
Endocervical
canal
Ectocervix
Stratified
squamous
epithelium
(ectocervix)
External os
Cervix
Cervical stroma
Cervical stroma
Cervical stroma
Simple columnar
Simple columnar
epithelium
epithelium
(endocervix)
(endocervix)
Simple columnar
epithelium
(endocervix)
Endocervix
Endocervix
Endocervix
A
The
cervical
transformation
(
transition)
zone
is the area of the
cervical mucosa between the original
squamocolumnar
junction
and the restored or new squamocolumnar junction that is formed
through the processes of squamous metaplasia and squamous
epithelialization. The majority of
cervical
carcinomas
arise in this
zone, and it is important that this area be sampled during screening
with a
Papanicolaou smear
.
CLINICAL CORRELATION
Figure 19-12B.
Cervical Cancer.
H&E (
upper left
),
3
20; (
lower right
),
3
115
Cervical cancer
is a malignant neoplasm of the uterine cervix, the major-
ity of which are
squamous cell carcinomas
. Risk factors include the early
onset of sexual activity, multiple sexual partners, and exposure to
human
papillomavirus (HPV). Invasive squamous cell carcinoma
is preceded by
precursor lesions called
cervical intraepithelial neoplasia
, in which dysplas-
tic epithelial changes are present. The majority of intraepithelial lesions
are related to infection by HPV. The introduction of screening using the
Papanicolaou smear
, or
“Pap” smear
, has dramatically reduced the inci-
dence of invasive cervical lesions. Symptoms of cervical cancer include
abnormal vaginal bleeding, postcoital bleeding, and vaginal discharge. His-
tologically, the cancer typically arises in the
cervical transformation zone
and may show superF
cial ulceration with
endophytic
or
exophytic
growth
patterns. The cancer can spread by direct invasion to nearby tissues and
organs or metastasize through hematogenous or lymphatic routes. Garda-
sil, a vaccine against certain HPV types, is used in young women to prevent
infection by the virus. Treatment options include surgical removal of the
uterus (hysterectomy), radiation therapy, and chemotherapy.
Squamous
epithelium
Squamous cell
carcinoma
B
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