Diseases of the
Back to Library
The cervix is an important site of pathology,
particularly in women of reproductive age. The ectocervix is covered by squamous
epithelium, and the endocervical canal by mucus-secreting columnar epithelium,
which shows glandular downgrowths. At various stages in a woman's reproductive
life, the junction between the squamous and columnar epithelium migrates onto
the convexity of the ectocervix, then back into the endocervical canal. This
squamocolumnar junction is the seat of most of the epithelial diseases that
occur in the cervix.
The original squamocolumnar junction is usually located in the region of the
external os, but its precise location at birth is influenced by exposure to
maternal hormones in utero.
Around puberty, hormonal influences cause extension of the columnar epithelium
onto the ectocervix, forming an ectropion or cervical erosion. This process is
augmented by a first pregnancy, particularly when it occurs shortly after
Before puberty, the pH of the vagina and cervix is alkaline, but afterwards
bacterial breakdown of glycogen in the vaginal and cervical squamous epithelium
renders it an acidic environment, the pH being about 3.
Exposure of the sensitive columnar epithelium of the ectropion to the
post-pubertal acidic environment of the vagina induces squamous metaplasia and a
transformation zone between the endocervical columnar epithelium and the
ectocervical squamous epithelium. This zone is composed of new squamous
epithelium in an area previously occupied by columnar epithelium.
Thus the squamocolumnar junction is of variable size, but its site always
approximates to the external os. In older women it may retreat into the
The mobility of the squamocolumnar junction, the development of ectropion, and
the formation of the transformation zone are:
(a) The squamocolumnar junction is originally situated in the region of the
(b) At puberty the endocervical epithelium extends distally into the acid
environment of the vagina, forming an ectropion.
(c) A transformation zone forms as squamous epithelium re-grows over the
ectropion. The openings of the crypts may be obliterated in the process, which
leads to the formation of mucus-filled Nabothian follicles.
Chronic cervicitis is produced by the same organisms responsible for infective
vaginitis. The term 'chronic cervicitis' is sometimes applied inaccurately by
clinicians when the area of ectocervix around the external os is red and
irregular; in most cases this is not inflammation, but represents the extension
of columnar epithelium onto the external os, sometimes called ectropion or,
inaccurately, a 'cervical erosion'.
Genuine chronic endocervicitis, with a heavy lymphocytic and plasma cell
infiltrate, may be found in association with infections of the vagina by
Trichomonas, Candida, Gardnerella and the gonococcus.
Cervical polyps are a common cause of intermenstrual bleeding.
Cervical polyps are common abnormalities which, through erosion and ulceration,
may cause intermenstrual bleeding. They are seen in about 5% of women.
Macroscopically they appear smooth, rounded or pear-shaped, and are typically
1-2 cm in diameter. The polyps derive from the endocervix, protruding from the
cervix through the external os. They are composed of endocervical stroma and
glands, the latter often being distended with mucus. The surface of the polyp
may show ulceration and inflammation and, if long-standing, there may be surface
Benign tumours of the cervix are uncommon, the most frequent being leiomyomas
True benign neoplasms of the cervix are uncommon, most nodules associated with
the cervix being endocervical polyps. Leiomyomas may occur in the cervix, but
are less common at this site than in the uterus.
HPV infection is common in the ectocervical epithelium and is an important
aetiological agent in cervical cancer
HPV infection of the cervix is sexually acquired. Over 70 sub-types of HPV have
been defined, each of which has been allocated a number.
Occasionally, HPV infection may produce papillary lesions of cervical squamous
epithelium (condyloma acuminatum), which are similar to those seen on the vulva
. They are usually located on the ectocervical squamous epithelium or on the
squamous epithelium of the transformation zone, and may be multiple.
More often, HPV infection causes flat condylomas.} These cannot normally be seen
with the naked eye, but may be recognizable on colposcopic examination after
painting the cervix with dilute acetic acid, which turns them white.
Histologically the epithelium in flat condylomas is abnormal, with binucleate
cells (particularly in the upper layers of the epithelium), and so-called 'koilocytic
change' in the most abnormal epithelial cells. These viral changes can be
recognized on cervical-smear cytology. Both patterns of wart-virus involvement
of the cervical squamous epithelium are most frequent in the transformation zone
epithelium, and may co-exist with changes of intraepithelial neoplasia.
Cervical intraepithelial neoplasia is an important precursor of invasive
The metaplastic epithelium of the transformation zone is susceptible to change
during reproductive life. Mild degrees of nuclear enlargement can be seen in
response to chronic inflammation, in reparative epithelium, and in association
with HPV infection. However, more severe atypia is now regarded as a pre-neoplastic
proliferation and is called cervical intraepithelial neoplasia (CIN). This
change takes place in the metaplastic epithelium of the transformation zone of
the cervix and is usually associated with infection by HPV.
Three grades of severity are recognized, dependent upon what proportion of the
thickness of the cervical epithelium is replaced by atypical cells.
CIN I corresponds to mild dysplasia. Atypical cells are confined to the lower
third of the epithelium, the upper two-thirds showing normal differentiation and
maturation with flattening of cells.
CIN II corresponds to moderate dysplasia. Atypical cells occupy the lower half
of the epithelium, but evidence of differentiation and maturation with
flattening of cells is seen in the upper half. Nuclear abnormalities may extend
through the full thickness of the epithelium, but are most marked in the lower
half, where there may be increased mitoses with some abnormal forms.
CIN III corresponds to severe dysplasia and carcinoma in situ. Atypical cells
extend throughout the full thickness of the epithelium, with minimal
differentiation and maturation on the surface. Mitotic figures and abnormal
mitoses are present through all layers, and there may be extension of the change
along endocervical crypt necks, and foci of true microinvasion.
These abnormal epithelial changes occur in the transformation zone, but may
extend over the ectocervical surface and up the endocervical canal. In about 10%
of cases, atypia termed cervical glandular intraepithelial neoplasia (CGIN) is
also seen in endocervical epithelium.
Diagnostic cervical cytology
The development of abnormalities in the cervical epithelium is an important
factor in the prevention of subsequent invasive carcinoma of the cervix.
Detection of abnormal cells is based on the presence of abnormal cytology. Using
a specially shaped spatula, cells are scraped from the ectocervix and lower
cervical canal and smeared onto a slide. They are fixed in a preservative
solution and sent to a pathology laboratory for cytological examination after
the addition of Papanicolaou stain (the origin of the term 'Pap smear'). In CIN,
the exfoliated cells have an increased nuclear:cytoplasmic ratio and a clumped,
irregular chromatin pattern, being termed dyskaryotic.
If atypical epithelial cells are detected in a cervical smear, patients are
recalled. The site of abnormal epithelium is identified by colposcopy, and the
diagnosis confirmed by biopsy of the abnormal area. If the lesion is
non-invasive and completely visible, not extending high up into the endocervical
canal, ablation of the atypical area can be performed using laser or cryotherapy.
If the topmost edge of the lesion cannot be seen in the endocervical canal, the
lesion has to be removed as part of an excision biopsy.
Invasive carcinoma of the cervix is most commonly squamous-cell carcinoma
Invasive carcinoma of the cervix may occur at any time during the reproductive
and post-menopausal years, but the average age of development is about 50 years.
It accounts for 3-5% of cases of carcinoma in females.
Macroscopically, early lesions appear as areas of granular irregularity of the
cervical epithelium, progressive invasion of the stroma causing abnormal
hardness of the cervix. Late lesions appear as fungating, ulcerated areas, which
destroy the cervix.
The vast majority of carcinomas of the cervix are squamous cell carcinomas,
arising from the transformation zone or ectocervix. Lesions fall into three
histological patterns: keratinizing squamous cell carcinoma, non-keratinizing
large-cell squamous carcinoma, and non-keratinizing small-cell squamous
Prognosis of squamous cell carcinoma of the cervix is related to stage at
The common presenting symptom is vaginal bleeding in the early stages, but
advanced neglected tumours may cause urinary obstruction due to bladder
The histological type of the tumour is less important for prognosis than is the
staging at diagnosis. Microinvasive carcinomas show minute foci of very
superficial invasion, only detected histologically, and have a very good
prognosis after local excision. Invasive carcinomas are staged according to the
degree of local invasion, and survival is related to stage. Invasion of
paracervical and external iliac nodes occurs early.
Interested in translating health topics to somali language!
We give here simplified and accurate information about the disease
DISCLAIMER: This website is provided for
general information and it's run by medical students for medical students only
and is not a substitute for professional medical advice. We are not responsible
or liable for any diagnosis or action made by a user based on the content of
this website. We are not liable for the contents of any external websites
listed, nor do we endorse any commercial product or service mentioned or advised
on any of the sites. Always consult your own doctor if you are in any way
concerned about your health