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The human papilloma virus (HPV)
plays a vital role in the pathogenesis of cervical disease.
Here follows a detailed discussion on the virus and its effects.
The recognition of condylomata dates back to Roman times.
Today HPV represents the most common symptomatic viral sexually
transmitted disease (STD) in the United States. HPV belongs
to the family of papouaviruses and is composed of a nonenveloped
icosahedral, doublestranded DNA virus. The papillomaviruses
are highly host specific and are characterized by an ability
to infect and transform epithelial cells, producing characteristic
histologic features.
The annual incidence of HPV infections has risen dramatically
over the past three decades. The exact incidence and prevalence
are unknown, since this is not a reportable disease, but there
are thought to be at least 500,000 cases per annum. The rise
could be attributed in part to increased hormonal versus barrier
method use, as well as the lack of specific antiviral therapy.
Up to 50% of sexually active young women and 60% to 80% of
male partners are infected with HPV. HPV is ubiquitous, and
the majority of the population may be exposed to it by adolescence
or early adulthood when sexual activity begins. Unfortunately,
there is less partner tracing done than for other STDs. HPV
is a chronic contagious disease, which is marked by dormant
stages with intermittent reactivation. The virus exhibits
latency patterns within human tissue. Clinical disease represents
only the tip of the iceberg! Subclinical disease is 10 times
more common then the presence of overt lesions.
HPV has gained notoriety because of its role in causing cervical
cancer. It is associated with an increased risk for dysplasia
and neoplasia. Almost all women with cervical cancer are infected
with HPV, but most women with HPV infections will not develop
carcinoma. However, the knowledge that certain HPV types are
causally linked to cervical cancer has been difficult to apply
in the clinical setting. When the link between HPV and cervical
cancer was first described, it appeared important to treat
low-grade cervical lesions aggressively. Now it is clear that
most of these lesions either remain stable or eventually regress.
More than 80 distinct HPV types have been identified. Types
are differentiated based on DNA homology or sequence and are
broadly categorized as to their ability to cause malignant
changes. Patients are often infected with more than one subtype.
Each of the HPV genotypes has a predilection for a number
of mucosal sites and is associated with a particular set of
clinicopathologic entities. HPV 1 and 2 subtypes are associated
with plantar and digital warts. HPV 3 and 10 subtypes are
often found in association with flat warts. The most frequent
subtypes found in genital disease include 6, 11, 16, and 18.
HPV 6 and 11 are linked to genital warts/condylomata acuminata,
low-grade squamous intraepithelial lesion (LGSIL) and respiratory
papillomatosis in neonates. High-risk types include 16, 18,
31, and 45 and are associated with high grade squamous intra-epithelial
lesions (HGSIL) and cervical cancer. DNA from high-risk HPV
subtypes is present in more than 85% of squamous cell carcinomas
of the cervix. Testing kits are being developed for HPV typing
and tissue demonstration via DNA hybridization techniques
(polymerase chain reaction) to facilitate appropriate risk
stratification.
Other factors almost certainly act with HPV to produce cervical
cancer. These include tobacco abuse, early onset of sexual
activity, birth control pill use, pregnancy, ethnicity (e.g.,
Hispanics), number of sexual partners, alcohol or drug abuse,
steroid use, poor nutrition (decreased folic acid intake),
and other non-HPV STDs. Immunosuppression apparently favors
the persistence of precursor lesions and, if cancer develops,
may accelerate its course.
The incubation period of HPV is about 3 months, although
it can be much longer in certain cases. The classic lesion,
the genital wart, can be located on the vulva, vagina, perineum,
cervix, anus, or penis glans and in the periclitoral region.
Other variations of lesions exist and may be papillomatous,
macular, erosive, pigmented, and erythematous in appearance.
Most lesions are painless and often inobtrusive. Meisel's
earlier classification of colposcopic appearances of HPV infections
in the lower genital tract divided condylomata into the following
classes:
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Exophytic/florid
Detected with the naked eye
Epithelium has thick white surface with fingerlike projections
showing irregular surface contours
Regular capillary loops seen in each of these projectionsthe
most reliable diagnostic feature!
Early/spiked
Not usually visualized with naked eye
Irregular surface containing tiny spikes of tissue, called
asperities (projections)
These projections reflect light from the colposcope
No capillary loops seen in asperities, but punctation may
be present
Irregular surface with sharp border between it and the surrounding
normal tissue
May resemble cervical intraepithelial neoplasia (CIN).
Flat/inverted
Most HPV infections of lower genital tract are flat, acetowhite
lesions
Impossible to distinguish from intraepithelial neoplasia
Mosaicism or punctation, usually of fine type, may be present
If coarse vascular patterns are found, highly suspect for
intraepithelial neoplasia
Reid scoring system helpful in distinguishing HPV infection
from CIN
A further histologic typing differentiates between papillary,
spiked, flat, inverted, and atypical condylomata.
The diagnosis of HPV-associated exophytic lesions (condylomata)
of the vulva, vagina, and cervix requires no great expertise
and no special tests. However, confirmation that no intraepithelial
neoplasia is present should be sought by biopsy. Some condylomata
may be readily confused with true malignant lesions because
of their associated vascular changes. Subclinical HPV lesions
of the vagina and cervix are usually detected by cytology.
Transmission occurs mainly via sexual contact. The diagnosis
is based on cervical changes on the Papanicolaou (Pap) smear,
visual identification of condylomata on the genitalia, or
the typical HPV appearance on colposcopy. Autoinoculation
may potentially take place, but nonvenereal transmission is
extremely rare. Vertical transmission from mother to infant
is possible during parturition.
The LGSIL category includes cytoplasmic manifestations of
HPV infection previously called koilocytosis, koilocytotic
atypia, and condylomatous atypia, as well as mild dysplasia.
Koilocytosis refers to the specific cytopathic effect seen
with HPV, namely hyperchromatism, nuclear shrinkage, and perinuclear
vacuolization. Koilocytosis is the most specific histologic
marker for HPV infections, except in HPV subtypes 16 and 18,
where koilocytosis may be absent. Although many experts suggest
colposcopic evaluation of LGSIL, some advocate watchful waiting
and repeat Pap smears. The patients history and risk
factors, as well as her degree of compliance, should be taken
into account when deciding on the appropriate mode of evaluation
and follow-up.
The approach to HGSIL is generally less controversial. Colposcopy,
biopsy, and endocervical curettage (ECC) are recommended.
A possible loop electrical excision procedure (LEEP) cone
biopsy may be considered in certain cases. A number of recent
studies suggest that women with high-grade dysplasia of the
cervix are also at risk for invasive cancer of the vagina,
vulva, and anus, probably because of the contiguous spread
of HPV.
The natural history of HPV is even more obscure in men than
in women. Male partners of women with lesions caused by HPV
may have very small penile lesions, and partners oftenbut
not alwaysshare HPV types. It is unclear whether HPV-infected
males have a significantly elevated risk of penile cancer.
Treatment options are influenced by the size, extent, and
site of the lesions, as well as the individual's underlying
conditions. Spontaneous regression takes place in 20% to 30%
of cases. Treatment modalities for condylomata include cryotherapy,
application of podophyllin, trichloroacetic acid, or Aldara
cream, electrocautery, surgical removal, or laser therapy.
Warts often proliferate during pregnancy and may be treated
with trichloroacetic acid, but not with podophyllin.
No treatment modality succeeds in eradicating the virus,
and no form of treatment is consistently effective. The risk
for future development of dysplasia and neoplasia should not
be overlooked, and regular follow-up evaluations (e.g., Pap
smears, colposcopies, and possibly biopsies) should be strongly
encouraged. Condoms may offer some protection against transmission,
but partners may need to be evaluated too.
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