CHAPTER 16
Intraepithelial Disease of the Cervix, Vagina, and Vulva
KEY POINTS
1 The criteria for the diagnosis of intraepithelial neoplasia may vary according to the
pathologist, but the significant features are cellular immaturity, cellular
disorganization, nuclear abnormality, and increased mitotic activity.
2 Metaplasia advances from the original squamocolumnar junction (SCJ) inward,
toward the external os and over the columnar villi to establish the transformation
zone. Cervical intraepithelial neoplasia (CIN) typically originates in the
transformation zone at the advancing SCJ.
3 Infection with human papillomavirus (HPV) is the primary cause of cancer of the
cervix and its precursor lesions. Persistent high-risk oncogenic HPV infection is the
principal risk factor for the development of CIN. In the vast majority of cases, HPV
infection will clear in 9 to 15 months.
4 Specific high-risk HPV types account for about 90% of high-grade intraepithelial
lesions and cancer (HPV-16, -18, -31, -33, -35, -39, -45, -51, -52, -56, -58, -59, and
-68). HPV-16 is the most common HPV found in invasive cancer and in CIN 2 and
CIN 3. Malignant transformation requires the expression of E6 and E7 HPV
oncoproteins.
5 High-risk HPV testing is a critical component of the triage for equivocal (ASC-US)
cytology, as a component of co-testing with simultaneous cytology, and as a standalone primary screening modality.
6 Evidence-based guidelines recommend that cervical cancer screening not begin until
age 21 years, regardless of sexual history. For women 21 to 29 years, the
recommendation is screening with cytology every 3 years. From 30 to 65 years cotesting with conventional cytology and high-risk HPV testing every 5 years or
cytology alone every 3 years are appropriate alternatives. After the age of 65 it is
911appropriate to discontinue screening in women with a negative screening history as
documented by either 3 negative cytology results or 2 negative co-tests in the
previous 10 years.
7 The usefulness of high-risk HPV testing in the assessment of atypical squamous cells
of unknown significance (ASC-US) Pap test results is well established, and aids in
the identification of 90% of the patients with CIN 2 or 3 lesions.
8 Women with atypical squamous cells-high grade (ASC-H) should be referred to
colposcopy because of the underlying risk of CIN 2 and/or 3, and should not be
triaged with high-risk HPV testing.
9 Colposcopy is required for the evaluation of a low-grade squamous intraepithelial
lesion (LSIL) cytology. Any woman with a cytology consistent with high-grade
squamous intraepithelial lesion (HSIL) must undergo colposcopy and directed
biopsy.
10 The minimum elements of a comprehensive colposcopic examination include
visualization of squamocolumnar junction, identification of acetowhitening or other
lesion(s), and an overall colposcopic impression (normal/benign, low grade, high
grade, cancer).
11 It is a best practice for pathologists and colposcopists to review jointly the
colposcopic examination findings, cytology, molecular testing, cervical biopsy, and
endocervical sampling in order to develop a therapeutic and surveillance plan.
12 The evidence-based guidelines for the management of cervical cytologic and
histologic entities lend themselves to structured clinical algorithms that are available
for download from the Web (www.asccp.org), on various mobile phone
applications, and may be incorporated into a variety of electronic health record
platforms.
13 CIN 1 is a histopathologic manifestation of HPV infection, not a cancer precursor.
For CIN 1 that persists for 24 months or more, a patient with an adequate
colposcopic examination may be given the choice of continued surveillance or
destruction of the transformation zone with ablation or excision.
14 CIN 2 and CIN 3 lesions are neoplastic precursors and grouped for the purposes of
diagnostic reporting and treatment. Women, 25 years of age and older, with
adequate colposcopy and histologic documentation of CIN 2 and/or CIN 3 require
destruction or excision of the transformation zone.
15 Although CIN 2 and CIN 3 can be treated with a variety of outpatient techniques,
the preferred treatment is LEEP. Ablative therapy using cryotherapy, laser ablation,
or any other technique is not appropriate if there is evidence of microinvasive or
invasive cancer on cytology, colposcopy, endocervical curettage (ECC), or biopsy.
16 Adenocarcinoma in situ (AIS) is a cancer precursor, and the preferred management
for women who have completed childbearing and have a histologic diagnosis of AIS
on a specimen from a diagnostic excisional procedure is hysterectomy.
17 Loop excision should not typically be used before a high-grade intraepithelial lesion
is identified with histopathology. However, treatment after an HSIL cytology may
912be appropriate among populations for whom colposcopic follow-up is not possible.
18 Conization is indicated for diagnosis in women with CIN 3 or atypical glandular cell
(AGC)-adenocarcinoma in situ, but hysterectomy is the treatment of last resort for
recurrent high-grade CIN.
19 Women with persistent abnormal cytology without evident cervical pathology and
those with abnormal cytology after treatment of CIN should be examined carefully
for vaginal intraepithelial neoplasia (VAIN). VAIN 1/HPV or VAIN 2 does not
require treatment and may be managed with surveillance. VAIN 3 lesions that are
adequately sampled to rule out invasive disease can be treated with laser therapy or
excisional therapy.
20 Vulvar intraepithelial neoplasia (VIN) 3 is a neoplastic precursor and can be
unifocal or multifocal. The therapeutic alternatives for VIN 3 are simple excision,
laser ablation, and superficial vulvectomy.
CERVICAL INTRAEPITHELIAL NEOPLASIA
The concept of preinvasive disease of the cervix was introduced in 1947, when
pathologists identified features suggestive of invasive cancer but confined to
epithelium (1). Subsequent studies showed that these lesions left untreated could
progress to cervical cancer (2). Improvements in cytologic assessment led to the
identification of early precursor lesions known as dysplasia, a term that connotes
the malignant potential of these lesions. Historically, carcinoma in situ (CIS) was
treated very aggressively (most often with hysterectomy), whereas dysplasias
were believed to be less significant and were not treated or were treated by
colposcopic biopsy and cryosurgery. The concept of cervical intraepithelial
neoplasia (CIN) was introduced in 1968, when Richart suggested that dysplasias
have the potential for progression (3). [1] The criteria for the diagnosis of
intraepithelial neoplasia may vary according to the pathologist, but the
significant features are cellular immaturity, cellular disorganization, nuclear
abnormality, and increased mitotic activity. The extent of the mitotic activity,
immature cellular proliferation, and nuclear atypia identifies the degree of
neoplasia. If the presence of mitoses and immature cells is limited to the lower
third of the epithelium, the lesion usually is designated as CIN 1. Involvement of
the middle and upper thirds is diagnosed as CIN 2 and CIN 3, respectively (Fig.
16-1).
Cervical Anatomy
The cervix is composed of columnar epithelium, which lines the endocervical
canal, and squamous epithelium, which covers the exocervix (4). The point at
which they meet is called the squamocolumnar junction (SCJ) (Figs. 16-2 and 16-
9133).
The Squamocolumnar Junction
The SCJ is not restricted to the external os. Instead, it is a dynamic point that
changes in response to puberty, pregnancy, menopause, and hormonal stimulation
(Fig. 16-4). In neonates, the SCJ is located on the exocervix. At menarche, the
production of estrogen causes the vaginal epithelium to fill with glycogen.
Lactobacilli act on the glycogen to lower the pH, stimulating the subcolumnar
reserve cells to undergo metaplasia (4).
[2] Metaplasia advances from the original SCJ inward, toward the external
os and over the columnar villi to establish the transformation zone. The
transformation zone extends from the original SCJ to the physiologically active
SCJ, as demarcated by the SCJ. As the metaplastic epithelium in the
transformation zone matures, it begins to produce glycogen and eventually
resembles the original squamous epithelium, both colposcopically and
histologically (Fig. 16-5A,B).
CIN typically originates in the transformation zone at the advancing SCJ.
The anterior lip of the cervix is twice as likely to develop CIN as the posterior lip,
and CIN rarely originates in the lateral angles. Once CIN occurs, it can progress
horizontally to involve the entire transformation zone, but it usually does not
replace the original squamous epithelium. This progression usually results in CIN
with a sharp external border. Proximally, CIN involves the cervical clefts, and this
area tends to have the most severe CIN lesions. The extent of involvement of
these cervical glands has significant therapeutic implications since the entire
gland must be destroyed to ensure elimination of the CIN (4). The only way to
determine where the original SCJ was located is to look for nabothian cysts or
cervical cleft openings, which indicate the presence of columnar epithelium. After
the metaplastic epithelium matures and forms glycogen, it is called the healed
transformation zone and is relatively resistant to oncogenic stimuli.
914FIGURE 16-1 Diagram of cervical intraepithelial neoplasia compared with normal
epithelium.
The entire SCJ with early metaplastic cells is susceptible to oncogenic factors,
which may cause these cells to transform into CIN. Changes associated with CIN
are most likely to begin either during menarche or after pregnancy, when
metaplasia is most active. Conversely, after menopause a woman undergoes little
metaplasia and is at a lower risk of developing CIN from de novo human
papillomavirus (HPV) infection. HPV infection occurs through sexual contact in
general and intercourse in particular. Although several agents, including sperm,
seminal fluid histones, trichomonas, chlamydia, and herpes simplex virus, were
studied, it is well established that persistent high-risk oncogenic HPV infection
is the overwhelming risk factor for the development of CIN.
915FIGURE 16-2 The cervix and the transformation zone.
Normal Transformation Zone
916FIGURE 16-3 Diagram of the cervix and the endocervix.
The original squamous epithelium of the vagina and exocervix has four layers (4):
1. The basal layer is a single row of immature cells with large nuclei and a small
amount of cytoplasm.
2. The parabasal layer includes two to four rows of immature cells that have
normal mitotic figures and provide the replacement cells for the overlying
epithelium.
3. The intermediate layer includes four to six rows of cells with larger amounts
of cytoplasm in a polyhedral shape separated by an intercellular space.
Intercellular bridges, where differentiation of glycogen production occurs, can
be identified with light microscopy.
4. The superficial layer includes five to eight rows of flattened cells with small
uniform nuclei and a cytoplasm filled with glycogen. The nucleus becomes
pyknotic, and the cells detach from the surface (exfoliation). These cells form
the basis for Papanicolaou (Pap) testing more accurately known as cervical
cytology.
917FIGURE 16-4 Different locations of the transformation zone and the squamocolumnar
junction during a woman’s lifetime. The arrows mark the active transformation zone. The
blue arrows indicate internal boundaries of SCJ. The white arrows indicate external
boundaries of the SCJ.
918919FIGURE 16-5 A: Active metaplasia in the transformation zone. B: Maturing metaplasia in
the transformation zone.
Columnar Epithelium
Columnar epithelium has a single layer of columnar cells with mucus at the top
and a round nucleus at the base. The glandular epithelium is composed of
numerous ridges, clefts, and infoldings and, when covered by squamous
metaplasia, leads to the appearance of gland openings. Technically, the
endocervix is not a gland, but often the term gland openings is used.
Metaplastic Epithelium
Metaplastic epithelium, found at the SCJ, begins in the subcolumnar reserve cells.
Under stimulation of lower vaginal acidity, the reserve cells proliferate, lifting the
columnar epithelium. The immature metaplastic cells have large nuclei and a
small amount of cytoplasm without glycogen. As the cells mature normally, they
produce glycogen, eventually forming the four layers of epithelium. The
metaplastic process begins at the tips of the columnar villi, which are exposed
first to the acid vaginal environment. As the metaplasia replaces the columnar
epithelium, the central capillary of the villus regresses, and the epithelium flattens
out, leaving the epithelium with its typical vascular network. As metaplasia
proceeds into the cervical clefts, it replaces columnar epithelium and similarly
flattens the epithelium. The deeper clefts may not be completely replaced by the
metaplastic epithelium, leaving mucus-secreting columnar epithelium trapped
under the squamous epithelium. Some of these glands open onto the surface;
others are completely encased, with mucus collecting in nabothian cysts. Gland
openings and nabothian cysts mark the original SCJ and the outer edge of the
original transformation zone (Fig. 16-5A,B) (4).
920FIGURE 16-6 Cervical intraepithelial neoplasia grade 1 (CIN 1) with koilocytosis. The
normal maturation process and differentiation from the basal and parabasal layers to the
intermediate and superficial layers are maintained. In the upper layers, koilocytes are
characterized by perinuclear halos, well-defined cell borders, and nuclear hyperchromasia,
irregularity, and enlargement.
Human Papillomavirus
The cytologic changes of HPV were first recognized by Koss and Durfee in 1956
and given the term koilocytosis (5). Their significance was not recognized until 20
years later, when Meisels et al. reported these changes in mild dysplasia (Fig. 16-
6) (6). Molecular biologic studies showed high levels of HPV DNA and capsid
antigen, indicating productive viral infection in these koilocytic cells (7). HPVrelated changes are found in all grades of cervical neoplasia (8). [3] Infection
with HPV is the primary cause of cancer of the cervix and its precursor
lesions (9). As the CIN lesions become more severe (Fig. 16-7), the koilocytes
disappear, the HPV copy numbers decrease, and the capsid antigen disappears,
indicating that the virus is not capable of reproducing in less differentiated cells
(10). Instead, portions of the HPV DNA become integrated into the host cell.
Integration of the transcriptionally active DNA into the host cell appears to be
essential for malignant transformation (11). Malignant transformation requires
921the expression of E6 and E7 HPV oncoproteins (12). Because HPV will not
grow in cell culture, there is no direct evidence of the carcinogenesis of HPV.
However, a cell culture system for growing keratinocytes was described that
allows for stratification and differentiation of specific keratinase types (13). When
normal cells are transfected with the plasmid-containing HPV-16, the transfected
cells produce cytologic abnormalities identical to those seen in intraepithelial
neoplasia. The E6 and E7 oncoproteins are identifiable in the transfected cell
lines, providing strong laboratory evidence of a cause-and-effect relationship (14).
Cervical cancer cell lines that contain active copies of HPV-16 or -18 (SiHa,
HeLa, C 4–11, Ca Ski) express HPV-16 E6 and E7 oncoproteins (15).
HPV DNA can be detected in the overwhelming majority of women with
cervical neoplasia (16,17). There are more than 120 types of HPV identified, with
30 of these HPV types primarily infecting the squamous epithelium of the lower
anogenital tract of men and women (18,19). Detection of HPV is associated with
a 250-fold increase in risk of high-grade CIN (20). The percentage of
intraepithelial neoplasia attributed to HPV infection approaches 90% (17).
Specific high-risk HPV types account for about 90% of high-grade
intraepithelial lesions and cancer (HPV-16, -18, -31, -33, -35, -39, -45, -51,
-52, -56, -58, -59, and -68) (17). [4] HPV-16 is the most common HPV found
in invasive cancer and in CIN 2 and CIN 3 (21). It is the most common HPV
type found in women with normal cytology.
HPV-16 infection is not a very specific finding and can be found in 16% of
women with low-grade lesions and in up to 14% of women with normal cytology.
HPV type-18 is found in 23% of women with invasive cancers, 5% of women
with CIN 2 and CIN 3, 5% of women with HPV and CIN 1, and fewer than 2% of
patients with negative findings (17). Therefore, HPV-18 is more specific than
HPV-16 for invasive tumors.
Usually, HPV infections are typically transient and those that do persist may
remain latent for many years. Most women who are exposed have no clinical
evidence of disease, and the infection is eventually suppressed or eliminated (16).
Other women exhibit low-grade cervical lesions that mostly regress
spontaneously. [3] In the vast majority of cases, HPV infection will clear in 9
to 15 months (22). A small minority of women exposed to HPV develops
persistent infection that may progress to CIN (16,23). Persistent high-risk HPV
infection increases the risk of high-grade disease 300-fold and is required for the
development and maintenance of CIN 3 (24,25). Factors that may have a role in
persistence and progression include smoking, contraceptive use, infection with
other sexually transmitted diseases, or nutrition (16,21). Any factor that
influences the integration of HPV DNA into the human genome may contribute to
progression to invasive disease (26).
922FIGURE 16-7 Cervical biopsy showing normal cells, cervical intraepithelial neoplasia 2
and 3 (CIN 2, CIN 3). In CIN 3, the normal maturation is lost.
Screening
Cervical Cytology
Cervical cytology has been the mainstay of cervical cancer screening since the
mid-20th century. Its terminology has evolved to reflect an evolving and
improved understanding of the pathogenesis of HPV-related disease in the lower
genital tract. In 1988, the first National Cancer Institute (NCI) workshop held in
Bethesda, Maryland, resulted in the development of the Bethesda System for
cytologic reporting. That standardized method of reporting cytology findings
facilitated peer review and quality assurance and was updated and refined in the
Bethesda III System (2001) (Table 16-1).
According to this system, potentially premalignant squamous lesions fall into
specific categories: (i) atypical squamous cells (ASC), (ii) low-grade squamous
intraepithelial lesions (LSILs), and (iii) high-grade squamous intraepithelial
lesions (HSILs) (27). The ASC category is subdivided into two categories: those
of unknown significance (ASC-US) and those in which high-grade lesions must
be excluded (ASC-H). LSILs include CIN 1 (mild dysplasia) and the changes of
923HPV, termed koilocytotic atypia. The HSIL category includes CIN 2 and CIN 3
(moderate dysplasia, severe dysplasia, and CIS). The terminology, AGUS, or
atypical glandular cells of undetermined significance, was developed to
characterize evidence of nonsquamous glandular neoplasia originating in the
cervix.
Cellular changes associated with HPV (i.e., koilocytosis and CIN 1) are
included within the category of LSIL because the natural history, distribution of
various HPV types, and cytologic features are the same (26). Histopathologic and
molecular virologic correlation showed a similar heterogeneous distribution of
low- and high-risk HPV types in both koilocytosis and CIN 1 (28,29). On the
basis of clinical behavior, molecular biologic findings, and morphologic features,
HPV changes and CIN 1 are the same disease. The rationale for combining CIN 2
and CIN 3 into the category of HSIL is similar. The biologic studies reveal a
comparable mix of high-risk HPV types in the two lesions, and the separation of
the lesions is not reproducible (29,30). The management of CIN 2 and CIN 3 is
similar.
Cervical Cytologic Screening Test Accuracy
Screening for cervical cancer precursors using exfoliative cervicovaginal
cytology, the Pap test, was successful in reducing the incidence of cervical cancer
by 79% and the mortality by 70% since 1950 (31). The annual incidence rate
dropped from 8 to 5 cases per 100,000 women, so approximately 8,200 women
per year are diagnosed with cervical cancer (31–33). A literature review of
cervical cytology testing techniques was conducted by the Agency for Healthcare
Research and Quality (34). The conclusion was that the sensitivity of
conventional cytologic testing in detecting cervical cancer precursor lesions was
51%, with an estimated false-negative rate of 49%. In three reviews of the
accuracy of cervical cytology assessment, the sensitivity of the cervical cytology
for the detection of CIN 2 or 3 ranged from 47% to 62% and the specificity
ranged from 60% to 95% (35–37). More than half of all cases of invasive
cancer occur in women who were never screened or who were underscreened.
The causes of missed cases of cervical cancer in women who have been screened
are errors of sampling, fixation, interpretation or lack of follow-up (38).
Conventional cytology has improved in order to reduce false-negative errors.
Sampling errors occur because a lesion is too small to exfoliate cells or the device
did not pick up the cells and transfer them to the fixation media. Historically,
preparation errors occurred because of poor fixation on the glass slide, leading to
air drying and its consequences for interpretation. The slide preparations could be
too thick and obscured by vaginal discharge, blood, or mucus. These problems
were obviated with the widespread utilization of liquid-based media. Interpretive
924errors have been reduced by the large scale implementation of automated
detection devices that assist the cytotechnologist in identifying significant cellular
abnormalities. The ubiquitous use of liquid-based medium to collect the cytologic
sample and preserve the collected cervical cells significantly decreased specimen
sampling and preparation errors. With this technique, liquid samples are
processed to provide a uniform, thin layer of cervical cells without debris on a
glass slide. The cell sample is collected with an endocervical brush used in
combination with a plastic spatula or with a plastic broom. The sample is rinsed
in a vial containing liquid alcohol-based preservative. With this technique, 80% to
90% of the cells are transferred to the liquid media, as compared with the 10% to
20% transferred to the glass slide with conventional cytologic testing. Use of
liquid-based media eliminates air drying. The cells are retrieved from the vial by
passing the liquid through a filter, which traps the larger epithelial cells,
separating them from the small blood and inflammatory cells. This process yields
a thin layer of diagnostic cells properly preserved and more easily interpreted by
the cytologist. This technique reduces by 70% to 90% the rate of unsatisfactory
samples encountered with conventional cytologic testing (39). Liquid-based
cytology is commonly performed by most of the laboratories in the United States.
Another technology approved by the Food and Drug Administration (FDA) for
primary screening and rescreening samples of cervical cytology initially
interpreted as normal is the automated image-guided slide screening system. This
technique uses an automated microscope coupled to a special digital camera. The
system scans the slide and uses computer imaging techniques to analyze each
field of view on the slide. Computer algorithms rank each slide on the probability
that the sample may contain an abnormality. The selected slides are reviewed by a
cytotechnologist or cytopathologist. This technique reduced the false-negative
rate by 32% (40).
Human Papillomavirus Testing in Screening
An improved understanding of the critical role of high-risk human papillomavirus
infection in the development of cervical cancer and its precursors has generated
the proliferation of molecular tools that have come into clinical practice. Such
methods have undergone extensive clinical trials, have been submitted to the
rigorous approval process of the FDA, and have resulted in their licensure for
specific roles in the screening process. [5] High-risk HPV testing is a critical
component of the triage for equivocal (ASC-US) cytology, as a component of
co-testing with simultaneous cytology, and as a stand-alone primary
screening modality (Table 16-2).
Cervical Cancer Screening Recommendations
925Guidelines based on the literature were developed to guide cervical cancer
screening, follow-up, and treatment. The evolving state of the science and our
improved understanding of HPV and cervical carcinogenesis, and clinical practice
and liability considerations, occasionally lead to subtle differences in the
interpretation of these guidelines. Ultimately, guidelines cannot substitute for an
informed discussion of risks and benefits between a patient and health care
provider in order to make decisions about treatment.
The American College of Obstetricians and Gynecologists (ACOG) updated its
guidelines (41). [6] The ACOG recommends that women not initiate cervical
cancer screening until they are 21, regardless of the onset of sexual activity. This
acknowledges the very low prevalence of invasive cancer in very young women,
the long multiyear process of cervical carcinogenesis, and the very low but real
risks for preterm birth associated with outpatient excisional procedures. Likewise,
screening frequency was revised to every 2 years from ages 21 to 29 (with either
conventional slide or liquid-based cytology), and every 3 years for women after
age 30 years if 3 consecutive negative, that is, negative for intraepithelial lesion or
malignancy (NILM) Pap tests can be documented. More frequent screening
continues to be recommended for HIV-positive women (twice first year and
annually after), those who are immune suppressed, diethylstilbestrol (DES)
daughters, and for those with a history of CIN 2 or greater (screen annually for 20
years). Discontinuation of screening is reasonable between 65 and 70 years, with
reassessment of risk factors annually to determine if reinitiating screening is
appropriate. Likewise, in the setting of posthysterectomy for benign indications it
is reasonable to discontinue screening in the absence of a history of high-grade
CIN or cancer (Table 16-3).
Table 16-2 Commercially Available High-Risk HPV Assays and Their FDAApproved Clinical Indications
926Table 16-3 Comparison of Screening Guidelines From the American Cancer Society,
American Society of Colposcopy and Cervical Pathology and American
Society Clinical Pathology, the American College of Obstetricians and
Gynecologists, and the U.S. Preventive Services Task Force
The 2011 American Society for Colposcopy and Cervical Pathology (ASCCP),
American Cancer Society (ACS), and the American Society for Clinical
Pathology (ASCP) co-convened a guidelines development process in
collaboration with more than 21 partner organizations. The goal of this process
was to develop a set of updated evidence-based screening guidelines that reflected
our best understanding of the science (42). Contemporaneously and independent
of this effort the U.S. Preventive Services Task Force (USPSTF) is using an
entirely different methodology and on the basis of an independent systematic
evidence review in the process of updating that entity’s cervical cancer screening
recommendations (43). These near-parallel processes produced a set of
remarkably concordant recommendations whose uniformity has been beneficial to
patients and clinicians.
[6] These evidence-based guidelines recommend that cervical cancer
screening not begin until age 21 years, regardless of sexual history. For
women 21 to 29 years, the recommendation is screening with cytology every
3 years. From 30 to 65 years co-testing with conventional cytology and highrisk HPV testing every 5 years or cytology alone every 3 years are
appropriate alternatives. After the age of 65 it is appropriate to discontinue
screening in women with a negative screening history as documented by
either 3 negative cytology results or 2 negative co-tests in the previous 10
years (42,43).
927The USPSTF published its updated draft guidelines and made them available
for stakeholder input (Table 16-3). The major and historic innovation is the
unprecedented incorporation of primary screening using molecular high-risk HPV
testing (as an alternative to cytology every 3 years) in women between 30 and 65
years.
Atypical Squamous Cells
The ASC category does not include benign, reactive, and reparative changes,
classified as normal in the Bethesda system. This cytologic diagnosis is relatively
common, ranging from 3% to 25% in some centers (44). When standardized
diagnostic criteria are used, the rate of ASC results should be 3% to 5% (45). The
ASC category is subdivided into ASC-US and ASC-H.
The cytologic diagnosis of ASC-US is associated with a 10% to 20% incidence
of CIN 1 and a 3% to 5% risk for CIN 2 or 3 (46–49). CIN 1 is most often a
benign HPV infection and will regress spontaneously in more than 60% of cases;
therefore, the goal of triage of an ASC-US Pap test result is to identify more
advanced CIN 2 and CIN 3 lesions (50).
Immediate colposcopy is assumed to be the most sensitive method of detecting
CIN 2 or 3 (46,49). Because 80% of patients will not have significant lesions, it is
important to avoid overinterpretation of the colposcopic findings. [7] The
usefulness of high-risk HPV testing in the assessment of ASC-US Pap test
results (51–53) is well established, and aids in the identification of 90% of the
patients with CIN 2 or 3 lesions. To compare the aforementioned triage method
in a prospective, randomized fashion, the NCI funded an ASC-US/LSIL Triage
Study (ALTS) (54). Patients with ASC-US or LSIL were randomized to three
triage arms: (i) immediate colposcopy, (ii) HPV test, and (iii) conservative
management by repeat Pap test. There were 1,163 women in the immediate
colposcopy group, and 14 refused the examination. The results of colposcopy are
assumed to reflect the prevalent disease rates, which were as follows: CIN 1,
14.3%; CIN 2, 16.1%; and CIN 3, 5%. Thus, 75% of the women with ASC-US
had negative colposcopy results and either did not have a biopsy (25%) or had a
biopsy with negative results. The HPV test results were positive in 56.1% of the
patients, and 6.1% of the patients did not return for colposcopy. Of the 494 who
underwent colposcopy, the results were as follows: CIN 1, 22.5%; CIN 2, 11.9%;
and CIN 3, 15.6%. The sensitivity of HPV test was 95.9% for the detection of
CIN 2 and 96.3% for the detection of CIN 3.
In the conservatively managed group, only one follow-up cytology was
reported. The results of the single follow-up Pap test were included. Using a
cutoff that includes any positive finding of ASC-US or greater, the sensitivity is
85% for CIN 2 and 85.3% for CIN 3, with 58.6% of patients referred for
928colposcopy. If LSIL is used as a cutoff, 26.2% of the patients are referred, with
sensitivity of 64.0% for both CIN 2 and CIN 3. Using HSIL as the cutoff, 6.9%
are referred, and the sensitivity falls to 44%. The conclusion of the ALTS trial is
that HPV triage is highly sensitive in identifying CIN 2 and CIN 3 lesions and
that it cuts the rate of referral for colposcopy by approximately one-half (55).
When mathematical models are used to simulate the natural history of HPV and
cervical cancer in a cohort of US women, a 2- to 3-year screening strategy using
cytology with reflex high-risk HPV triages is more effective and less costly in
reducing the rate of cancer than annual conventional cytology (56).
[8] Women with ASC-H should be referred to colposcopy because of the
underlying risk of CIN 2 and/or 3, and should not be triaged with high-risk
HPV testing.
Low-Grade Squamous Intraepithelial Lesions
The cytologic diagnosis of LSIL is reproducible and accounts for 1.6% of
cytologic diagnoses (45). About 75% of the patients have CIN, with 20% being
CIN 2 or 3 (46–48). These patients require additional evaluation. The ALTS trial
closed the HPV test arm early because the HPV positivity rate was 82% and was
not a valid discriminator in determining the presence of disease. The ALTS trial
found that a cytology interpretation of LSIL is associated with a 25% risk of
histologic CIN 2 or 3 within 2 years. No effective triage strategy was identified to
spare many women from colposcopic referral without increasing their risk of CIN
3 and invasive carcinoma (57). [9] Guidelines reaffirm the appropriateness of
colposcopy to evaluate after an LSIL cytology (52).
High-Grade Squamous Intraepithelial Lesions
[9] Any woman with a cytologic specimen suggesting the presence of HSIL
must undergo colposcopy and directed biopsy (52). Two-thirds of patients with
this cytologic finding will have CIN 2 or greater. After colposcopically directed
biopsy and determination of the distribution of the lesion, excisional or ablative
therapy that addresses the entire transformation zone should be performed. For
populations who have completed childbearing and who are likely to be lost to
follow-up, outpatient excision of the transformation may be considered after this
cytologic diagnosis.
Colposcopic Diagnosis
The ASCCP convened a process to develop evidence-based and expert consensus
recommendations for the practice of colposcopy in the United States (58). An
outcome of this process was the development of standardized terminology for
929findings at colposcopic examination (59). It described [10] the minimum
elements of a comprehensive colposcopic examination, which include
visualization of SCJ, the identification of acetowhitening or other lesion(s),
and an overall colposcopic impression (normal/benign, low grade, high
grade, cancer) (Table 16-4) (59,60).
Table 16-4 Essential Elements of a Colposcopic Examination (Adapted from ASCCP)
Component Content
Precolposcopic
assessment
Evaluate/document the following: Indication; history of prior
screening tests, colposcopy, and treatment; parity, contraception,
pregnancy, menopause, hysterectomy, smoking, HIV, HPV
vaccination.
Informed consent.
Examination Gross assessment of the vulva, vagina, perianal area, and cervix.
Examination of the cervix and upper vagina with magnification after
application of 3–5% acetic acid using white light and green/blue filter.
Documentation Document cervix visibility, and visualization of squamocolumnar
junction.
Document (using diagram or photography) findings including
presence, location, size, appearance, and characteristic of the lesion.
Colposcopic impression.
Tissue
sampling
Perform/document biopsy type, location of lesions.
Perform/document endocervical sampling.
Postprocedure Document modality and timing of how patient will be notified.
The guidelines formalize the practice of risk-based colposcopy. In general,
colposcopists are asked to consider at least two and up to four biopsies of all
suspected lesions (61). For women at the lowest risk of high-grade disease (those
with less than HSIL cytology, no evidence for HPV16/18, and a normal
colposcopic impression), random non-targeted biopsies are not recommended.
Conversely, nonpregnant women at the greatest risk of disease may merit a more
aggressive diagnostic workup.
The p16 protein is a cell cycle regulator, and under physiologic conditions, p16
acts as an inhibitor of cyclin-dependent kinases CDK4 and CDK6; this leads to
cell cycle arrest in epithelial cells undergoing cellular differentiation. However, in
response to a transforming infection by high-risk human papillomavirus (hrHPV)
930with overexpression of oncogenic protein E7, p16 levels rise. The excess p16 is
thus a surrogate marker of the transforming HPV infection. p16 is
recommended for use as an adjudication tool for cases in which there is a
professional disagreement in histologic specimen interpretation, with the
caveat that the differential diagnosis includes a precancerous lesion (CIN 2/-
IN2 or CIN 3/-IN3) (62,63).
The 2012 ASCCP consensus guidelines recommended grouping CIN 2 and
CIN 3 together as high-grade histology. However, it was recognized that
there was a subset of CIN 2 patients that would not progress and thus did not
need treatment. In 2012, the College of American Pathologists and ASCCP
cosponsored the Lower Anogenital Squamous Terminology (LAST)
standardization project and published the LAST recommendations for
histopathology reporting of HPV-related squamous lesions of the lower
anogenital tract. Specifically LAST calls for the use of a 2-tier nomenclature
(low-grade squamous intraepithelial lesion/high-grade squamous
intraepithelial lesion [LSIL/HSIL]) and expanded use of the biomarker p16
to classify equivocal lesions as either precancer (HSIL) or low-grade lesions
(LSIL)/non-HPV changes. In one study, among 166 patients with subsequent
pathology (including 131 excisions), 26.2% of p16-positive cases of grade 2
intraepithelial neoplasia versus 4.4% of p16-negative cases were associated with a
subsequent diagnosis of HSIL (-IN 3) or worse (P = 0.002) (64). The results
indicate that using the LAST recommendations would result in
approximately one-third of equivocal (-IN 2) diagnoses being downgraded to
LSIL over 1 year. The significant association of p16 expression with a higher
risk for HSIL on a subsequent specimen suggests that the use of p16 to
adjudicate equivocal (-IN 2) diagnoses in lower anogenital tract specimens as
either LSIL or HSIL would likely predict lesion grade more accurately and
avoid unnecessary excisional procedures. Therefore, strong and diffuse
block-positive p16 results support a categorization of precancerous disease.
Negative or non–block-positive staining strongly favors an interpretation of
low-grade disease or a non–HPV-associated pathology such as immature
squamous metaplasia, atrophy, or reparative changes. Subsequent
publications have confirmed the accuracy of p16 IHC (62,63).
Therefore, women with histologic diagnosis of CIN 2 with negative p16
staining have a very low risk of advancing to CIN 3 and no patient has
developed invasive cancer in these studies. These women can avoid
treatment, especially if they want further childbearing. Postmenopausal
women often have atrophy or reparative changes and they may benefit from
p16 testing as well.
931Colposcopy Findings
Colposcopic assessment is a critical component of the follow-up of the abnormal
cervical screening. Specialty providers in a variety of clinical settings have
historically performed this procedure. In an effort to improve the quality and
consistency of this procedure the American Society of Colposcopy and Cervical
Pathology has developed and disseminated a new set of standards for services in
this arena (59). This process developed standard terminology and definitions of
findings. Table 16-4 summarizes the essential elements of a colposcopic
evaluation.
Acetowhite Epithelium
Epithelium that turns white after application of acetic acid (3% to 5%) is called
acetowhite epithelium (34). The application of acetic acid coagulates the proteins
of the nucleus and cytoplasm and makes the proteins opaque and white (4).
The acetic acid does not affect mature, glycogen-producing epithelium because
the acid does not penetrate below the outer one-third of the epithelium. The cells
in this region have very small nuclei and a large amount of glycogen (not
protein). These areas appear pink during colposcopy. Dysplastic cells are those
most affected. They contain large nuclei with abnormally large amounts of
chromatin (protein). The columnar villi become “plumper” after acetic acid is
applied, making these cells easier to see. They appear slightly white, particularly
in the presence of metaplasia. The immature metaplastic cells have larger nuclei
and show some effects of the acetic acid. Because the metaplastic epithelium is
very thin, it is not as white or opaque as CIN but instead appears gray and filmy
(4).
Leukoplakia
Translated literally, leukoplakia is white plaque (4). This plaque is white
epithelium, visible before application of acetic acid. Leukoplakia represents a
layer of keratin on the surface of the epithelium. Immature squamous epithelial
cells have the potential to develop into keratin- or glycogen-producing cells. In
the vagina and on the cervix, the normal differentiation is toward glycogen.
Leukoplakia should not be confused with the white plaque of a monilial infection,
which can be completely wiped off with a cotton-tipped applicator.
Keratin production is abnormal in the cervicovaginal mucosa. Leukoplakia
results from this process and is commonly associated with HPV infection (Fig.
16-8) and related keratinizing intraepithelial or invasive lesions and should be
biopsied. Other etiologies for this lesion include chronic trauma from diaphragm,
pessary, or tampon use and radiotherapy.
Punctation
932Dilated capillaries terminating on the surface appear from the ends as a collection
of dots and are referred to as punctation (Fig. 16-9). When these vessels occur in
a well-demarcated area of acetowhite epithelium, they indicate an abnormal
epithelium—most often high-grade CIN (Fig. 16-10) (4). The punctate vessels are
formed as the metaplastic epithelium migrates over the columnar villi. Normally,
the capillary regresses; however, when CIN occurs, the capillary persists and
appears more prominent.
Mosaic
Terminal capillaries surrounding roughly circular or polygonal-shaped blocks of
acetowhite epithelium crowded together are called mosaic because of their
appearance (Fig. 16-11). These vessels form a “basket” around the blocks of
abnormal epithelium. They may arise from a coalescence of many terminal
punctate vessels or from the vessels that surround the cervical gland openings (4).
Mosaicism tends to be associated with high-grade lesions (CIN 2 and CIN 3)
(Figs. 16-12 and 16-13).
FIGURE 16-8 Colposcopy of cervical intraepithelial neoplasia 2 (CIN 2) associated with
human papillomavirus (HPV) infection of the cervix.
933The International Federation for Cervical Pathology and Colposcopy published
additional colposcopic criteria for CIN 3. They are ridge sign—dense acetowhite
extending along the cervical ridges, and inner border sign—thick acetowhite with
distinct border existing inside a finer, lacy acetowhite lesion (Fig. 16-14). These
are added to the previously described cuffed gland—dense acetowhite around the
gland openings, and rag sign—peeling of the epithelium in an area of acetowhite
(Fig. 16-15) (65).
Atypical Vascular Pattern
Atypical vascular patterns are characteristic of invasive cervical cancer and
include looped vessels, branching vessels, and reticular vessels.
FIGURE 16-9 Diagram of punctation. The central capillaries of the columnar villi are
preserved and produce the punctate vessels on the surface.
934FIGURE 16-10 Human papillomavirus (HPV)/cervical intraepithelial neoplasia 2 (CIN 2)
presents as a white lesion with surface spicules.
Clinical Pathologic Correlation
[11] It is a best practice for pathologist and colposcopist to jointly review the
colposcopic examination findings, cytology, molecular testing, cervical
biopsy, and endocervical sampling in order to develop a therapeutic plan.
Cytology results should not be sent to one laboratory and the histology results to
another. When the cytology, biopsy, and molecular testing results correlate, the
colposcopist can be reasonably certain that the most clinically significant lesion
was identified. If cytology indicates a more significant lesion than the histology,
the patient may require further evaluation, including repeat colposcopy, additional
biopsies, and excisional diagnostic procedures under certain circumstances.
Management
Clinical Disease Management Guidelines
In 2012, the ASCCP and the NCI sponsored a consensus conference to update
evidence-based guidelines for abnormal cervical cancer screening. This gathering
brought together 47 experts and 23 professional societies, national and
935international health organizations, and federal agencies to review the latest natural
history and clinical data, and consider how the newly updated cervical cancer
screening impacted the clinical follow-up of abnormal screens (66). [12] The new
comprehensive evidence-based guidelines for the management of cervical
cytologic and histologic entities lend themselves to structured clinical
algorithms that are available for download from the Web (www.asccp.org),
on various mobile phone applications, and can be incorporated into a variety
of electronic health record platforms.
CIN 1
[13] Although CIN 1 is a histopathologic manifestation of HPV infection, it is
not a cancer precursor. The spontaneous regression rate of biopsy-proven CIN 1
is conservatively estimated to be 60% to 85% in prospective studies and
regression typically occurs within a 2-year follow-up (4,52,67–70). Patients who
have biopsy-proven CIN 1 (after a cytologic finding of ASC, LSIL) with
satisfactory colposcopy are followed with cytology and high-risk HPV testing
(co-testing) at 12 months. With a negative cytology and high-risk HPV test at the
12-month follow-up these women can be returned to age-appropriate screening.
The patient is returned to colposcopy for appropriate reevaluation in the event of
abnormality on surveillance testing (66). Young women of ages 21 to 24 years in
this clinical scenario may undergo surveillance with repeat cytology only at 12
and 24 months, with referral to colposcopy for ASC-US or greater (66).
[14] For CIN 1 that persists 24 months or more, a patient with an adequate
colposcopic examination may be given the choice of continued surveillance or
destruction of the transformation zone with ablation or excision (66).
However, if colposcopy is inadequate, ablative therapy should be avoided.
Expectant management may not be appropriate for patients with chronic systemic
immunosuppression, such as those requiring steroids, chemotherapy, or
antirejection drugs, and others who may have persistent low-grade abnormalities
(52).
Clinical situations where biopsy histopathology is CIN 1 preceded by ASC-H
or HSIL cytology carry a higher risk. In these settings, follow-up with co-testing
(with cytology and high-risk HPV) at 12 and 24 months or loop excision
procedure may be more appropriate (66).
CIN 2 and CIN 3
Typically, CIN 2 and CIN 3 lesions are neoplastic precursors and grouped for
the purposes of diagnostic reporting and treatment. [14] Women, 25 years of
age and older, with adequate colposcopy and histologic documentation of
CIN 2 and CIN 3 require destruction or excision of the transformation zone
936(66). Ablation should not be considered in cases where colposcopy is inadequate,
CIN 2 and/or 3 is recurrent, or endocervical sampling is positive. This
recommendation is based on a meta-analysis showing that CIN 2 progresses to
CIS in 20% of cases and to invasion in 5%. Progression of CIS to invasion is 5%
(71). Surveillance with co-testing at 12 and 24 months is necessary prior to
returning a patient to routine age-appropriate screening (66).
937938FIGURE 16-11 A: Mosaic pattern and punctation. This pattern develops as islands of
dysplastic epithelium proliferate and push the ends of the superficial blood vessels away,
creating a pattern that looks like mosaic tiles. B: Diagram of mosaic pattern.
There are exceptions to this therapeutic recommendation. The first is among
pregnant women, who in the absence of invasive disease, are followed with
cytology and colposcopy, until reevaluation at 6 weeks postpartum. Additionally,
in recognition of the small but real risk for preterm birth, in young women less
than 25 years of age with CIN 2–3, a program of intensive observation with
colposcopy and cytology is performed at 6 and 12 months, and if normal,
followed by co-testing in another year (66).
FIGURE 16-12 Human papillomavirus (HPV)/cervical intraepithelial neoplasia 3 (CIN 3).
Cribriform pattern of HPV at periphery with mosaicism and punctation near the
squamocolumnar junction.
[15] Although CIN 2–3 can be treated with a variety of outpatient
techniques, the preferred treatment is LEEP. This allows pathologic
evaluation to identify occult microinvasive cancer or adenomatous involvement.
In the latter case, margin status has important prognostic implications. The
939persistent and recurrent disease rate post treatment is estimated at 4% to 10%
(72,73).
Ablative therapy using cryotherapy, laser ablation, or any other technique
is not appropriate when there is CIN 2–3 in the endocervix based on colposcopy
and endocervical curettage (ECC), or evidence of microinvasive or invasive
cancer on cytology, colposcopy, ECC, or biopsy.
FIGURE 16-13 Cervical intraepithelial neoplasia grade 3 (CIN 3).
Cervical Adenocarcinoma In Situ
In adenocarcinoma in situ (AIS), the endocervical glandular cells are replaced by
tall columnar cells with nuclear stratification, hyperchromasia, irregularity, and
increased atypical mitotic activity (74). Cellular proliferation results in crowded,
cribriform glands. The normal branching pattern of the endocervical glands is
preserved. About 50% of women with cervical AIS have squamous CIN 2–3, and
AIS lesions represent incidental findings in specimens removed for treatment of
squamous neoplasia. Usually AIS is located near or above the transformation
zone and conventional cervical specimens may not be effective for detecting
glandular disease. Obtaining good endocervical specimens by Cytobrush may
improve the detection of AIS during the screening process.
940FIGURE 16-14 Colposcopic findings of CIN 3: cuffed gland openings and ridge sign.
[16] AIS is a cancer precursor, and the preferred management for women
who have completed childbearing and have a histologic diagnosis of AIS on a
specimen from a diagnostic excisional procedure is hysterectomy (66). A
histologic diagnosis of AIS from a punch biopsy or a cytologic diagnosis of AIS
is insufficient to justify hysterectomy in the absence of a diagnostic excisional
procedure.
Conservative management with conization can be considered for women
desiring future fertility (66). In such a setting, the status of surgical conization
margins and endocervical sampling at the time of surgery are critical. If either is
positive, reexcision is recommended because of the risk of cancer.
The limits of AIS lesions are difficult to establish by colposcopy or pathology
because of frequent extension of disease within the endocervical canal and the
presence of multifocal, “skip lesions” (i.e., lesions that are not contiguous). For
this reason, negative margins on an excisional specimen may not be entirely
reassuring.
There is good evidence that AIS may progress to invasive cancer (75). In a
study of 40 patients with AIS who had cervical conization, 23 of 40 patients
(58%) had coexisting squamous intraepithelial lesions and 2 had invasive
squamous cell carcinoma (76). Of the 22 patients who underwent hysterectomy,
the margins on the cone specimen were positive in 10 patients, and 70% had
residual AIS, including 2 patients with foci of invasive adenocarcinoma. One of
the 12 patients with negative margins had focal residual adenocarcinoma in the
hysterectomy specimen, and 18 women had conization only with negative
margins and no relapse of disease after a medium interval of 3 years. Thus,
positive margins on the conization specimen are significant findings in these
941patients (77). In a more alarming study of 28 patients with AIS, of the 8 patients
with positive margins who underwent repeat conization or hysterectomy, 3 had
residual AIS and 1 patient had invasive adenocarcinoma (78). Of 10 patients with
negative margins who underwent hysterectomy or repeat conization, 4 had
residual AIS. One patient in whom the cone margin could not be evaluated had
invasive adenocarcinoma. Of the 15 patients treated conservatively with repeat
conization of the cervix and close follow-up, 7 (47%) had a recurrent glandular
lesion detected after the conization, including invasive adenocarcinoma in 2
women. A glandular lesion was not suspected in 48% of the patients, based on
Pap test and ECC results obtained before conization of the cervix.
FIGURE 16-15 Colposcopy findings of CIN 3: rag sign and cuffed gland openings.
In all cases post conization for AIS, recommended surveillance requires
reassessment at 6 months using a combination of cytology, colposcopy, HPV
DNA testing, and endocervical sampling for women who do not undergo
hysterectomy.
Treatment Modalities
Cryotherapy
Cryotherapy destroys the surface epithelium of the cervix by crystallizing the
intracellular water, resulting in the eventual destruction of the cell. The
temperature needed for effective destruction must be in the range of −20° to
−30°C. Nitrous oxide (−89°C) and carbon dioxide (−65°C) produce temperatures
below this range and, therefore, are the most commonly used gases for this
procedure.
942The technique believed to be most effective is a freeze-thaw-freeze method in
which an ice ball is achieved 5 mm beyond the edge of the probe. The time
required for this process is related to the pressure of the gas; the higher the
pressure, the faster the ice ball is achieved. Cryotherapy is an effective treatment
for CIN with very acceptable failure rates under certain conditions (79–82). It is a
relatively safe procedure with few complications. Cervical stenosis is rare but can
occur. Posttreatment bleeding is uncommon and is usually related to infection.
Cure rates are related to the grade of the lesion; CIN 3 has a greater chance of
treatment failure (Table 16-5). Townsend showed that cures are related to the size
of the lesion; those covering most of the ectocervix have failure rates as high as
42%, compared with a 7% failure rate for lesions less than 1 cm in diameter (83).
Positive findings on ECC can reduce the cure rate significantly. Endocervical
gland involvement is important because the failure rate in women with gland
involvement was 27%, compared with 9% in those who did not have such
involvement (84).
Cryotherapy is acceptable when the following criteria are met:
1. CIN 1 that has persisted for 24 months, or CIN 2
2. Small lesion
3. Ectocervical location only
4. Negative endocervical sample
5. No endocervical gland involvement on biopsy
Table 16-5 Results of Cryotherapy for Cervical Intraepithelial Neoplasia (CIN)
Compared With Grade of CIN
Loop Electrosurgical Excision
Loop electrosurgical excision is a valuable tool for the diagnosis and treatment of
CIN (75,85–94). It offers the advantage of performing an operation that is
simultaneously diagnostic and therapeutic during one outpatient visit (95–105).
The tissue effect of electricity depends on the concentration of electrons (size
of the wire), the power (watts), and the water content of the tissue. If low power
or a large-diameter wire is used, the effect will be electrocautery, and the thermal
943damage to tissue will be extensive. If the power is high (35 to 55 W) and the wire
loop is small (0.5 mm), the effect will be electrosurgical, and the tissue will have
little thermal damage. The actual cutting is a result of a steam envelope
developing at the interface between the wire loop and the water-laden tissue. This
envelope is pushed through the tissue, and the combination of electron flow and
acoustical events separates the tissue. After the excision, a 5-mm diameter ball
electrode is used, and the power is set at 50 W. The ball is placed near the surface
so that a spark occurs between the ball and the tissue. This process is called
electrofulguration, and it results in some thermal damage that leads to hemostasis.
If too much fulguration occurs, the patient will develop an eschar with more
discharge, and the risk for infection and late bleeding will be higher.
Loop excision should not typically be used before a high-grade
intraepithelial lesion is identified with histopathology. [17] However,
treatment after an HSIL cytology may be appropriate in certain settings and
among populations for whom colposcopic follow-up is not possible.
LEEP may be associated with an increased risk of overall preterm delivery,
preterm delivery after premature rupture of membranes, and low–birth-weight
infants in subsequent pregnancies at greater than 20 weeks’ gestation (106). The
excision of the entire transformation zone along with varying amounts of the
cervical canal, may compromise birth outcomes (92,94). This is particularly true
for young women, who may have large, immature transformation zones with
extensive acetowhite areas. Complications following loop electrosurgical excision
are relatively minor and compare favorably with those following laser ablation
and conization. Intraoperative hemorrhage, postoperative hemorrhage, and
cervical stenosis can occur but at low rates. The SCJ is visible in more than 90%
of patients after this procedure. Effectiveness of LEEP and comparison of LEEP
to other excision procedures are shown in Tables 16-9 and 16-10.
Conization
Conization of the cervix plays an important role in the management of CIN. It can
be accomplished with a scalpel, electrosurgical needle, or laser. Before the
availability of colposcopy, conization was the standard method of evaluating an
abnormal Pap test result. Conization is a diagnostic and therapeutic procedure and
has the advantage over ablative therapies of providing tissue for further evaluation
to rule out invasive cancer and accurately assess surgical margins
(100,101,103,107).
[18] Conization is indicated for diagnosis in women with CIN 3 or AGC-AIS
and may be considered under the following conditions:
1. Limits of the lesion cannot be visualized with colposcopy.
9442. The SCJ is not evaluable at colposcopy.
3. ECC histologic findings are positive for CIN 2 or CIN 3.
4. Substantial lack of correlation between cytology, biopsy, and colposcopy
results.
5. Microinvasion is suspected based on biopsy, colposcopy, or cytology results.
6. The colposcopist is unable to rule out invasive cancer.
Lesions with positive margins are more likely to recur after conization (Table
16-8) (100,101,103). Endocervical gland involvement is predictive of recurrence
(23.6% with gland involvement compared with 11.3% without gland
involvement) (108). When compared with conization, LEEP is the simpler
technique, and short-term results are similar to those obtained with conization or
laser excision (72,109). In a prospective study examining the long-term effects of
LEEP, conization, and laser excision, no difference in recurrence of dysplasia or
in pregnancy outcomes was found (Tables 16-6 and 16-7) (110).
Hysterectomy
[18] Hysterectomy is the treatment of last resort for recurrent high-grade
CIN. In a study of 38 cases of invasive cancer occurring after hysterectomy
among 8,998 women (0.4%), the incidence of significant bleeding, infection, and
other complications, including death, is higher with hysterectomy than with other
means of treating CIN (76). There are some situations in which hysterectomy
remains a valid and appropriate (although not mandatory) method of treatment for
CIN:
1. Microinvasion
2. Histologically confirmed recurrent high-grade CIN
3. Co-occurring gynecologic pathology requiring hysterectomy, such as fibroids,
prolapse, endometriosis, and pelvic inflammatory disease
Table 16-6 Complications of Electrosurgical Excision
945Table 16-7 Unsuspected Invasion in Electrosurgical Excision Specimens
Table 16-8 Grade of Discomfort of Large Loop Excision Versus Laser Conization
Side Effect Loop Excision (n = 98) Laser (n = 101)
Not unpleasant 80 (92%) 32 (32%)
Moderately unpleasant 16 (16%) 50 (50%)
Very unpleasant 2 (2%) 19 (18%)
Operative time 20–50 sec 4–15 min
(mean, 16 sec) (mean, 6.5 min)
946From Gunasekera PC, Phipps JH, Lewis BV. Large loop excision of the transformation
zone (LLETZ) compared to carbon dioxide laser in the treatment of CIN: a superior mode
of treatment. Br J Obstet Gynaecol 1990;97:995–998, with permission.
Table 16-9 Results of Loop Electrosurgical Excision
Author (Ref. No.) Patients Treated Patients Recurred
Prendiville et al. (85)
102
2
Whiteley and Olah (86)
80
4
Bigrigg et al. (87)
1,000
41
Gunasekera et al. (88)
98
7
Luesley et al. (92)
616
27
Murdoch et al. (93)
600
16
Total
2,496 97 (3.9%)
Table 16-10 Recurrence of Cervical Intraepithelial Neoplasia After Cone Biopsy
VAGINAL INTRAEPITHELIAL NEOPLASIA
Vaginal intraepithelial neoplasia (VAIN) often accompanies CIN and shares a
947common etiology (111). Such lesions may be extensions onto the vagina from the
CIN, or they may be satellite lesions occurring mainly in the upper vagina.
Because the vagina does not have a transformation zone with immature epithelial
cells to be infected by HPV, the mechanism of entry for HPV is by way of
microabrasions resulting primarily from insertional sexual activity. As these
abrasions heal with metaplastic squamous cells, the HPV may begin its growth in
a manner similar to that in the cervical transformation zone. VAIN lesions are
asymptomatic. Because they often accompany active HPV infection, the patient
may report vulvar warts or an odoriferous vaginal discharge from vaginal warts.
Diagnosis
Women with an intact cervix should undergo routine cytologic screening. VAIN
is nearly always accompanied by CIN and cytology is likely to be positive when
VAIN is present. The vagina should be carefully inspected by colposcopic
examination at the time of colposcopy for any CIN lesion. Particular attention
should be paid to the upper vagina. Women who have persistent abnormal
cytology without evident cervical pathology and those with abnormal
cytology after treatment of CIN should be examined carefully for VAIN. For
women in whom the cervix was removed for high-grade cervical neoplasia, Pap
testing should be performed at regular intervals (e.g., yearly), depending on the
diagnosis and severity of lesion.
Colposcopic examination and directed biopsy are the mainstays of diagnosis of
VAIN. Typically, the lesions are located along the vaginal ridges, are ovoid in
shape and slightly raised, and often have surface spicules. VAIN 1 lesions usually
are accompanied by a significant amount of koilocytosis, indicating their HPV
origin (Fig. 16-16). VAIN 2 exhibits a thicker acetowhite epithelium, a more
raised external border, and less iodine uptake (Fig. 16-17A). When VAIN 3
occurs, the surface may become papillary, and the vascular patterns of punctation
and mosaic may occur (Fig. 16-17B). Early invasion is typified by vascular
patterns similar to those of the cervix.
948FIGURE 16-16 Human papillomavirus (HPV)/vaginal intraepithelial neoplasia grade 1
(VAIN 1). Note the surface spicules with partial uptake of Lugol’s stain.
Treatment
[19] Patients with VAIN 1/HPV or VAIN 2 do not require treatment and
may be managed with surveillance. These lesions often regress, are multifocal,
and recur quickly when treated with ablative therapy. VAIN 3 lesions are more
likely to be associated with early invasive disease. In a study of 32 patients who
underwent upper vaginectomy for VAIN 3, occult invasive carcinoma was found
in 9 patients (28%) (112). It is recommended in older patients that VAIN 3
lesions located in the dimples of the vaginal cuff be excised to rule out occult
invasive cancer. [19] VAIN 3 lesions that are adequately sampled to rule out
invasive disease can be treated with laser therapy or excisional therapy. The
major advantage of laser vaporization therapy is the ability to control the
depth and width of destruction by direct vision through the colposcope. The
other advantage of laser therapy is the rapid posttreatment healing phase. This
process takes about 3 to 4 weeks, after which time a new epithelium has formed
completely and, in most cases, has a mature glycogen-containing epithelium.
Tissue Interaction
949When the laser beam contacts tissue, its energy is absorbed by the water in the
cells, causing it to boil instantly. The cells explode into a puff of vapor (thus the
term laser vaporization). The protein and mineral content are incinerated by the
heat and leaves a charred appearance at the base of the exposed area. The depth of
laser destruction is a function of the power of the beam (in watts), the area of the
beam (in millimeters squared), and the length of time the laser remains in the
tissue. The beam must be moved uniformly across the tissue surface to prevent
deep destruction. The laser beam vaporizes a central area and leaves a narrow
zone of heat necrosis surrounding the laser crater. The goal of laser vaporization
is to minimize the area of tissue necrosis. This goal is accomplished by using high
wattage (20 W) with medium beam size (1.5 mm) and moving the beam
uniformly but quickly over the surface. The zone of thermal necrosis will be 0.1
mm when the laser is used in this manner. Some lasers have a function called
super pulse, in which the laser beam is electronically switched off and on
thousands of times per second, thereby allowing the tissue to cool between pulses
to create less thermal necrosis.
950951FIGURE 16-17 A: Vaginal intraepithelial neoplasia grade 2 (VAIN 2). B: Vaginal
intraepithelial neoplasia grade 3 (VAIN 3).
Cryosurgery should not be used in the vagina because the depth of injury
cannot be controlled and inadvertent injury to the bladder or rectum may occur.
Superficial fulguration with electrosurgical ball cautery may be used under
colposcopic control to observe the depth of destruction by wiping away the
epithelial tissue as it is ablated. Excision is an excellent method for treatment of
upper vaginal lesions in a small area. Occasionally, total vaginectomy will be
required for a VAIN 3 lesion occupying the entire vagina. It should be
accompanied by a split-thickness skin graft. This aggressive treatment for
widespread vaginal lesions should not be used for VAIN 2.
The malignant potential of VAIN appears to be less than that of CIN. In a
review of 136 cases of CIS of the vagina over a 30-year period, 4 cases (3%)
progressed to invasive vaginal cancer despite the use of various treatment
methods (111).
VULVAR INTRAEPITHELIAL DISEASE
Vulvar Dystrophies
In the past, terms such as leukoplakia, lichen sclerosis et atrophicus, primary
atrophy, sclerotic dermatosis, atrophic and hyperplastic vulvitis, and kraurosis
vulvae were used to denote disorders of epithelial growth and differentiation
(113). In 1966, Jeffcoate suggested that these terms did not refer to separate
disease entities because their macroscopic and microscopic appearances were
variable and interchangeable (114). He assigned the generic term chronic vulvar
dystrophy to the entire group of lesions.
The International Society for the Study of Vulvar Disease (ISSVD)
recommended that the old dystrophy terminology be replaced by a new
classification under the pathologic heading nonneoplastic epithelial disorders of
skin and mucosa. This classification is shown in Table 16-11. In all cases,
diagnosis requires biopsy of suspicious-looking lesions, which are best detected
by careful inspection of the vulva in a bright light aided, if necessary, by a
magnifying glass (115).
The malignant potential of these nonneoplastic epithelial disorders is low, and
lesions with atypia are classified as vulvar intraepithelial neoplasia (VIN).
Patients with lichen sclerosis and concomitant hyperplasia may be at particular
risk (116).
Vulvar Intraepithelial Neoplasia
952As with the vulvar dystrophies, there is confusion regarding the nomenclature for
VIN. Four major terms are used: erythroplasia of Queyrat, Bowen disease,
carcinoma in situ simplex, and Paget disease. In 1976, the ISSVD decreed that
the first three lesions were merely gross variants of the same disease process and
that all of these entities should be included under the umbrella term squamous cell
carcinoma in situ (stage 0) (92). In 1986, the ISSVD recommended the term
vulvar intraepithelial neoplasia (Table 16-11).
Table 16-11 Classification of Epithelial Vulvar Diseases
Nonneoplastic epithelial disorders of the skin and mucosa
Lichen sclerosis (lichen sclerosis et atrophicus)
Squamous hyperplasia (formerly hyperplastic dystrophy)
Other dermatoses
Mixed nonneoplastic and neoplastic epithelial disorders
Intraepithelial neoplasia
Squamous intraepithelial neoplasia
VIN 1
VIN 2
VIN 3 (severe dysplasia or carcinoma in situ)
Nonsquamous intraepithelial neoplasia
Paget disease
Tumors of melanocytes, noninvasive
Invasive tumors
VIN, vulvar intraepithelial neoplasia.
From Committee on Terminology, International Society for the Study of Vulvar
Disease. New nomenclature for vulvar disease. Int J Gynecol Pathol 1989;8:83, with
permission.
VIN is graded as 1 (mild), 2 (moderate), or 3 (severe or CIS) on the basis of
cellular immaturity, nuclear abnormalities, maturation disturbance, and mitotic
activity. In VIN 1, immature cells, cellular disorganization, and mitotic activity
occur predominantly in the lower one-third of the epithelium, whereas in VIN 3,
immature cells with scanty cytoplasm and severe chromatinic alterations occupy
most of the epithelium (Fig. 16-18). Dyskeratotic cells and mitotic figures occur
in the superficial layer. The appearance of VIN 2 is intermediate between VIN 1
and VIN 3. Additional cytopathic changes of HPV infection, such as perinuclear
953halos with displacement of the nuclei by the intracytoplasmic viral protein,
thickened cell borders, binucleation, and multinucleation, are common in the
superficial layers of VIN, especially in VIN 1 and VIN 2. These viral changes are
not definitive evidence of neoplasia but are indicative of viral exposure (117).
Most vulvar condylomas are associated with HPV-6 and -11, whereas HPV-16 is
detected in more than 80% of VIN cases by molecular techniques.
[20] VIN 3 is a neoplastic precursor and can be unifocal or multifocal.
Typically, multifocal VIN 3 presents with small hyperpigmented lesions on the
labia majora (Fig. 16-19). Some cases of VIN 3 are more confluent, extending to
the posterior fourchette and involving the perineal tissues. The term bowenoid
papulosis (bowenoid dysplasia) was used to describe multifocal VIN lesions
ranging from grade 1 to 3. Clinically, patients with bowenoid papulosis present
with multiple small pigmented papules (40% of cases) that are usually less than 5
mm in diameter. Most women with these lesions are in their 20s, and some are
pregnant. After childbirth, the lesions may regress spontaneously. The term
bowenoid papulosis is no longer recommended by the ISSVD.
The American College of Obstetrics and Gynecology published a committee
opinion on the management of VIN (118). The report indicates that VIN 1 is no
longer considered a precancerous lesion. It is most often an HPV lesion or
may be overcalled, and does not require treatment. VIN 2 with p16 positive
should be treated in the same manner as VIN 3. VIN 2 lesions with negative
p16 can be observed.
VIN Treatment
The treatment of VIN 3 varies from wide excision to the performance of a
superficial or “skinning” vulvectomy (119–122). Although the treatment
originally recommended for CIS of the vulva was wide excision, fears that the
disease is preinvasive led to the widespread use of superficial vulvectomy (121).
Because progression is relatively uncommon, typically occurring in 5% to 10% of
cases, extensive surgery is not warranted (119). This is particularly important
because many VIN 3 lesions are found in premenopausal women.
The therapeutic alternatives for VIN 3 are simple excision, laser ablation,
and superficial vulvectomy with or without split-thickness skin grafting.
Excision of small foci of disease produces excellent results and has the advantage
of providing a histopathologic specimen. Although multifocal or extensive lesions
may be difficult to treat by this approach, it offers the potential for the most
cosmetic result. Repeat excision is often necessary but can usually be
accomplished without vulvectomy (120,122).
954FIGURE 16-18 Carcinoma in situ of the vulva (vulvar intraepithelial neoplasia grade 3,
VIN 3).
The carbon dioxide laser can be used for multifocal lesions but is unnecessary
for unifocal disease. The disadvantages are that it can be painful and costly and
does not provide a histopathologic specimen (123).
Superficial vulvectomy is appropriate to treat extensive and recurrent VIN 3
(122). The goal of the surgery is to extirpate all of the disease while preserving as
much of the normal vulvar anatomy as possible. The anterior vulva and the
clitoris should be preserved if possible. In some patients, the disease extends up
the anus, which must be resected. An effort should be made to close the vulvar
defect primarily, reserving the use of skin grafts for instances in which the vulvar
defect cannot be closed because the resection is so extensive. Split-thickness skin
grafts can be harvested from the thighs or buttocks, but the latter is more easily
concealed (124).
Paget Disease of the Vulva
Extramammary Paget disease of the vulva (AIS) was described 27 years after the
description by Sir James Paget of the mammary lesion that now bears his name
955(125). Some patients with vulvar Paget disease have an underlying
adenocarcinoma, although the precise frequency is difficult to ascertain.
FIGURE 16-19 Vulvar carcinoma in situ: carcinoma in situ (VIN 3) extending into the
hair follicle.
956FIGURE 16-20 Paget disease of the vulva. The epidermis is permeated by abnormal cells
with vacuolated cytoplasm and atypical nuclei. This heavy concentration of abnormal cells
in the parabasal layers is typical of Paget disease.
Histology
Most cases of vulvar Paget disease are intraepithelial. Because these lesions
demonstrate apocrine differentiation, the malignant cells are believed to arise
from undifferentiated basal cells, which convert into an appendage type of cell
during carcinogenesis (Fig. 16-20). The “transformed cells” spread
957intraepithelially throughout the squamous epithelium and may extend into the
appendages. In most patients with an underlying invasive carcinoma of the
apocrine sweat gland, Bartholin gland, or anorectum, the malignant cells are
believed to migrate through the dermal ductal structures and reach the epidermis.
In such cases, metastasis to the regional lymph nodes and other sites can occur.
Paget disease must be distinguished from superficial spreading melanoma. All
sections should be studied thoroughly using differential staining, particularly
periodic acid–Schiff (PAS) and mucicarmine stains. Mucicarmine has routinely
positive results in the cells of Paget disease and negative results in melanotic
lesion.
Clinical Features
Paget disease of the vulva predominantly affects postmenopausal white women,
and the presenting symptoms are usually pruritus and vulvar soreness. The lesion
has an eczematoid appearance macroscopically and usually begins on the hairbearing portions of the vulva (Fig. 16-21). It may extend to involve the mons
pubis, thighs, and buttocks. Extension to the mucosa of the rectum, vagina, or
urinary tract is described (126). The more extensive lesions are usually raised and
velvety in appearance.
A second synchronous or metachronous primary neoplasm is associated with
extramammary Paget disease in about 4% of patients, which is much less
common than previously believed (127). Associated carcinomas were reported in
the cervix, colon, bladder, gallbladder, and breast. When the anal mucosa is
involved, there usually is an underlying rectal adenocarcinoma (116).
Treatment
Unlike squamous cell VIN 3, in which the histologic extent of disease correlates closely
with the macroscopic lesion, Paget disease usually extends well beyond the gross lesion
(128). This extension results in positive surgical margins and frequent local recurrence
unless a wide local excision is performed (129). Underlying adenocarcinomas are
apparent clinically, but this finding does not occur invariably; therefore, the underlying
dermis should be removed for adequate histologic evaluation. For this reason, laser
therapy is unsatisfactory in treating primary Paget disease. If underlying invasive
carcinoma is present, it should be treated in the same manner as a squamous vulvar
cancer. This treatment usually requires radical vulvectomy and at least an ipsilateral
inguinal–femoral lymphadenectomy.
958FIGURE 16-21 Paget disease of the labium majus.
Recurrent lesions are almost always in situ, although there was at least one
report of an underlying adenocarcinoma in recurrent Paget disease (127). It is
reasonable to treat recurrent lesions with surgical excision.
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