Keywords
anal colposcopy - high-resolution anoscopy - anal high-grade squamous intraepithelial
lesion - anal condyloma
Introduction
The prevalence of anal squamous cell carcinoma (ASCC) has continued to rise over the
decades.[1]
The high-risk group for ASCC includes patients with persistent HPV infection, immunosuppressive
disorders, men who have sex with men (MSM), and women with a history of cervical or
vaginal cancer.[2]
[3]
[4]
[5]
Anal low-grade squamous intraepithelial lesion (LSIL) is not considered a direct precursor
of ASCC and can regress spontaneously or progress to anal high-grade squamous intraepithelial
lesion (HSIL).[6]
[7] In contrast, HSIL has less propensity to regress, particularly when containing high-risk
oncogenic types, and is considered premalignant.[7] Retrospective studies clearly show this evolution.[8]
[9] Berry et al.[7] followed 138 HIV-positive men for 15 years and found that 27 patients developed
ASCC at previous biopsy sites that had exhibited HSIL. In the high-risk group, this
progression was estimated at 1 in 377 cases per year.[10]
Anal colposcopy is the gold standard for identifying anal lesions for biopsy.[11]
[12]
Identifying these lesions on high-resolution anoscopy depends on the understanding
and recognition of four main features: color tone and intensity of the acetowhite,
margins and surface contour of the acetowhite areas, vascular features, and iodine
staining pattern.
Anal LSILs are associated with less dense and less extensive acetowhite areas compared
with HSILs, which are chalky-white, greyish-white in appearance and are thicker, dense,
more extensive and have more complex lumen.[13]
When neoplasia develops as a result of HPV infection, the capillary system may be
trapped into the dysplastic epithelium and a thin epithelium layer can cover these
vessels. This forms the basis of punctate and mosaic blood vessel patterns. ([Figs. 1 A] and [B]).
Fig. 1 Lesion: A. Punctation; B. Mosaic, C. Verrucous; D. Ulcerated; E. Atypical vessels.
Verrucous lesions ([Fig. 1 C]) have a characteristic aspect, exhibiting a papilla or arborescent, spiral, stacked
vascular surface. These lesions can evolve to ulcers or atypical vessels that are
associated with HSIL ([Figs. 1 D] and [E]).
Based on the premise that anal colposcopy is the gold standard for diagnosing subclinical
lesions resulting from HPV, together with the steady rise in ASCC incidence, the high
rates of neoplasia recurrence and the success of follow-up programs in reducing cervical
cancer, the present study compared changes on anal colposcopy against histology findings,
given that these changes are used to guide the selection of lesions for biopsy, thereby
helping to reduce the incidence of ASCC.
The objective of the present study was to compare morphological changes on anal colposcopy
against histology to diagnose anal high-grade squamous intraepithelial neoplasia in
patients without clinical lesions.
Casuistic
Casuistic
A retrospective assessment data of HIV-negative and HIV-positive patients undergoing
outpatient follow-up after eradication of clinical HPV-associated anal lesions was
performed. Patients treated between January 2014 and July 2017 were included.
Sample Characteristics
The sample comprised 54 patients presenting acetowhite lesions on follow-up anal colposcopy
30 days after management of condyloma acuminata of the anal margin and/or canal.
Inclusion Criteria
The sample included patients > 18 years old exhibiting biopsied acetowhite lesions
on follow-up anal coloscopy.
Methods
The present study was approved by the Research Ethics Committee of the Instituto de
Infectologia Emílio Ribas (IIER) under the opinion number 2,845,945, and written informed
consent was obtained from all subjects.
Anal Coloscopy
A conventional colposcope (Medpej 7000, binocular with 7–25 X optic lenses) was employed
for the tests. The test method entailed the following standard procedure: application
of 3% acetic acid to the anal margin and canal; examination of the region after 2 minutes
at different magnifications (5x to 40x) for acetowhite areas. Acetowhite lesions were
biopsied, and the specimens were sent to the Pathologic Anatomy Laboratory. The specimens
were classified as anal HSIL, LSIL or normal.
Findings on Anal Coloscopy
Findings were classified as negative, in the absence of changes, or as positive, in
the presence of acetowhite areas and/or of areas not stained with iodine solution.
These lesions were then classified according to their morphology into punctation,
verrucous, mosaic, ulcerated or hypervascularized.
Statistical Analysis
The data were analyzed using SPSS for Windows version 13.0 (SPSS Inc., Chicago, IL,
USA). The results were analyzed using the nonparametric Mann-Whitney test, the Fisher
exact test, and the chi-squared parametric test. A 95% confidence interval (CI) was
used and a level of significance < 5% was adopted for all statistical tests.
Results
Gender
The results of the statistical analysis using the Fisher exact test revealed that
both the HIV- positive and -negative sample was predominantly male. ([Table 1]).
Table 1
Distribution of 54 patients submitted to anal coloscopy, by gender and HIV-positivity
|
HIV infection
|
Negative
|
Positive
|
Total
|
|
Female
|
0 (0.0%)
|
4 (100%)
|
4 (100%)
|
|
Male
|
10 (20%)
|
40 (80%)
|
50 (100%)
|
|
Total
|
10 (18.5%)
|
44 (81.5%)
|
54 (100%)
|
Instituto de Infectologia Emílio Ribas, São Paulo, 2020.
Age
Statistical analysis using the Mann-Whitney test showed that HIV-positive patients
were older than HIV-negative patients (p = 0.005).
Morphological Findings of Acetowhite Lesions Disclosed by Anal Colposcopy
Histological Results of Acetowhite Lesions Disclosed by Anal Colposcopy
Characteristics of the groups: ([Table 2]).
Table 2
Distribution of results according to morphological features of acetowhite lesions
disclosed on anal colposcopy and respective histology results
|
Morphology of acetowhite lesions
|
Histology
|
|
Normal
|
Anal LSIL
|
Anal HSIL
|
Total
|
|
Punctation
|
8 (25.8%)
|
22 (71%)
|
1 (3.2%)
|
31 (100%)
|
|
Verrucous
|
4 (23.5%)
|
10 (58.8%)
|
3 (17.7%)
|
17 (100%)
|
|
Mosaic
|
2 (50%)
|
2 (50%)
|
0
|
4 (100%)
|
|
Ulcerated
|
0
|
0
|
1 (100%)
|
1 (100%)
|
|
Atypical Vessels
|
1 (100%)
|
0
|
0
|
1 (100%)
|
Abbreviations: LSIL, low-grade squamous intraepithelial lesion; HSIL, high-grade squamous
intraepithelial lesion.
Chi-squared = 0.167.
Instituto de Infectologia Emílio Ribas, São Paulo, 2020.
No statistical significance was detected, i.e., no morphological type had higher prevalence
of high grade.
Punctation Acetowhite Lesion
This lesion group contained 31 (57.5%) patients, comprising 1 woman and 30 men. The
age of the patients ranged from 18 to 63 years old, with a mean of 40.5 years old.
Six patients were HIV-negative and 25 were HIV-positive.
Verrucous Acetowhite Lesion
This lesion group contained 17 (31.5%) patients, comprising 2 women and 15 men. The
age of the patients ranged from 23 to 63 years old, with a mean of 43 years old. Four
patients were HIV-negative and 13 were HIV-positive.
Mosaic Acetowhite Lesion
This lesion group contained 4 (7.4%) patients, comprising 1 woman and 3 men. The age
of the patients ranged from 30 to 56 years old, with a mean of 43 years old. All patients
in this group were HIV-positive.
Ulcerated Acetowhite Lesion
This group consisted of 1 (1.8%) 51-year-old male patient who was HIV-positive.
Atypical Vessel Acetowhite Lesion
This group consisted of 1 (1.8%) 50-year-old male patient who was HIV-positive ([Table 3]).
Table 3
Acetowhite lesions disclosed on anal colposcopy according to morphological features
and respective histology results for HSIL (%) and 95% confidence interval
|
Morphology of acetowhite lesions
|
n
|
%
|
95%CI
|
|
LB
|
UB
|
|
Verrucous
|
17
|
17.6
|
0.0
|
40.4
|
|
Punctation
|
31
|
3.2
|
0.0
|
10.7
|
Abbreviations: CI, confidence interval; LB, lower bound; UB, upper bound.
Verrucous lesion: proportionally greater rate of HSIL (17.6%), ranging from zero to
40%; - Punctation lesion: rate of HSIL 3.2%, ranging from 0 to 10.7%; Fisher's exact
test (p = 1.0), non-significant.
Instituto de Infectologia Emílio Ribas, São Paulo, 2020.
CD4 Lymphocyte Count
Results of the Fisher exact test (=1) revealed no association between the presence
of HSIL and counts above or below 500/µl in HIV+ patients ([Table 4]).
Table 4
Distribution of 44 HIV-positive patients submitted to anal coloscopy with biopsy of
acetowhite lesions, according to CD4 lymphocyte count above and below 500/µL and presence
of HSIL
|
Histology
|
|
Non-high grade
|
High-grade
|
Total
|
|
CD4 T cell count
|
(Normal + LSIL)
|
HSIL
|
|
|
≤ 500/µl
|
19
|
2
|
21
|
|
> 500/µl
|
21
|
2
|
23
|
|
Total
|
40
|
4
|
44
|
Abbreviations: HSIL, high-grade squamous intraepithelial lesion; LSIL, low-grade squamous
intraepithelial lesion.
Fisher exact test (p = 1.0), nonsignificant, thus confirming CD4 lymphocyte T cell count was not a determinant
factor in the development of HSIL.
Instituto de Infectologia Emílio Ribas, São Paulo, 2020.
Discussion
The present study sample of HIV-positive individuals contained more men than women.
The study results can be explained by the fact that HPV-associated anal lesions can
be more common in men who have sex with men (MSM) and who are also HIV-positive, as
outlined previously.
The HIV-positive group represented 81.5% of the population assessed. The high rate
of HIV-positive patients may be due to the fact that the IIER is a referral service
for AIDS.
Regarding age, the mean age of the individuals was 39.4 years old, with a wide range
between minimum and maximum, findings which are consistent with the literature, showing
high rates of HPV-associated anal lesions across all ages, from 18 to 50 years old.[14]
The HIV-positive patients were older than their HIV-negative counterparts. Studies
have shown that immunosuppression due to HIV tends to perpetuate infection by HPV,
increasing the risk of lesions caused by the virus with age.[15]
[16]
Anal colposcopy is a simple, noninvasive exam that can be used in high-risk patients
for diagnosing ASCC. A recent study by Palefsky et al.[17] reported a large series of patients involving 571 cases. A total of 835 lesions
were described, biopsied and correlated with histology. Four out of the 5 categories
(contour, surface, vascular patterns, and Lugol staining) clearly distinguished HSIL
from LSIL.[18] A study by Jay et al.[19] involving 152 cases and 385 biopsies also found similarities in the colposcopic
appearance of anal lesions compared with cervical lesions and in correlation with
their expected dysplastic grade.
In the present study, acetowhite lesions were classified according to their predominant
morphology into punctation, verrucous, mosaic, ulcerated or atypical vessels.
The examinations revealed 31 (57.5%) punctation, 17 (31.5%) verrucous, 4 (7.4%) mosaic,
1 (1.8%) ulcerated, and 1 (1.8%) atypical vessel lesion. The high incidence of verrucous
lesions (31.5%) might be attributed to the fact that, unlike most studies in which
anal colposcopy of the anal canal alone is performed, the present study also assessed
the anal margin, the perineum and the coccyx region, sites where verrucous lesions
are more prevalent.[20] In addition, the predominant morphology of the lesion was also taken into account
when this was mixed (e.g., verrucous + punctation and/or mosaic) and verrucous lesions
are more visible and overlay flat lesions (punctation and mosaic).
On histology, lesions were normal in 15 (27.7%) cases, LSIL in 34 (63.1%), and HSIL
in 5 (9.2%). This result was congruent with the study objective of biopsying the areas
with abnormal colposcopic appearance, irrespective of whether lesions were suggestive
of HSIL or otherwise.
Detection of a higher rate of HSIL in punctation (3.1%) and mosaic (no cases) lesions
was expected. However, the results revealed that verrucous lesions, classically correlated
with LSIL, exhibited the highest rate of HSIL (17.7%). These results are noteworthy
in that they contradict the literature, particularly regarding evidence related to
the cervix. In the present analysis, punctation and mosaic lesions were not classified
into fine punctation/mosaic, normally associated with low-grade lesions, or into punctation/coarse
mosaic, typically associated with high-grade lesions. Possibly, most of the punctation
lesions and all mosaic lesions biopsied were fine changes.
This subclassification was not done because the anatomical characteristics of the
anal canal render detailed visualization of lesions difficult. This does not rule
out the possibility of more precise classification of subclinical lesions during anal
coloscopy but highlights the need for the appropriate equipment and a high skill level
of the colposcopist.[18]
The current findings corroborate those in the literature showing that ∼between 10
and 14% of lesions with LSIL appearance on anal colposcopy have HSIL histology,[18] where this differentiation can be aided by applying Lugol staining.
High-grade squamous intraepithelial lesions are more common among individuals in high-risk
groups. In the present study, HIV-positive patients had higher HSIL rates, although
this difference did not reach statistical significance. Likewise, no statistical difference
was found for CD4 lymphocytes T cell count above or below 500/µl, confirming that
immunity was not a determinant.
Experience administering colposcopy is an important factor, but even highly skilled
colposcopists can take biopsy samples of lesions suggestive of HSIL that are subsequently
not confirmed histologically. This indicates that a deeper understanding of the features
of subclinical lesions on anal colposcopy could improve the likelihood of biopsying
higher-grade lesions.
Ideally, lesions should be treated while still in their early stages and before progressing
to high-grade clinical lesions. The detection of a higher rate of normal and LSIL
lesions associated with the absence of ASCC in the present cohort shows this objective
is being achieved.
Conclusion
The present study found no specific morphological pattern suggestive of HSIL.
