Introduction
The cervix is used as a model for anal
human papilloma virus (HPV)-associated disease based on similar anatomy
and pathophysiology. Both the cervix and anus consist of squamous
epithelium, which abuts columnar epithelium inducing squamous
metaplasia. These areas undergoing squamous metaplasia are most
susceptible to abnormal changes caused by HPV. The same strains of HPV
found in the female genital tract are found in the anal canal of women
and men. They induce the same range of disease in the anus as in the
cervix, vagina, and vulva.
Anal disease is classified with similar
cytology and histology taxonomies as the cervix, although in the anus,
squamous intraepithelial lesions (SIL) is often called anal
intraepithelial neoplasia (AIN) grades I, II, and III. High-grade AIN
(HGAIN) is considered to be the precursor lesion to anal squamous cell
cancer (SCC), and as such, screening procedures used for the cervix
including cytology and colposcopy have been adapted for screening of
anal HPV-associated disease. Sensitivity and specificity of anal
cytology are similar to cervical cytology, and liquid-based cytology has
been shown to improve quality of samples. As a screening test for anal
cancer, anal cytology has been shown to be cost-effective. In the anal
canal, colposcopy is called high-resolution anoscopy (HRA). Colposcopy
techniques and terminology have been validated for anal canal
disease.
Figure 1 View Original Figure 1 View Original
There are several principles of
screening when using anal cytology and HRA. Anal cytology is used for
identification of populations and individuals with HPV-associated
diseases through cytology screening programs. HRA is used for detection
of lesions, histologic diagnosis of disease, and treatment of disease,
specifically HGAIN and prevention of cancer development. It is also used
for early detection of nonsymptomatic cancer.
Before an anal cytology exam or HRA,
instruct the patient to avoid douching, enemas, or insertion of anything
per rectum 24 hours prior to the procedure. Obtain relevant history,
including current anal symptoms such as pruritus, bleeding, and pain.
Determine prior history of anal or perianal condyloma and whether
treatments were surgical or office based. Also determine prior history
of any anal abnormalities such as fissures, fistula, abscesses, or
hemorrhoids requiring intervention. Ask about any prior treatments that
may have caused scarring or other alterations in the normal anal mucosa
such as abscess lancing, fistula repairs, or hemorrhoidectomies. Obtain
informed consent with explanation of the procedures to be performed.
Equipment
Much of the equipment is similar to
that used for cervical examinations. Most gynecology or dysplasia
practices have these supplies without significant additional cost for
performing these procedures. A procedure tray for examination includes
the following:
Figure 2 View Original Figure 2 View Original
Figure 3 View Original Figure 3 View Original
- Cytology liquid medium
(or conventional slide with fixative solution) - Dacron swab
- Anoscope (disposable or
sterilized metal) - 3% acetic Acid
- Nonsterile cotton
swabs - Nonsterile Scopettes
- Nonsterile 4 4
gauze pads - Lugol solution
- K-Y Jelly mixed with
1% to 5% " lidocaine gel
For intra-anal biopsies, the
following additional equipment is needed:
- Monsel solution or silver nitrate
sticks - Formalin
- Baby-Tischler punch
biopsy or endoscopy forceps
For perianal biopsies the
following additional equipment is needed:
- 1% to
5% " lidocaine gel/cream - 1% " lidocaine with epinephrine and sodium bicarbonate (2
mL per 10 cc of lidocaine) - Small pick-up forceps
- 30-gauge needle
- 22-gauge needle
- 1-cc syringe
Colposcope
The following specifications are
recommended for colposcopes intended for HRA:
- Double objective lens
with magnification up to 25 to 40 - Oculars that magnify 10
to 20 - Angled eye pieces, as the
straight-on view is ergonomically difficult for HRA - Side-swing arm to brace
clinician 's arm while holding the anoscope for long
periods - Green filter for
evaluation of vascular changes
Figure 4 View Original Figure 4 View Original
Indications
Populations to screen include the
following:
- HIV-seropositive
individuals - Immune-compromised
individuals (organ transplant recipients, autoimmune
diseases) - HIV-seronegative women
with a history of anal or perianal warts, genital high-grade SIL
(HSIL), or cancer - HIV-seronegative men who
have sex with men with a history of anal or perianal warts or
prior receptive anal intercourse
Contraindications
- There is no
contraindication for cytology screening or HRA, although
patients who have recently undergone anal procedures such as
hemorrhoidectomy, fistula repair, or fulguration of anal warts
should defer examination until healed. - Biopsy should be deferred
in patients with platelets <65,000 or in patients who are
neutropenic or who are on anticoagulant therapies.
The Procedure
Step 1
The anatomy of the anus is
depicted.
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Step 2
The anus is composed of
squamous epithelium. The rectum or colon is columnar epithelium. The
anal canal is mucosa lined, and the anal margin is epidermal. The
proximal end of the anal canal begins at the junction of the ani
muscle and external anal sphincter and extends to the anal verge. It
is 2 to 4 cm in length and is shorter in women compared with that
found in men. The distal end of the anal canal is the dentate line,
which is approximately equivalent to the original squamocolumnar
junction (SCJ) in colposcopic terminology. The dentate line is
considered to be a "fixed " anatomic zone, whereas the
anal transformation zone (AnTZ) is dynamic and undergoing squamous
metaplasia. The AnTZ is the current SCJ. The anal margin begins at
the verge and represents the transition from mucosal to epidermal
epithelium and extends to the perianal skin.
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Step 3
By consensus, perianal skin
is considered to extend approximately 5 cm from the anal margin.
Areas for screening include the SCJ, AnTZ, anal canal, verge,
margin, and perianal skin.
Step 3 View Original Step 3 View Original
Performing Anal Cytology
Step 1
The anal cytology
specimen should be performed first to provide the highest yield
of cells. Gently separate the buttocks. The patient can hold his
or her right cheek to facilitate the view.
- PITFALL: There must be no lubrication
prior to obtaining a cytology sample, as the lubricant
may interfere with the processing and interpretation of
the sample.
Step 1 View Original Step 1 View Original
Step 2
Insert a moistened
Dacron swab approximately 3 to 4 cm into the anus to assure
sampling of cells from the AnTZ. If initial resistance is
encountered, change the position of the swab and reinsert.
Step 2 View Original Step 2 View Original
Step 3
Remove the swab in a
circular motion in order to sample cells from all aspects of the
anal canal. Apply pressure so that the swab bends while slowly
removing it. Count slowly to ten as you remove it. Preserve
quickly on slides or in liquid medium. Fewer cells exfoliate
from the anal canal than the cervix, and it is easier to get
air-dried artifacts.
Step 3 View Original Step 3 View Original
Performing High-Resolution Anoscopy
Step 1
Assist the patient
into one of the following positions: left lateral, lithotomy if
also performing cervical exam (but most women prefer to switch
to left lateral for the HRA), or prone (if overhead colposcope
is available). In the left lateral and prone positions, the
patient should be as close to the bottom edge of the table as
possible to facilitate focusing the colposcope.
Step 2
Be clear and
consistent in describing location of lesions and the position
used. The "anal clock " is different from the
"gynecologic clock. " In the prone position,
posterior is 12:00, while in the lithotomy position, it is 6:00.
When referring patients for follow-up to anal surgeons, it is
helpful to use anatomic descriptors (posterior, anterior, left
or right lateral) in place of or in addition to the
"clock " positions.
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Step 3
Obtain a cytology
specimen if needed (new patients or those referred with abnormal
cytology specimens >3 months old). Lubricate the anal
canal with K-Y Jelly mixed with 1% to
5% " lidocaine. Perform a digital rectal exam,
and palpate for warts, masses, ulcerations, fissures, and focal
areas of discomfort or pain. The presence of hard and fixed
lesions should increase your index of suspicion for cancer,
since these are not the usual presentation of hemorrhoids and
warts.
Step 3 View Original Step 3 View Original
Step 4
Insert the anoscope,
and remove the obturator.
Step 4 View Original Step 4 View Original
Step 5
Insert a cotton swab
wrapped in gauze that has been soaked in acetic acid.
Step 5 View Original Step 5 View Original
Step 6
Remove the anoscope,
leaving the cotton swab " wrapped gauze pad inside. Soak
for 1 to 2 minutes.
Step 6 View Original Step 6 View Original
Step 7
Remove the gauze,
and reinsert the anoscope. Observe through the colposcope while
slowly removing the anoscope until the AnTZ comes into
focus.
Step 7 View Original Step 7 View Original
Step 8
Continue to apply
acetic acid with Scopettes or cotton swabs during the exam.
Using cotton swabs to manipulate the folds, hemorrhoids, or
prolapsing mucosa as well as adjusting the anoscope will help to
view all aspects of the AnTZ. In most cases, the entire AnTZ
should be seen, and the exam will be considered satisfactory.
Continue withdrawing the anoscope until the entire canal has
been observed.
Step 8 View Original Step 8 View Original
Step 9
The AnTZ is seen
here as a thin acetowhite line between the mature squamous and
immature columnar epithelium. Early metaplasia can be seen as
the columnar epithelium begins to coalesce adjacent to the SCJ.
Acetic acid distinguishes anal squamous epithelium from colon
columnar epithelium. Squamous epithelium will generally appear
lighter and pinker in color, while columnar epithelium is darker
and redder.
Step 9 View Original Step 9 View Original
Step 10
Lugol application
may help determine areas of abnormality. Normal glycogenated
squamous epithelium stains dark mahogany. Abnormal lesions lack
glycogen and have a partial stain or no stain. Care must be
taken to differentiate areas that do not pick up Lugol staining,
such as columnar epithelium, scar tissue, and skin. In this
case, a lesion can be seen, which is better delineated than with
acetic acid alone.
- PITFALL: Review allergy to iodine during history taking. If
patient has an allergic reaction to shellfish or has
known allergy to iodine from prior procedures, do
not use during the examination.
Step 10 View Original Step 10 View Original
Step 11
Commonly recognized
cervical lesion characteristics that help distinguish cervical
low-grade SIL (LSIL) and HSIL are also seen in anal lesions and
help guide the clinician in choosing areas for biopsy. A typical
raised low-grade AIN (LGAIN) is shown in part A and a typical
flat high-grade AIN (HGAIN) is shown in part B.
Step 11 View Original Step 11 View Original
Step 12
Biopsies are
directed at areas thought to represent the highest grade of
abnormality. Anal biopsies should be smaller than those
typically taken of the cervix using forceps no larger than 2 to
3 mm. Internal biopsies do not require anesthesia. External
biopsies require injecting a small amount of
1% " lidocaine with epinephrine buffered with sodium bicarbonate (2
cc NaHC03: 10 cc lidocaine), similar to biopsies of the vulva.
The injection can be preceded by numbing medication topically
with lidocaine gel or spray. Monsel solution or silver nitrate is used for hemostasis,
although the pressure of the anal walls will generally stop
bleeding for internal biopsies.
Step 13
Insert closed
forceps through the anoscope while looking through the
colposcope.
- Pearl: Closing the forceps will
prevent unintentional injury.
Step 13 View Original Step 13 View Original
Step 14
Once the forceps is
adjacent to the lesion, open in the direction that allows for
the forceps to grab the tissue. For some lesions, the forceps
will need to be positioned upside down.
- PITFALL: Patients on warfarin (Coumadin) or daily aspirin may
have increased bleeding with biopsy. If the platelet
count is <65,000, approach the biopsy with
caution or postpone until count improves. It is no
longer considered necessary to provide antibiotic
prophylaxis prior to biopsy in patients with history of
endocarditis or otherwise at risk for heart valve
disease.
Step 14 View Original Step 14 View Original
Step 15
To obtain a small
sample, the forceps should not be opened the entire width but
rather should be partially closed before closing and grabbing
the tissue. Monsel solution can be applied to the biopsy site
for hemostasis, although most small biopsy samples will
coagulate spontaneously once the anoscope is removed.
Step 15 View Original Step 15 View Original
Complications
- Bleeding with bowel
movements for several days post biopsy - Infection (rare)
- Problematic bleeding
(rare)
Pediatric Considerations
Since cytology screening is not
usually done until a patient has been sexually active, this procedure is
not routinely done in a pediatric population.
Postprocedure Instructions
Patients should be told to expect
slight bleeding with bowel movements for several days post biopsy. There
may be mild postprocedure pain associated with biopsy of lesions in and
around the anal canal. Rarely, a patient may require medication such as
hydrocodone.
Comfort measures include avoiding
constipation by increasing fiber in the diet during a few days following
biopsy. If the patient requires pain medications, stool softeners may be
necessary, depending on their routine bowel habits. Avoid hot and spicy
foods. Soaking in warm water will facilitate faster healing and relieve
any pain associated with biopsy. Lidocaine 1% to
5% gel/cream can be applied to perianal tissue when biopsies have
been performed.
Follow-up will depend on the results
of the cytology, histology, and the clinical indications for the
referral. See 01412520.
Triage for Anal Cytology and High-Resolution Anoscopy
Figure 5 View Original Figure 5 View Original
Coding Information and Supply Sources
View Large CPT Code Description 2007 AVERAGE 50th Percentile Fee Global Period 46600 Anoscopy $117.00 0 46606 Anoscopy with biopsy, single or multiple $244.00 0 46900 Destruct lesion(s) anus simple, chemical (e.g.,
trichloroacetic acid) $400.00 10 46916 Destruct lesion(s) anus simple, cryosurgery $424.00 10 Use a -22 modifier for use of microscope with
any of above.CPT is a registered trademark of the
American Medical Association.2008 average
50th Percentile Fees are provided courtesy of
2008 MMH-SI 's copyrighted Physicians ' Fees and
Coding Guide.
ICD-9 Codes
View Large 078.11 Anal condyloma 211.4 Benign neoplasms of the anus (AIN I or AIN II) 230.5 HGAIN (AIN III) or carcinoma in situ of the anus 239.2 Anal dysplasia (nonspecific) 154.2 Anal cancer 042 HIV
Supplies for HRA needed in
addition to standard colposcopy supplies include the following:
View Large Item Manufacturer Contact information Anoscopes Cardinal Healthcare 800-477-3800 Endoscopic forceps Fibertech Forceps 714-522-7112 Endoscopic forceps ESCO Medical Instruments 631-689-9153 Infrared coagulator Redfield Corporation http://www.redfieldcorp.com
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