Vulvar Biopsy

Background

Vulvar biopsy is performed to diagnose lesions of the vulvar epithelium. For small lesions, vulvar biopsy may excise and treat the entire lesion. The procedure can be performed easily, safely, and comfortably in the office setting.

Patient complaints regarding vulvar lesions and skin changes may often be diagnosed through history and physical examination, as well as microscopic examination, culture, or polymerase chain reaction testing. ^[1] These diagnoses include contact dermatitis, candidal vulvitis, and herpes simplex virus infections. However, these methods are insufficient for adequately assessing many other problems. In these instances, histologic diagnosis is required, and office vulvar biopsy is performed. For example, histologic evaluation should be performed on lesions that may be squamous cell dystrophies, lichen sclerosus, melanoma, or invasive cancer of the vulva. Vulvar lesions (see the image below) that can be diagnosed by vulvar biopsy include molluscum contagiosum, lichen sclerosus, vulvar intraepithelial neoplasia, condyloma, and vulvar carcinoma.

Vulvar biopsy is one of the more common gynecological office procedures. However, scant information is available in the literature regarding technique. In this topic, the limited published data are augmented with descriptions of usual clinical practice and the author's experience as necessary.

Indications

Indications for vulvar biopsy include the following:

• Visible lesion for which definitive diagnosis cannot be made on clinical grounds

• Possible malignancy

• Visible lesion with presumed clinical diagnosis that is not responding to usual therapy

• Lesions with atypical vascular patterns

• Benign-appearing lesions requiring definitive diagnosis (eg, acrochordon)

• White lesions failing empiric therapy

Contraindications

No absolute contraindications exist for vulvar biopsy. Relative contraindications include the following ^[2] :

• Infected site (which in some cases may be a reason for biopsy)

• Coagulopathy

• Allergy to local anesthetic

Technical considerations

The vulva is the external genitalia of the human female. It includes the structures encompassed from the pubis to the perineal body: the labia majora, labia minora, clitoris, hymen, vestibule, urethral opening, greater vestibular or Bartholin glands, minor vestibular glands, and paraurethral glands. When performing the biopsy, the main consideration is that vulvar dermis is similar to other skin in terms of pain and healing. The proximity of the rectum and urethra should be taken into account when possible in selecting the biopsy sites.

Patient education and consent

Patient should be consented and counseled on benefits and risks of procedure. The risks include bleeding, infection, scarring, inadequate sample possibly requiring another biopsy procedure, or allergic reaction.

For punch biopsy sites, the patient may take sitz baths afterwards. Soaking is particularly important after bowel movements if the biopsy site is potentially contaminated with stool. The biopsy site should be kept clean and dry. If bleeding occurs, it can generally be stopped by direct pressure from the patient.

Showers are permitted for sutured wounds 24 hours after biopsy, but hot tub baths should be avoided until healing is completed. It will generally take approximately 5 days for healing by secondary intention. The area should be washed once or twice daily, although this is optional for sutured wounds. ^[2]

Equipment

The following instruments are used for vulvar biopsy:

• Iodine or chlorhexidine

• Sterile gauze

• 1- or 3-mL syringes for local anesthesia

• 19- to 22-gauge needle for drawing lidocaine solution

• 30-gauge needle or other smaller-gauge needle for injection into skin

• 1% or 2% lidocaine, with or without epinephrine

• Keyes punch biopsy or scalpel

• Forceps

• Silver nitrate stick or suture (4-0 monocryl)

• 10% formalin specimen bottle

Patient preparation

Vulvar biopsies may be performed in the office with local anesthesia, a Keyes punch biopsy or shave biopsy with a scalpel, and hemostatic agent. Some providers apply topical anesthetic prior to injecting a standard local anesthetic.

Using a large needle, draw 1-3 mL of 1-2% local anesthetic, such as lidocaine. The actual injection should be performed with the smallest needle possible (eg, 27- or 30-gauge) to minimize pain, although the injection will take slightly longer than when using a larger needle. In a small questionnaire study examining pain associated with biopsy procedures, it was shown that the injection was perceived by the majority of patients as the most painful part of the procedure. ^[3]  

When anesthetizing the area, insert the needle and withdraw the plunger to decrease the chance that injection occurs into a vessel. Inject slowly at the base of and underneath the lesion, injecting enough to create a wheal. If possible, only penetrate the skin once. See the image below.

If a larger area needs anesthesia, the needle may be moved gently while being inserted to anesthetize a larger area without having to withdraw the needle and reinserting it into the skin, which may cause more discomfort to the patient.

The wheal should be larger than the biopsy instrument that will be used. Adequate anesthesia for the procedure should be present in 1-2 minutes. Test for appropriate anesthesia using forceps prior to making any incision. As in most clinical situations, biopsy is performed shortly after injection.

Most providers use plain lidocaine, which gives adequate relief and has less side effects. If a mixture with epinephrine is used, it takes approximately 5 minutes for the vasoconstrictive property of epinephrine to take effect. Side effects of lidocaine with epinephrine are metallic taste, increased heart rate, tinnitus, and lightheadedness.

The health care provider may use any common topical antiseptic, such as iodine or chlorhexidine, to prepare the skin after confirming that the patient has no known patient allergies to these antiseptics. See the image below.

Complications

Possible complications of vulvar biopsy include the following:

• Bleeding

• Infection

• Scarring

• Allergic reactions

• Inadequate sample

Approach considerations

The provider performing the biopsy and any assistants should take personal protection precautions and wear gloves and eye equipment. A punch or shave biopsy does not require a mask or sterile gown. Sterile gloves are typically worn. A mask is recommended for providers who are carriers of Staphylococcus or Streptococcus species. ^[2]

Choice of biopsy site

Suspected inflammatory diseases, neoplasias, ulcers, and pigmented lesions should be sampled using punch biopsy that includes the edge of the lesions. For large lesions or lesions where different areas do not appear to be similar, multiple biopsies may be necessary.

Although the biopsy site should be chosen to maximize the chance of getting an appropriate diagnosis, if possible, one should avoid taking the biopsy from the clitoris, labia minora, and urethra because these areas are particularly sensitive. Infection risk is likely decreased and aftercare simplified if the biopsy is not taken near the rectum.

Choice of instrument

The biopsy may be performed using a Keyes punch biopsy or scalpel or scissors. Choice of instrument is generally determined by provider preference and instrument availability. We generally use a punch biopsy for flat or slightly raised lesions, and scalpel or scissors for raised or pedunculated lesions.

The Keyes punch biopsy is routinely used by many providers and is particularly useful when the depth of the lesion is of importance. The Keyes punch is a pen-sized instrument with a sharp, circular cutting edge that is used to cut tissue in a twisting motion. See the image below.

Punch biopsy is useful if the lesion is small enough for complete excision by the biopsy tip. Punch biopsies are available in sizes from 2 mm to 10 mm. A 3-mm punch biopsy is generally thought to be the smallest size that will provide an adequate sample of tissue for pathologic analysis. Punch biopsies may heal without suturing; however, if hemostasis cannot be achieved within a few minutes, sutures may be considered for hemostasis. Postprocedural discomfort secondary to the location of the sutures and the patient’s likelihood of keloid formation should be considered.

In general, the smallest punch biopsy that will adequately sample the lesion should be used. Typically, 4- or 5-mm punch biopsies are used because these sizes generally balance obtaining an adequate specimen with minimal patient discomfort; in addition, they seldom require suturing. Larger lesions needing excisional biopsy with scalpel are generally managed as described below. A larger lesion that is round in shape could be excised using a punch biopsy of larger size that completely circumscribes the lesion. For very large lesions, multiple 4- to 5-mm biopsies may give better sampling and healing than fewer larger biopsies.

Keyes punch biopsy

After adequate local anesthesia, determine the direction of skin tension lines. Using the operator’s nondominant hand, hold the skin taut for stabilization perpendicular to the tension lines.

Place the Keyes punch against the lesion at the chosen biopsy site. Place the punch biopsy firmly against the skin and rotate with a constant firm pressure clockwise and then counterclockwise (if necessary) for penetration through the skin. Avoid a back-and-forth twisting motion or stopping the biopsy midprocedure to check the depth of the biopsy, which may result in a shredded tissue sample with rough edges. See the image below.

Generally there is a change in resistance of the Keyes punch on the skin once the biopsy has reached the subcutaneous fat. At this time, the Keyes punch may be removed and the operator may apply pressure using two fingers to elevate the circular tissue to assist in grasping it with forceps. See the image below.

Using the forceps, further elevate the core of skin and subcutaneous tissue and cut the base of the biopsied tissue with curved iris scissors. Place the excised specimen with the epithelial surface facing upwards on a square piece of filter paper or nonstick pad. ^{[2, 4]}

Shave biopsy

A shave biopsy may be performed using a scalpel or scissors. Injecting the anesthetic underneath the lesion also helps to elevate the lesion.

When using the scalpel, one can use forceps to elevate the lesion and then, using a 15-blade, remove the lesion using a single sweeping stroke (not repeated back-and-forth sawing strokes). The depth of the lesion can be controlled by the angle of the blade.

Curved scissors may also be used to remove a lesion. Use forceps or toothed pick-ups to elevate the lesion. Using the scissors with the curved tips pointed up, excise the lesion. Curved scissors are beneficial for lesions that may need more depth removal or for lesions such as skin tags. ^[2] See the image below.

Fixation

Once an adequate sample has been excised, the specimen should be placed carefully in a fixative solution, such as 10% formalin. Confirm that the sample is in the container after closing the lid. The tissue is now ready to be sent to pathology along with the properly completed pathology forms. If more than one biopsy is being performed, each biopsy should be placed in an appropriately labeled, separate container.

Hemostasis

Bleeding can be stopped in a number of ways. Although hemostasis can be achieved with time and pressure for small sites, typically an active hemostatic agent is used. Shave biopsies may not bleed much and pressure alone may provide hemostasis.

Given that scarring is of limited concern on the vulva, silver nitrate sticks are typically applied. See the image below.

Monsel solution can also be used, but it may be more irritating to surrounding skin. It is important to know that silver nitrate and Monsel solution may also potentially cause increased skin pigmentation. ^[2] When using these hemostatic agents, it is important to dry the area with sterile gauze and then apply the hemostatic agent only to the bleeding area.

A suture can be placed if necessary. If a hemostatic agent has failed, use a needle driver with suture, such as 4-0 monofilament or polygalactin, for reapproximation and hemostasis. Caution should be used when suturing infected tissue.

Dressing

The vulva tends to be a warm and moist environment compared to the rest of the body. Given the location and difficulties in keeping a dressing in place, most vulvar biopsies are not covered with a dressing. When used, the dressing should be chosen with regard to the type of wound closure and location of the biopsy. A spot bandage may be used on the labia majora, for example, but this may be difficult in the presence of pubic hair. In most instances, use of a pad or pantyliner will suffice.

For punch biopsy sites, the patient may take sitz baths. Soaking is particularly important after a bowel movement if the biopsy site is potentially contaminated with stool. The biopsy site should be kept clean and dry. If bleeding occurs, it can generally be stopped by direct pressure from the patient.

Showers are permitted for sutured wounds 24 hours after biopsy, but hot tub baths should be avoided until healing is completed. It will generally take approximately 5 days for healing by secondary intention and the area should be washed once-twice daily. This is optional for sutured wounds. ^[2]