Anesthesia procedure and instrument kit
Some patients may benefit from the application of topical lidocaine 4% cream (L.M.X.4) prior to the injection of a local anesthetic for tissue biopsy. Ideally, topical lidocaine should be placed on the vulva and covered with a dressing such as Tegaderm or cellophane up to 30 minutes before the anticipated biopsy procedure. The anesthetic effect generally lasts for about 60 minutes. Many patients report stinging for several seconds upon application. Due to clinic time restrictions, we tend to reserve this method for a limited subset of patients. If planning a return visit for a biopsy, the patient can place the topical anesthetic herself.
For the anesthetic injection, we recommend lidocaine 1% or 2% with epinephrine in all areas of the vulva except for the glans clitoris. For a punch biopsy, we draw up 1 to 3 mL in a 3-mL syringe and inject with a 21- to 30-gauge needle, using a lower gauge for thicker tissue. We have not found buffering the anesthetic with sodium bicarbonate to be of particular use. For the glans clitoris, lidocaine without epinephrine should be utilized.
Equipment. Depending on your office setting, having a premade instrument kit may be preferred to peel-pack equipment. We prefer a premade tray that contains sterile gauze, a hemostat, iris scissors, a needle driver, a scalpel handle, and Adson forceps (FIGURE 1).
Types of biopsy procedures
Punch biopsy. We recommend a 4-mm Keyes biopsy punch. As mentioned, we use a biopsy kit to facilitate the procedure. After the tissue is properly anesthetized and prepped, we test the area via gentle touch to the skin with the hemostat or Adson forceps. To perform the punch biopsy, gentle, consistent pressure in a clockwise-counterclockwise fashion yields the best results. The goal is to obtain a 5-mm depth for hair-bearing skin and a 3-mm depth for all other tissue.2 The tissue should then be excised at the base with scissors, taking care not to crush the specimen with forceps.
Punch biopsy permits sampling of the epidermis, dermis, and subcutaneous tissue. Hemostasis is maintained with either silver nitrate, Monsel’s solution (ferric sulfate), or a dissolvable suture such as 4-0 Monocryl (poliglecaprone 25) or Vicryl Rapide (polyglactin 910).
Stitch biopsy. We find the stitch biopsy to be very useful given the architecture of the vulva. A modification of the shave biopsy, the stitch biopsy is depicted in FIGURE 2. A 3-0 or 4-0 dissolvable suture is placed through the intended area of biopsy. Iris scissors are used to undermine the tissue while the suture is held on tension. The goal is to remove the suture with the specimen. Separate sutures are used for hemostasis. The stitch does not cause the crushing artifacts on prepared specimens. Depending on the proceduralist’s comfort, a relatively large sample can be obtained in this fashion. If the suture held on tension is inadvertently cut, a second pass can be made with suture; alternatively, care can be used to remove remaining tissue with forceps and scissors, again avoiding crush injury to the tissue.
Excisional biopsy. Often, a larger area or margins are desired. We find that with adequate preparation, patients tolerate excisions in the office quite well. The planned area for excision can be marked with ink to ensure margins. Adequate anesthesia is instilled. A No. 15 blade scalpel is often the best size used to excise vulvar tissue in an elliptical fashion. Depending on depth of incision, the tissue may need to be approximated in layers for cosmesis and healing.
When planning an excisional biopsy, place a stitch on the excised tissue to mark orientation or pin out the entire specimen to a foam board to help your pathologist interpret tissue orientation.
The box "Vulvar biopsy established the diagnosis" at the end of this discussion provides 6 case examples of vulvar lesions and the respective diagnoses confirmed by biopsy.
Continue to: Preparing tissue for the pathologist...