Pigmented vulvar lesions include benign nevi, lentigines, melanosis, seborrheic keratosis, condyloma, and some VINs, especially multifocal VIN-3 (Fig. 14.31). Suspicious pigmented vulvar lesions in particular should warrant biopsy to rule out VIN or malignant melanoma (231). Approximately 10% of white women have a pigmented vulvar lesion; some of these lesions may be malignant (see Chapter 38) or have the potential for progression (VIN) (see Chapter 19). There is an increase in rates of VIN in women younger than age 50, along with increasing rates of vulvar squamous cell carcinoma in situ, possibly related to increasing rates of HPV infection. Heightened awareness among clinicians may play a role in the increasing frequency of diagnosis; suspicious lesions warrant vulvar biopsy. Pigmented lesions include common nevi, lentigines, melanomas, dysplastic nevi, blue nevi, and a lesion termed atypical melanocytic nevi of the genital type (AMNGT) (232). AMNGTs have some histologic features that may overlap with those of melanoma, but with a benign prognosis.
Vulvar Biopsy A vulvar biopsy is essential in distinguishing benign from premalignant or malignant vulvar lesions, especially because many types of lesions may have a somewhat similar appearance. Vulvar biopsies should be performed liberally in women of reproductive age to ensure that these lesions are diagnosed and treated appropriately. A prospective study of vulvar lesions evaluated by biopsy in a gynecologic clinic found lesions occurring in the following order of frequency: epidermal inclusion cyst, lentigo, Bartholin duct obstruction, carcinoma in situ, melanocytic nevi, acrochordon, mucous cyst, hemangiomas, postinﬂammatory hyperpigmentation, seborrheic keratoses, varicosities, hidradenomas, verruca, basal cell carcinoma, and unusual tumors such as neurofibromas, ectopic tissue, syringomas, and abscesses (233). Clearly, the frequency with which a lesion would be reported after a tissue biopsy is related to the frequency with which all lesions of a given pathology are evaluated in this manner. Thus, this listing probably underrepresents such common lesions as condylomata (Fig. 14.18).
Biopsy is easily performed in the office using a local anesthetic. Typically, 1% lidocaine is infiltrated beneath the lesion using a small (25-to 27-gauge) needle. Disposable punch biopsy instruments come in a variety of sizes from 2 to 6 mm in diameter. These skin biopsy instruments, along with fine forceps, scissors, and a scalpel, should be available in all outpatient gynecologic settings. For smaller biopsies, it is usually not necessary to place a suture. Topical silver nitrate can be used for hemostasis. Multiple tissue samples may be appropriate to obtain representative areas of a lesion if the lesion has a variable appearance or is multifocal. Although the vulvar biopsy procedure involves minimal discomfort, the biopsy sites will be painful for several days after the procedure. The prescription of a topical anesthetic such as 2% lidocaine jelly, to be applied periodically and before urinating, is appreciated by patients who require this procedure. Infection of the site can occur, and patients should be cautioned to report excessive erythema or purulent drainage.
Other Vulvar Conditions Classification and description of intraepithelial lesions of the vulva are presented in Chapter 19.