Vulvar intraepithelial neoplasia.

Vulvar intraepithelial neoplasia (VIN) is a high-grade intraepithelial squamous lesion and precursor of invasive squamous cell carcinoma (SCC). The 2004 International Society for the Study of Vulvovaginal Disease (ISSVD) classification distinguished two types of VIN: usual type (human papillomavirus (HPV)-related) and differentiated type (not HPV-related). The incidence of usual-type VIN is higher in younger women, while differentiated-type VIN is more common in older patients with chronic dermatologic conditions. Differentiated-type VIN has a greater invasive potential and shorter time between diagnosis and SCC than usual-type VIN. The diagnosis of VIN is carried out by identifying a lesion by visual inspection and confirming by performing a biopsy. Screening tests are not available. Patients with usual-type VIN are at a higher risk of developing another HPV-related malignancy of the anogenital tract; therefore, examination from the cervix to the perianal area is mandatory. The therapeutic approach to VIN balances the invasive potential with the need to be as conservative as possible. Current prophylactic HPV vaccines offer protection against usual-type VIN and related invasive carcinoma.