Vulvar intraepithelial neoplasia

Vulvar intraepithelial neoplasia (VIN) refers to particular changes that can occur in the skin that covers the vulva. VIN is an intraepithelial neoplasia, and can disappear without treatment. VINs are benign but if the changes become more severe, there is a chance of cancer developing after many years, and so it is referred to as a precancerous condition. Medically speaking, the term denotes a squamous intraepithelial lesion of the vulva that shows dysplasia with varying degrees of atypia. The epithelial basement membrane is intact and the lesion is thus not invasive but has invasive potential. The terminology of VIN evolved over several decades. In 1989 the Committee on Terminology, International Society for the Study of Vulvar Disease (ISSVD) replaced older terminology such as vulvar dystrophy, Bowen's disease, and Kraurosis vulvae by a new classification system for Epithelial Vulvar Disease: Nonneoplastic epithelial disorders of vulva and mucosa: Lichen sclerosus Squamous hyperplasia Other dermatoses Mixed neoplastic and nonneoplastic disorders Intraepithelial neoplasia Squamous vulvar intraepithelial neoplasia (VIN), previously classified as VIN 1-3: Non-squamous intraepithelial neoplasia Extramammary Paget's disease Tumors of melanocytes, noninvasive Invasive disease (vulvar carcinoma) The ISSVD further revised this classification in 2004, replacing the three-grade system with a single-grade system in which only the high-grade disease is classified as VIN. VIN is subdivided into: (Robbins Pathological Basis of Disease, 9th Ed) Classic vulvular intraepithelial neoplasia: associated with developing into the warty and basaloid type carcinoma. This is associated with carcinogenic genotypes of HPV and/or HPV persistence factors such as cigarette smoking or immunocompromised states. Differentiated vulvar intraepithelial neoplasia also known as VIN Simplex: is associated with vulvar dermatoses such as lichen sclerosus. It is associated with atypia of the squamous epithelium. The exact cause of VIN is unknown.