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.

[1] Medically speaking, the term denotes a squamous intraepithelial lesion of the vulva that shows dysplasia with varying degrees of atypia.

VIN is subdivided into: (Robbins Pathological Basis of Disease, 9th Ed) Classic vulvar intraepithelial neoplasia: associated with developing into the warty and basaloid type carcinoma.

In the Usual type VIN, seen more frequently in young patients, lesions tend to be multifocal over an otherwise normal vulvar skin.

In the differentiated type VIN, usually seen in postmenopausal women, lesions tend to be isolated and are located over a skin with a vulvar dermatosis such as Lichen slerosus.