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. Classification
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, Bowens 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 Pagets 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.
The distress of BDD tends to exceed that of either major depressive disorder or diabetes, and rates of suicidal ideation and attempts are especially high. Causal factors
As with most mental disorders, BDDs cause is likely intricate, altogether biopsychosocial, through an interaction of multiple factors, including genetic, developmental, psychological, social, and cultural. BDD usually develops during early adolescence, although many patients note earlier trauma, abuse, neglect, teasing, or bullying. In many cases, social anxiety earlier in life precedes BDD. Though twin studies on BDD are few, one estimated its heritability at 43%. Yet other factors may be introversion, negative body image, perfectionism, heightened aesthetic sensitivity, and childhood abuse and neglect. Social media
Constant use of social media and "selfie taking" may translate into low self-esteem and body dysmorphic tendencies. The sociocultural theory of self-esteem states that the messages given by media and peers about the importance of appearance are internalized by individuals who adopt others standards of beauty as their own. Due to excessive social media use and selfie taking, individuals may become preoccupied about presenting an ideal photograph for the public. Specifically, females mental health has been the most affected by persistent exposure to social media. Girls with BDD present symptoms of low self-esteem and negative self-evaluation. Researchers in Istanbul Bilgi University and Bogazici University in Turkey found that individuals who have low self-esteem participate more often in trends of taking selfies along with using social media to mediate their interpersonal interaction in order to fulfill their self-esteem needs.