Vulvar pathology is located at the border between dermatology and gynaecology. The gynaecologist is concerned by VIN (vulvar intraepithelial neoplasia) lesions as patients meet them for that problem. He makes distinction with dermatologic lesions so as to refer proper patients to dermatologists. A recent classification of VIN has a major interest. One individualizes two kinds of precancerous lesions. The first one is lichen sclerosis with dermatologic treatment by dermocorticoids and the other aetiology is HPV infection with frequent association with cervical localisation. Gynaecologists are more familiar with this second aetiology. Thus, they have to (i) check for VIN, (ii) know their appearance and how the diagnosis can be made by biopsy, (iii) precise the aetiology, (iv) appreciate the severity of the disease, (v) discuss which treatment is indicated: destruction or surgery.