Both vulvar intraepithelial neoplasia (VIN) and vaginal intraepithelial neoplasia (VAIN) are rare and poorly reported.VIN and VAIN are often multicentric and, as with CIN, HPV infection is an important cause. HPVDNA can be detected in all VINIII (93% with HPV-16DNA detected), all VAIN (75% with HPV-16DNA) and 96% of CIN (73% with HPV 16DNA). I. Pathological features of vulvar and vaginal intraepithelial neoplasia In recent years, there has been a trend towards younger and increasing vulvar and vaginal intraepithelial neoplasia. The former has an age of onset of 30 to 50 years, while the latter is more common in women over 60 years of age. The pathology of vulvar and vaginal intraepithelial neoplasia is characterized by abnormal cell growth, deep-stained nuclei, nuclear heterogeneity, disorganized cell arrangement, loss of polarization, frequent nuclear fission, and non-diploid DNA karyotype. Clinical diagnosis and treatment of vulvar and vaginal intraepithelial neoplasia 1. Patients with vulvar intraepithelial neoplasia mainly present with vulvar pruritus, burning sensation, vulvar lesions, ulcers, papules, spots or warts. Vaginal intraepithelial neoplasia may be associated with increased vaginal discharge or post-contact vaginal bleeding. Diagnosis relies on local lesion biopsy pathology, and multi-point biopsy should be performed on suspicious areas. Colposcopic localization of biopsies can help to improve the accuracy of pathological diagnosis. 2. Treatment (1) Observation: For VINI or VAINI, young, asymptomatic, with follow-up conditions or in case of pregnancy. If the lesion worsens during observation, or if there is no improvement after 6 to 12 months of observation, it should be treated. (2) Pharmacological treatment: 5FU topical treatment is commonly used. (3) Physical therapy: CO2 laser, freezing and LEEP, high-energy focused ultrasound knife and other treatment methods can be used for early lesions. (4) Surgical treatment: surgical excision of lesions is the main treatment method. Depending on the lesions, local extensive excision of lesions, peeled vulvectomy and simple vulvectomy are feasible. Surgery should consider both complete excision of the lesion and reconstruction of vulva or vagina to restore normal sexual life. Prognosis of vulvar and vaginal intraepithelial neoplasia The malignant process of VIN and VAIN is slow and often degenerates VAIN progresses to invasive carcinoma in 9%, persists in 13%, and regresses in 78% of cases at 3 years of follow-up. Notably, 2-8% of VINIII may be combined with an invasive tumor. vain III is often combined with multifocal occult vulvar carcinoma and has a 3-fold increased risk of recurrence if surgical margins are not cleared.