Presented below is an adaptation of the histologic classification of vulvar disease and precursor lesions of cancer of the vulva developed by the International Society for the Study of Vulvar Disease.

Non-neoplastic epithelial disorders of skin and mucosa

• Lichen sclerosus (lichen sclerosus et atrophicus).
• Squamous cell hyperplasia (formerly hyperplastic dystrophy).
• Other dermatoses.

Classification of vulvar intraepithelial neoplasia (VIN)

1. Mild dysplasia (formerly mild atypia).
2. Moderate dysplasia (formerly moderate atypia).
3. Severe dysplasia (formerly severe atypia).
4. Carcinoma in situ.

Paget disease of the vulva

• Characteristic large pale cells in epithelium and skin adnexa.

Other histologies

• Basal cell carcinoma.
• Verrucous carcinoma.
• Sarcoma.
• Histiocytosis X.
• Malignant melanoma.