Approximately 90% of vulvar cancers are squamous cell carcinoma. About 5% are melanoma, 4% adenocarcinoma, 2% sarcoma, and 1% basal cell carcinoma. The cause has not been identified, but a sexually-transmitted disease such as human papilloma virus (HPV, or genital warts) may play a role. Vulvar cancer is relatively rare, accounting for about 5% of all gynecological cancers and less than 1% of all new cancers in women. Cancer of the vulva usually occurs in postmenopausal women with peak incidence between the ages of 65 and 75. However, 15% of the cases occur in women 40 or younger. Risk factors include previous HPV infection, previous cervical cancer or vaginal cancer, syphilis infection, diabetes, obesity, and hypertension. Early lesions of the vulva that may change into vulvar cancer are called vulvar intraepithelial neoplasia.
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