Vulvar cancer is a malignant, invasive growth in the vulva, or the outer portion of the female genitals. The disease accounts for only 0.6% of cancer diagnoses but 5% of gynecologic cancers in the United States. The labia majora are the most common site involved representing about 50% of all cases, followed by the labia minora. The clitoris and Bartholin glands may rarely be involved. Vulvar cancer is separate from vulvar intraepithelial neoplasia (VIN), a superficial lesion of the epithelium that has not invaded the basement membrane—or a pre-cancer. VIN may progress to carcinoma-in-situ and, eventually, squamous cell cancer.