Precancerous conditions of the vulva

Precancerous conditions of the vulva are changes to vulvar cells that make them more likely to develop into cancer. These conditions are not yet cancer. But if they aren’t treated, there is a chance that these abnormal changes will become vulvar cancer.

Vulvar intraepithelial neoplasia (VIN) means abnormal changes to the epithelial cells in the top or surface layer of skin that covers the vulva. VIN is also known as lower anogenital squamous intraepithelial lesion.

There are 2 types of VIN based on whether or not they are linked to human papillomavirus (HPV) infection.

HPV-associated VIN, also known as usual-type VIN, is linked to HPV infection. It’s the most common type of VIN. It’s more common in people aged 35 to 55.

HPV-associated VIN is divided into 2 subtypes based on its grade.

• Low-grade squamous intraepithelial lesion (LSIL) is usually caused by an infection with a low-risk type of HPV, such as type 6 or 11. It normally goes away on its own and doesn’t cause cancer. LSIL used to be called VIN 1.
• High-grade squamous intraepithelial lesion (HSIL) is usually caused by an infection with a high-risk type of HPV, such as type 16, 18, 31 or 33. HSIL can become cancer, so it often requires treatment. HSIL used to be called VIN 2 or VIN 3.

If an HPV-associated VIN develops into cancer, it becomes the basaloid or warty squamous cell carcinoma (SCC) of the vulva.

HPV-independent VIN, also known as differentiated-type VIN (d-VIN), is less common. It usually occurs in older people aged 55 to 85.

HPV-independent VIN is not linked to HPV infection, but it often occurs when there is lichen sclerosus (a skin condition). Lichen sclerosus can make skin itchy and cause white patches due to inflammation. The skin may also become thinner and paler than usual. The vulva may look abnormal.

If HPV-independent VIN develops into cancer, it becomes keratinizing SCC of the vulva. HPV-independent VIN tends to develop into cancer faster than HPV-associated VIN.

The following risks increase your chance of developing VIN:

• HPV infection
• lichen sclerosus
• smoking
• immunosuppression

Find out more about HPV.

Up to 40% of VIN cases don’t cause symptoms. They are diagnosed when having tests for other health problems.

The signs and symptoms of VIN include:

• itching in the vulva that doesn’t go away or get better over time
• soreness, burning or severe tingling in the vulva that can become worse when urinating
• some areas of the vulvar skin appearing white, red, pink, gray, brown or black
• thickened vulvar skin
• discomfort or pain during sex caused by ulcers and nodules on the skin

If you have symptoms or your doctor thinks you might have VIN, you will be sent for tests. Tests used to diagnose VIN may include:

• an examination of the vulva, vagina, cervix and anus
• a colposcopy of any abnormal areas of the vulva
• a biopsy

Treatment options for VIN include:

• no active treatment with close follow-up (watchful waiting)
• topical therapy (an ointment or cream) such as imiquimod (Aldara, Zyclara) or fluorouracil (5-fluorouracil or 5-FU)
• laser surgery to burn the abnormal cells away
• a wide local excision to remove the area of skin affected by VIN and some healthy tissue around it (called the surgical margin)

Find out more about surgery for vulvar cancer.

If you have been treated for VIN, there is a risk that it will come back (recur). You will have regular follow-up visits, usually every few months. These visits will happen less often if there are no problems. Report any concerns and signs or symptoms to the doctor without waiting for your next scheduled visit.