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 may become vulvar cancer.

Vulvar intraepithelial neoplasia (VIN)

Vulvar intraepithelial neoplasia (VIN) means changes to the epithelial cells in the top or surface layer of skin that covers the vulva.

Usual-type VIN is the most common type of VIN. It is more common in younger women aged 35 to 55 and is linked to the human papillomavirus (HPV) infection. If usual-type VIN changes to squamous cell carcinoma, it becomes the basaloid or warty subtype.

Differentiated-type VIN is less common. It usually occurs in older women aged 55 to 85. It is not linked to HPV infection but can occur along with skin conditions of the vulva such as lichen sclerosis. If differentiated-type VIN changes to squamous cell carcinoma, it becomes the keratinizing subtype.

Grades of VIN

The grade of VIN means how deep the abnormal cells go into the top layer of the skin that covers the vulva.

  • VIN 1 means that the depth of abnormal cells is less than one-third of the top layer of vulvar skin.
  • VIN 2 means that the depth of abnormal cells is less than two-thirds of the top layer of vulvar skin.
  • VIN 3 means that the depth of abnormal cells is more than two-thirds of the top layer of vulvar skin.

VIN 1 is low grade and usually goes away on its own.

VIN 2 and VIN 3 are often grouped together as high-grade VIN and usually require treatment.

Risk factors

One of the most common risk factors of VIN is HPV infection. Other risk factors include:

  • smoking
  • immunosuppression
  • lichen sclerosis

Find out more about HPV.


Some women have no symptoms of VIN and are diagnosed when having tests for other health problems. The signs and symptoms of VIN may include:

  • itching in the vulva
  • soreness, burning or severe tingling in the vulva that can become worse when urinating
  • changes to the vulvar skin such as red, white or discoloured areas, warty appearance or areas of thick skin
  • discomfort or pain during sex


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:

  • exam of the vulva, vagina, cervix and anus
  • colposcopy
  • biopsy


Treatment options for VIN include:

  • no treatment with close follow-up
  • topical therapy (an ointment or cream) with imiquimod (Aldara, Zyclara) or fluorouracil (5-fluorouracil or 5-FU, Efudex)
  • laser surgery
  • surgical removal with a wide local excision or a simple vulvectomy

Follow-up after treatment for VIN

Women who have been treated for VIN have 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.

Expert review and references

Medical disclaimer

The information that the Canadian Cancer Society provides does not replace your relationship with your doctor. The information is for your general use, so be sure to talk to a qualified healthcare professional before making medical decisions or if you have questions about your health.

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