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Vulval intraepithelial neoplasia (VIN)

Find out what vulval intraepithelial neoplasia is, its symptoms and treatment options.

What it is

Vulval intraepithelial neoplasia (VIN) is a skin disease. Abnormal cells develop in the surface layers of the skin covering the vulva. It is not vulval cancer but could turn into a cancer. This may take many years. Some doctors call it pre cancer although many women with VIN will not develop cancer.

VIN stands for:

Vulval - you can get VIN anywhere on the vulva and you may have it in more than one place 

Intrepithelial - the abnormal cells are contained within the top layer of skin (epidermis) that covers the vulva

Neoplasia - the cells in the skin are abnormal 

Types of VIN

There are 2 types of VIN:

  • usual type VIN
  • differentiated VIN

Usual type VIN

This is the most common type of VIN. Many women who have it have ongoing infection with high risk types of HPV (human papilloma virus). It occurs mainly in women aged 30 to 40 and is more common in women who smoke. 

There are different ways to classify usual type VIN. Your doctor might describe it as:

  • VIN 1, VIN 2, or VIN 3
  • low grade or high grade  

The grades VIN 1, VIN 2, and VIN 3 refer to how deeply the abnormal cells go into the surface layer of the skin. VIN 1 means less than a third of the skin covering the vulva has abnormal cells. VIN 2 means less than two thirds of the skin has abnormal cells. VIN 3 means more than two thirds of the skin covering the vulva has abnormal cells. 

VIN 1 (low grade VIN) is generally a mild abnormality and usually goes away by itself. It is no longer classified as VIN as there is no clear link between it and vulval cancer. Nowadays doctors group VIN 2 and VIN 3 together. The refer to them both as high grade VIN. 

VIN is always contained in the top layer of the skin covering the vulva. If the abnormal cells break through the basement membrane into the deeper tissue, it is classed as vulval cancer.

Diagram showing the stages of VIN

Treatment

You usually have treatment for high grade VIN (VIN 2 or 3). This is because there is a risk that the abnormal cells may develop into cancer over time. But the risk is low. 

VIN 3 used to be called stage 0 vulval cancer or carcinoma in situ (CIS). But these days stage 0 is no longer classed as an invasive cancer. 

Differentiated VIN

This is an uncommon type of VIN and tends to occur in women between 50 and 60 years of age. It is not linked to HPV infection, but is commonly found in women who have a vulval condition called lichen sclerosus. 

Lichen sclerosus is inflammation of the vulval skin. 

Differentiated VIN has a higher risk of developing into a cancer than usual type VIN. 

Symptoms of VIN

The symptoms of VIN vary between women. Some have no symptoms. But some women have severe symptoms. These may include

  • itching
  • pain
  • changes to the vulval skin
  • discomfort or pain during sex

All these symptoms can be caused by other conditions, such as infection. But if you have any of these symptoms, you should see your doctor. They can examine your vulva.

Tests to diagnose VIN

Your specialist examines your vulva in a private room in the outpatient clinic.

They might use a speculum and colposcope to see inside your vulva and vagina. A speculum is a metal or plastic instrument that opens the walls of the vagina for an internal examination.   A colposcope is like a microscope that helps the doctor to find any abnormality that is too small to see with the naked eye.

Your doctor may be able to see areas of white, red or brown on the vulva. The only way to know for certain if it is VIN is to take a sample of tissue. This is called a biopsy. Before taking a biopsy the doctor numbs the area with local anaesthetic.

You usually go back to the clinic to get the results of your biopsy. It can take about 2 weeks for the results to be ready. If you do have VIN the doctor will tell you about your treatment options.

Treatment options

Your treatment depends on where the VIN is, your symptoms, and the risk of it developing into cancer. Your doctor may offer you

  • no treatment, and follow you up closely
  • treatment with a cream called imiquimod
  • laser treatment
  • surgery

Until recently, the most common treatment for VIN was surgery. But surgery has physical and psychological effects. So doctors have been looking for alternatives to surgery.

Your doctor will talk to you about the risk of your VIN turning into cancer. They might recommend surgery if they think you have a higher risk of developing cancer.

Close follow up

For some women the risk of developing cancer is very low. So if you don’t have any symptoms, you might decide not to have any treatment. Your doctors will monitor you closely. If your VIN does start to turn into cancer, the doctor will offer you surgery.

Imiquimod cream

Research has shown that a cream called imiquimod works well in around half (50%) of women with VIN. This cream works by stimulating the immune system. This means it uses the body's natural defenses to kill the HPV. Doctors hope that if the HPV is destroyed, the cells affected by VIN will go back to normal. It can take up to 6 months to work and may have side effects.

Laser treatment

Some doctors use a laser to burn the abnormal cells away. This may be painful. There might be a higher risk of the VIN coming back than with other types of treatment.

Surgery for VIN

Your surgeon removes all the skin affected by VIN. Even if you have more than one area of VIN, this is usually possible. The operation is called a wide local excision. You might have a combination of laser surgery and regular surgery.

Rarely, if the VIN is very widespread, your surgeon might need to do an operation called a skinning vulvectomy. This removes the skin over a large area. You may need a skin flap (or less often a skin graft) to repair the area, but your surgeon will avoid doing this if at all possible.

A skin flap is an area of healthy skin with its blood supply, which is moved from close by. It covers the area where skin has been removed.

Looking after your vulva

If you have symptoms, these usually improve after treatment for VIN. Your doctor or nurse will tell you how to care for the sensitive skin on your vulva, and what you can do to reduce symptoms. 

Follow up

You have regular check ups in the hospital clinic. At first your follow up appointments are every few months. But if all is well, they gradually become less and less frequent. At these appointments your doctor examines your vulva. They monitor you closely to check there are no signs that the VIN has come back.

Your doctor might also suggest that you examine yourself routinely. This is called self examination.

If you have any problems or concerns between your appointments, it is important to tell your doctor or nurse right away. You don’t have to wait until the next appointment.

Last reviewed: 
06 Jul 2016
  • 2014 UK National Guideline on the Management of Vulval Conditions

    British Association for Sexual Health and HIV

  • 2014 UK national guideline on the management of vulval conditions

    S Edwards and others (2015) 

    International journal of sexually transmitted diseases and AIDS Aug;26(9):611-24

  • Activity, safety, and feasibility of cidofovir and imiquimod for treatment of vulval intraepithelial neoplasia (RT³VIN): a multicentre, open-label, randomised, phase 2 trial

    A Tristram and others (2014) 

    The lancet oncology Nov;15(12):1361-8

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