Vulval intraepithelial neoplasia (VIN)

Vulval intraepithelial neoplasia (VIN) is a skin condition of the vulva.

The vulva is the area between a woman’s legs that includes the female external sex organs.

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 

Intraepithelial - 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 3 types of VIN:

• low grade squamous intraepithelial lesion (LSIL)
• high grade squamous intraepithelial lesion (HSIL)
• differentiated VIN (dVIN)

You may also hear the terms VIN 1, VIN 2, or VIN 3. This is how doctors used to classify vulval intraepithelial neoplasia. The grades VIN 1, VIN 2, and VIN 3 refer to how deeply the abnormal cells go into the surface layer of the skin.

If the abnormal cells break through the basement membrane into the deeper tissue, it is classed as vulval cancer.

High grade squamous intraepithelial lesion (HSIL)

This is the most common type of VIN. Many women who have it have ongoing infections with high risk types of HPV. It occurs mainly in women aged 35 to 49 and is more common in women who smoke or have a weak immune system. 

VIN 2 and VIN 3 is now called high grade squamous intraepithelial lesion (HSIL). 

You usually have treatment for high grade squamous intraepithelial lesion (HSIL). This is because there is a risk that the abnormal cells may develop into cancer over time. But the risk is low. 
 

Low grade squamous intraepithelial lesion (LSIL)

VIN 1 is now called low grade squamous intraepithelial lesion (LSIL). LSIL is generally a mild abnormality. It is usually caused by low risk types of the human papilloma virus (HPV). These low risk types can cause warts in this area. They are not cancerous and usually go away without treatment.

You may have regular follow up appointments to check that they are getting better.

Differentiated VIN (dVIN)

This is an uncommon type of VIN and tends to develop in women between 50 and 60 years of age. It is rarely linked to HPV infection.

It is commonly found in women who have a vulval condition called lichen sclerosus. This is inflammation of the skin causing itchy, white patches.  

Differentiated VIN has a higher risk of developing into a cancer than high grade squamous intraepithelial lesion (HSIL). So surgery is usually the best treatment for this type of 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.

Tests to diagnose VIN

Your GP may refer you to a specialist at the hospital. You would normally see a doctor who specialises in gynaecological conditions (gynaecologist) or skin conditions (dermatologist).

The specialist examines your vulva in a private room in the outpatient clinic. They 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. This might be on the same day as your appointment or booked for another day.  

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.

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

You usually have treatment for high grade squamous intraepithelial lesions (HSIL) and differentiated VIN (dVIN). 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.

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 may suggest you have surgery.

Imiquimod cream

Research has shown that a cream called imiquimod works well in around half (50%) of women with high grade squamous intraepithelial lesions (HSIL). This cream works by stimulating the immune system. This means it uses the body's natural defences to kill the HPV. Doctors hope that if the cream destroys the HPV, the cells affected by VIN will go back to normal. 

You usually apply the cream to the affected area 3 to 4 times per week, and it can take up to 6 months to work. Inflammation of the vulval skin is a common side effect of this treatment.

Laser treatment

Some specialists use a laser to burn the abnormal cells away. Your doctor may call this laser ablation. Most people only usually need one treatment. You may have this treatment if you have high grade squamous intraepithelial lesions.

Sometimes you might have laser treatment if surgery is not suitable. 

Laser treatment to the vulval can cause:

• hair loss around the vulva
• changes in skin colour around the vulva

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. Sometimes you might have a combination of laser treatment and surgery.  

Your surgeon might need to carry out a different operation if your VIN is more widespread. This is called a skinning vulvectomy and 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 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 the skin has been removed. A skin graft is a sheet of skin that your surgeon removes from another part of your body (donor site). 

Your specialist will explain in detail what treatment is best for you.

Looking after your vulva

Symptoms 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 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. Follow up is usually for many years. This is because there is a risk that the VIN may return after treatment. Your doctor might also suggest that you examine yourself routinely. This is called self examination.

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