Vulval intraepithelial neoplasia (VIN)

Vulval intraepithelial neoplasia or VIN is when abnormal cells develop in the top layer of skin covering the vulva. It is not vulval cancer but could turn into cancer. This may take many years.

Some doctors call VIN a pre cancer although many women with VIN will not develop cancer. It is also called vulvar intraepithelial neoplasia. 

What causes VIN?

Doctors don’t know for sure what causes VIN. There are some factors that can increase your risk of developing VIN. Having one or more of these risk factors doesn’t mean you will definitely develop VIN.

Risks factors include:

• infection with the human papilloma virus (HPV)
• smoking
• having problems with your immune system such as HIV
• long term skin problems such as lichen sclerosis

Types of VIN

There are 2 main types of VIN:

• usual or classical VIN. This includes low grade squamous intraepithelial lesions (LSIL) and high grade squamous intraepithelial lesions (HSIL)
• differentiated VIN (dVIN)

Usual or classical VIN

This is the most common type of VIN. It includes:

• low grade squamous intraepithelial lesion (LSIL)
• high grade squamous intraepithelial lesion (HSIL)

You may also hear the terms VIN 1, VIN 2, or VIN 3. This is how doctors used to classify VIN. They now use the terms LSIL or HSIL.

LSIL and HSIL 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.

Usual or classical VIN is caused by human papilloma virus (HPV) infections.

Low grade squamous intraepithelial lesion (LSIL)

You may also hear LSIL being called VIN 1.

LSIL is usually caused by infections with low risk types of 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.

High grade squamous intraepithelial lesion (HSIL)

HSIL is also called VIN 2 and VIN 3. It is usually caused by infections with high risk types of HPV. 

You usually have treatment. This is because there is a risk that the abnormal cells may develop into cancer over time. Treatment is usually surgery or a cream.  

Differentiated VIN (dVIN)

This is the less common type of VIN. It usually develops in older women than HSIL and LSIL. The average age of diagnosis is around 68.

Differentiated VIN is not linked to HPV infection. It is commonly found in women who have a vulval condition called lichen sclerosis. This is inflammation of the skin that causes itchy and white patches.  

Differentiated VIN has a higher risk of developing into cancer than HSIL. Doctors usually recommend you have surgery to prevent vulval cancer from developing.

Symptoms of VIN

Symptoms of VIN can vary. Some women have no symptoms. But some have symptoms such as:

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

All these symptoms can be caused by other conditions. It’s important to see your GP if you have any of these symptoms.

Tests to diagnose VIN

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

The specialist examines you in a private room, in the outpatient clinic. The only way to know for certain if it is VIN is to take a sample of tissue. This is a biopsy. You might have a biopsy on the same day as your appointment or booked for another day. Your doctor will numb the vulval area with a local anaesthetic before taking the biopsy. 

You usually go back to the clinic to get your biopsy results. It usually takes about 2 weeks.

Treatment options

Your treatment depends on:

• where the VIN is
• your symptoms
• the risk of it developing into cancer

Your doctor may suggest you have monitoring instead of treatment straight away. This is usual for low grade squamous intraepithelial lesion (LSIL) or VIN 1.

You usually have treatment for high grade squamous intraepithelial lesion (HSIL) and differentiated VIN. Treatment includes:

• surgery
• treatment with a cream called imiquimod
• laser treatment

Monitoring and close follow up

For LSIL, the risk of developing cancer is very low. So if you don’t have any serious symptoms, you might choose not to have treatment.

Your doctor will monitor you closely. You can then have treatment if there is any sign that your VIN has started to change.

Surgery for VIN

Your surgeon removes all the skin affected by VIN. This is a wide local excision.

You may need a different operation if your VIN is more widespread. This is a skinning vulvectomy.

Imiquimod cream

This cream works by stimulating the immune system to kill the HPV. The cells affected by VIN will then go back to normal. 

You usually start applying the cream to the affected area once a week. You then slowly increase it to 3 times per week. It can take 3 to 4 months to work.

Imiquimod cream can cause side effects. The most common side effect is inflammation of the vulval skin. This can cause the skin to:

• become red, sore and itchy
• weep, peel or crack

Laser treatment

Some doctors may suggest using a laser to burn the abnormal cells away, but this is rare. This is also called laser ablation. Most people only need one treatment.

Laser treatment for VIN can cause:

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

Looking after your vulva

Symptoms usually improve after treatment. Your doctor or nurse will tell you how to care for the sensitive skin on your vulva.

Follow up

You have regular check ups at the hospital. 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 that there are no signs that the VIN has returned.

You usually have check ups 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.

Coping with VIN

Coping with a diagnosis of VIN can be difficult. Some of the tests and treatments you have can make you feel uncomfortable and embarrassed. Your GP or specialist will try to make you as comfortable as possible.

You can ask for a chaperone to be in the room with you during any test or appointment you may have. A chaperone can be a friend or relative, or a trained health professional such as a practice nurse or a specialist nurse.