By Corey Whelan 

Published on October 18, 2023

 Medically reviewed by Peter Weiss, MD

Vaginal intraepithelial neoplasia (VaIN) is a precancerous condition caused by cell changes in the lining of the vaginal wall.¹ VaIN is categorized into groups by grade based on the depth and location of the abnormal cells.

VaIN may start within the external surface of the wall of the vagina or spread from areas of nearby cervical dysplasia (abnormal cells in the cervix).² When not treated, these precancerous conditions sometimes escalate into cancer.

This article will explain the differences between VaIN grades. It will also discuss the causes, symptoms, and treatments for this condition.

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Grades of Vaginal Intraepithelial Neoplasia 

The vagina is made up of the following three layers:³

• External (surface) adventitial layer (also called the epithelium)

• Intermediate (middle) muscularis layer

• Internal mucosal layer

VaIN cells are abnormal cells located within the surface layer of the vagina.⁴ They may be classified as low-grade or high-grade, as follows:²

• Low-grade VaIN cells look nearly normal under a microscope. These cells are slow to spread and unlikely to become malignant.

• High-grade VaIN cells look less normal under a microscope. High-grade cells are more likely to spread deeply into the thickness of the epithelium than low-grade cells.

VaIN may also be classified by stage or group.¹

Columbia University Herbert Irving Comprehensive Cancer Center. Vaginal dysplasia.

 VaIN groups are determined by the extensiveness of abnormal cell development and spread. This is sometimes referred to as dysplasia and includes:²

• VaIN 1 (mild dysplasia, or low-grade VaIN): Abnormal cells are located only in the outermost third of the vagina lining's thickness.

• VaIN 2 (moderate dysplasia, or high-grade VaIN): Abnormal cells have spread deeper and can now be found in two-thirds of the vaginal lining's thickness.

• VaIN 3 (severe dysplasia, or high-grade VaIN): VaIN 3 is also referred to as carcinoma in situ. The abnormal cells can be found throughout the entire thickness of the vaginal lining.

VaIN Symptoms

VaIN does not typically cause symptoms.² When symptoms occur, they may be overlooked or mistaken for a different condition, like a vaginal infection.

When they occur, VaIN symptoms may include:¹

• Unusual vaginal discharge

• Bleeding or spotting after vaginal sex

• Vaginal bleeding between periods

VaIN symptoms vary significantly from the symptoms caused by vulvar intraepithelial neoplasia (VIN), another precancerous condition.⁵ Unlike VaIN, VIN causes uncomfortable skin symptoms like itching, burning, and raised lesions. It may also cause pain during vaginal sexual activity.

How Is VaIN Diagnosed?

An abnormal Pap smear may be the first indication that you have VaIN cells. To get a diagnosis, your healthcare provider will recommend a colposcopy.² This outpatient diagnostic test may be done in a healthcare provider's office or ambulatory care clinic.

For this test, a speculum will be inserted into the vagina so your cervix can be fully viewed. A lighted microscope (colposcope) will be used to view your vagina and cervix. The colposcope remains outside the vagina for the entire test duration.

Your cervix will be washed with a type of vinegar solution, which makes it easier to see. The solution application causes a stinging sensation but no pain in most instances.⁶

If the colposcope picks up areas of abnormal cells, a small tissue sample will be removed for biopsy. The excised (cut-out) tissue will be examined under a microscope for cell abnormalities.⁷

Colposcopy typically takes 15 to 20 minutes. This test can be uncomfortable or painful for some people. If a biopsy is done, a topical anesthetic will be applied to the localized area to diminish pain. You may, however, feel a sharp pinch or cramping sensation during the biopsy.

Colposcopy is not usually done under sedation. If you have a condition that indicates the need for anesthesia, such as pelvic floor dysfunction, you and your healthcare provider may determine that using local or general anesthesia makes sense.

How Quickly Does VaIN Progress?

If you're diagnosed with VaIN or any precancerous condition, you may be concerned that it will become cancer. Precancerous conditions can be serious and need to be monitored. However, VaIN rarely progresses into vaginal cancer.⁸

Of the three groups, VaIN 3 is the type most likely to become malignant.⁸ This transformation takes approximately five to 10 years, although it may take less time in some instances.²

Progression rates are also low for low-grade cervical dysplasia (also called cervical intraepithelial neoplasia, or CIN). This condition may cause or coexist with VaIN. If you have high-grade cervical dysplasia and forgo ongoing monitoring tests, you may be more likely to get cervical cancer.⁹

Watchful Waiting for Low-Grade VaIN

Since low-grade VaIN often clears on its own, your healthcare provider may recommend keeping an eye on your condition through testing rather than removing the concerning cells. This is referred to as watchful waiting.¹

You may undergo tests every few months. to see if the cells have regressed (disappeared) or if they've escalated to high-grade VaIN. These tests include:¹

• Pap smear to check for cell changes in the cervix

• Colposcopy to check for cell changes in the vagina, vulva, and cervix

Treatment for High-Grade VaIN

High-grade VeIN is treated surgically. The procedures most commonly used are surgical excision and surgical laser ablation.¹⁰ Both are done under general anesthesia.

Surgical ablation is an outpatient procedure done in a hospital or other facility. During a surgical ablation, a laser is used to burn away the areas of abnormal tissue growth.¹

Surgical excision will be done if it's suspected that VaIN has progressed into vaginal cancer. Surgical excision is more extensive than laser ablation. During the procedure, surgical tools will be used to cut away the concerning areas of tissue. A surrounding margin of normal tissue will also be excised.¹

If there are many suspicious areas, vaginal radiation therapy (also called brachytherapy or internal radiation) may be used instead of or in addition to surgery.

What Causes VaIN Cell Changes?

Certain factors can make you more likely to get VaIN cell changes. But it's not completely clear why one person with risk factors gets VaIN while others with the same risk factors do not.

Human papillomavirus (HPV) infection is the main cause of the cell changes that cause VaIN and cervical dysplasia.¹¹ HPV is a very common sexually transmitted infection (STI) that usually clears on its own.

Some strains of HPV can cause cancer of the vulva, vagina, cervix, and other areas of the body. Factors that diminish your immune system's ability to clear HPV, such as human immunodeficiency virus (HIV) infection, may make you more susceptible to VaIN cell changes.⁹

A history of precancerous or cancerous conditions of the female reproductive tract may also increase your risk, even if you've had a hysterectomy (surgical removal of the uterus).⁹

Follow-Up After VaIN Treatment  

Even after successful treatment, you'll remain vulnerable to VaIN reoccurrences, possibly for your lifetime.¹ For that reason, consistent testing and additional treatment, if necessary, will be essential.

At first, you'll be monitored every few months with tests like a Pap smear and colposcopy. Your healthcare provider may extend the time between tests if you remain asymptomatic.¹¹

Recurrent VaIN Cells and Next Steps 

People with VaIN are at a high risk of recurrence.¹² If VaIN cells recur, you'll need additional treatment to remove them. The surgical procedures that remove high-grade VaIN cells can cause scarring, so they're not often used to treat recurrent VaIN.

If you need additional treatment, your healthcare provider may recommend a topical treatment instead of surgery, such as:¹

• Imiquimod: A topical immunotherapy anti-tumor drug

• Fluorouracil (5-FU): A topical form of the chemotherapy drug

• Estrogen cream

Topical creams are applied within the full vaginal cavity one or more times a week for several months. The cream prescribed for you will determine how it is used.

Severe cases of recurrent VeIN are sometimes treated with vaginal radiation therapy.¹

Summary

Vaginal intraepithelial neoplasia (VaIN) is a precancerous condition of the female reproductive tract. It sometimes manifests along with cervical dysplasia. Both conditions are highly associated with HPV infection.

The immune system often clears VaIN so that the cells disappear without treatment. They may, however, turn into vaginal cancer in some instances. For that reason, monitoring or treatment is essential.