Vulvar Intraepithelial Neoplasia - An Overview

Introduction

The noninvasive squamous lesions that precede vulvar squamous cell carcinoma (SCC) have been termed vulvar intraepithelial neoplasia (VIN). Since there is no particular screening test for VIN, a comprehensive clinical evaluation and biopsy are essential. The appearance of elevated, flat, white, gray, or pigmented lesions serves as the basis for the clinical diagnosis, which is confirmed by biopsy.

A new categorization system for vulvar squamous intraepithelial lesions (SILs) was created in 2015 by the International Society for the Study of Vulvovaginal Disease (ISSVD):

1. Low-grade SIL (LSIL) in the Vulva:

• Also referred to as flat condyloma, Vulvar LSIL, or the human papillomavirus (HPV) effect.

• Previously known as VIN 1.

2. High-grade Vulva SIL (HSIL):

• Referred to as VIN usual type (uVIN) or Vulvar HSIL.

• Previously assigned as VIN 2 and VIN 3.

3. Differentiated VIN (dVIN):

• Formerly recognized as VIN simplex type.

What Is the Difference Between dVIN and uVIN?

VIN comprises uVIN, linked to HPV, and dVIN, linked to chronic inflammation. The classification relies on histology, not HPV testing.

dVIN:

• Represents around five percent of VIN cases.

• Poses a higher risk of progressing to invasive SCC.

uVIN:

• HPV-associated lesion.

• Raises the risk of other anogenital cancers.

• Low-grade lesions treated as condyloma.

• HPV prevalence in VIN (HSIL) ranges from 72 percent to 100 percent, with HPV-16 being the most prevalent type.

What Is the Etiology of Vulvar Intraepithelial Neoplasia?

The specific cause behind VIN is yet unknown. However, most people who are diagnosed with VIN also have a high-risk strain of Human Papillomavirus, which is a sexually transmitted virus that is spread by skin-to-skin contact and can occur via a variety of forms of sexual interaction beyond intercourse. The chance of VIN development is increased by HPV infection. In cases where HPV infection is absent, individuals who develop VIN typically exhibit lichen sclerosis, a condition characterized by inflammation and scaly skin patches on the vulva. High-risk HPV strains 16, 18, and 33 are associated with VIN, with HPV-16 being more prevalent in most cases. A compromised immune system, long-term vulvar inflammation, and tobacco use are the common risk factors for VIN.

What Are the Symptoms of Vulvar Intraepithelial Neoplasia?

While not all cases of VIN show symptoms, those that do may include skin changes such as new growths or pigmentation, as well as vulvar itching (vulvitis), burning, pain, or tingling. Another possible sign is pain during sexual activity. There are several ways that VIN may appear. The most important thing to monitor is changes to the vulvar skin, such as elevated or flat new growths and patches with white, red, pink, gray-brown, or black discoloration. These alterations might affect one particular region of the vulva or several other areas.

What Are the Types of Vulvar Intraepithelial Neoplasia?

Cancer can develop in two VIN types:

• Usual Type VIN (uVIN): Predominant form associated with high-risk HPV infections; often detected in the forties. Known as high-grade squamous epithelial lesions (HSIL), these lesions suggest that the virus can change healthy cells into cancerous ones.

• Differentiated VIN: Around five percent of VIN cases are linked to lichen sclerosis, an inflammatory skin illness that is more common in people 60 years of age and older.

• Low-Grade Squamous Epithelial Lesions. It comprise of abnormal vulvar cells. Low-risk HPV varieties are linked to LSIL and are frequently associated with genital warts. These cells tend to fade away on their own and seldom develop into a malignancy.

What Are the Complications of Vulvar Intraepithelial Neoplasia?

The main concern with VIN is that, if untreated, it may proceed to malignancy. Each VIN type has a different timeline:

• HPV-related VIN, or uVIN: It usually develops into cancer over six to seven years.

• dVIN: Typically, it progresses to cancer in two to three years.

Early intervention is crucial in halting the transition of precancerous cells into cancer cells.

How Is Vulvar Intraepithelial Neoplasia Diagnosed?

Medical practitioners perform a physical examination, inquire about symptoms, and look for any unusual growths or discolorations on the vulva. To improve the visibility of the vulva or vagina, a colposcopy may be performed, utilizing a colposcope, an illuminated tool. A biopsy is essential for a definitive diagnosis of VIN, where a section of the suspicious tissue is extracted for laboratory testing by a pathologist to identify precancerous cells.

How Is Vulvar Intraepithelial Neoplasia Treated?

The goal of treatment is to destroy precancerous cells while preserving vulvar function and sensation. Options include:

• Surgery: Surgery involves the removal of questionable areas; to guarantee total eradication, aberrant cells are usually excised together with a small margin of healthy tissue.

• Laser Ablation: To guarantee thorough treatment, a margin of healthy tissue is removed and hot lasers are used to cut tissue rather than cutting instruments.

• Topical Cream: Imiquimod cream is used topically on the skin to kill abnormal cells.

• Skinny Vulvectomy: This uncommon operation involves removing the vulvar skin in cases when precancerous cells have expanded widely.

Can VIN Be Prevented?

While there is no proven preventive strategy, the most effective way to lower VIN risk is getting the HPV vaccine, offering protection against high-risk HPV strains linked to cervical and vulvar cancer. Additional measures include:

• Practice Safer Sex: While not preventing HPV infections, limiting partners and using barrier methods (e.g., condoms) can reduce risk.

• Address Lichen Sclerosus: Early diagnosis and treatment of lichen sclerosis symptoms can prevent cell damage, reducing the risk of VIN.

• Undergo Regular Paps: Regular Pap smears enable early detection of suspicious tissue for timely intervention. HPV tests during Paps can identify high-risk virus strains.

Conclusion

The possibility of Vulvar Intraepithelial Neoplasia (VIN) developing into cancer highlights the need for early identification. Preventing VIN-related problems and maintaining vulvar health requires routine screenings, HPV vaccination, and timely treatment of associated conditions, including lichen sclerosis.