Vulvar Intraepithelial Neoplasia (VIN) : Risks, Symptoms, and Treatment

1. What is Vulvar Intraepithelial Neoplasia (VIN)?

   Vulvar intraepithelial neoplasia is a precancerous condition that is characterized by the presence of abnormal cells within the epithelial layer of the vulva, which is the external female genitalia.⁽¹⁾ A person with Vulvar intraepithelial neoplasia may notice lesions or patches of discoloration on the vulva, which may also feel itchy.

   Vulvar intraepithelial neoplasia is considered a precursor to vulvar cancer and is often associated with persistent infection by high-risk types of the human papillomavirus. Vulvar intraepithelial neoplasia may increase the risk of development of vulvar cancer.⁽³⁾ According to the American Cancer Society, in 2023 approximately 6470 females in the United States received vulvar cancer diagnosis.⁽⁴⁾

   Vulvar intraepithelial neoplasia is sometimes graded by doctors according to the severity as VIN 1 VIN 2 and VIN 3. This indicates a more severe form of VIN progressing towards cancer.⁽²⁾

2. Significance of Understanding Vulvar Intraepithelial Neoplasia (VIN)

   Understanding vulvar intraepithelial neoplasia holds significant importance for various reasons: 

   • Vulvar intraepithelial neoplasia is considered a precursor to vulvar cancer. Having an understanding of this condition allows for early intervention preventing progression. It helps healthcare professionals implement preventive measures and surveillance strategies to manage and reduce the risk of vulvar cancer.
   • It helps healthcare providers in determining appropriate diagnostic and treatment strategies. Management plans can be tailored, based on the grade and extent of VIN.
   • Having knowledge about Vulvar intraepithelial neoplasia empowers patients to actively participate in their healthcare.
   • Awareness of Vulvar intraepithelial neoplasia is to raise public consciousness about the risk associated with persistent HPV infections and the importance of preventive measures.
   • A comprehensive understanding of Vulvar intraepithelial neoplasia contributes to ongoing research efforts aimed at improving diagnostic methods, treatment modalities, and preventive strategies.

Vulvar intraepithelial neoplasia is of two different types: 

• Usual Type Vulvar Intraepithelial Neoplasia (uVIN): It is associated with human papillomavirus (HPV). It does not typically progress to vulvar squamous cell carcinoma (VSCC). However, if an individual does not receive treatment within 6-7 years, the risk of developing cancer increases.⁽³⁾
• Differentiated Vulvar Intraepithelial Neoplasia (dVIN): This is a rare type than uVIN. People with dVIN are more likely to develop vulvar cancer specifically vulvar squamous cell carcinoma, if appropriate treatment is not provided. dVIN is associated with skin conditions including lichen sclerosus and lichen planus, not HPV.

Based on abnormal cell changes vulvar intraepithelial neoplasia is graded as follows: 

• VIN 1 (Low-grade Squamous Intraepithelial Lesion or LSIL): It is characterized by mild dysplasia or low-grade changes in the squamous epithelial cells of the vulva. These cells are mildly abnormal but have a lower risk of progressing to invasive cancer as compared to higher-grade lesions. Conservative management approaches can be used along with regular follow-ups.
• VIN2 (High-grade Squamous Intraepithelial Lesion of HSIL): It involves more significant abnormalities in the squamous epithelial cells, indicating moderate to severe dysplasia. There is an increased risk of progression to invasive cancer compared to VIN 1. More aggressive intervention is needed for the management of VIN 2 which includes surgical excision and ablative therapies.
• VIN 3 (Carcinoma in Situ): This represents a more severe form of vulvar intraepithelial neoplasia. Here there is full-thickness involvement of squamous epithelium by abnormal cells. It is often referred to as carcinoma in situ as the abnormal cells are confined to the surface layers and have not invaded deeper tissues. VIN 3 is more likely to progress to invasive cancer. Prompt and definitive treatment is typically recommended. The treatment options include surgical excision, laser therapy, or vulvectomy. 

Vulvar intraepithelial neoplasia is associated with persistent infection by high-risk types of human papillomavirus (HPV). Its presence increases the risk of developing vulvar cancer if left untreated. Classifying it into different grades guides healthcare providers in determining the appropriate level of intervention and surveillance for individuals diagnosed with vulvar intraepithelial neoplasia.

Most individuals do not experience any symptoms of VIN.⁽⁴⁾ Healthcare providers may notice changes in the vulva during routine appointments, such as Pap smear.⁽⁵⁾

If symptoms are experienced, they may include: 

• Pruritis or persistent itching of the vulvar region. It may not always correlate with visible external lesions.
• Pain and discomfort during intercourse or with certain activities involving friction or pressure on the vulva.
• Burning sensation in the vulvar area.
• Visible change includes redness, discoloration, and the presence of thickened areas in the skin of the vulva.
• VIN lesions may appear as white, red, or pigmented areas on the vulva.

The lesions may occur in any part of the vulva but are commonly found on labia minora, labia majora, and perineum.

The exact cause of VIN is not known but there are a few factors that may be linked to this condition. It is known to occur more in white females who are in their forties.⁽³⁾ These risk factors include: 

• Having human papillomavirus infection
• Suffering from a condition that may weaken the immune system
• Taking medications that are known to weaken the immune system
• Having lichen sclerosis, a condition that affects the skin of the vulva
• Smoking
• Changes in hormonal levels, especially those occurring during menopause may increase the risk of the development of VIN
• A person with a history of vulvar cancer or previous vulvar intraepithelial neoplasia has a higher risk of developing VIN

It is important to note that the primary cause of Vulvar intraepithelial neoplasia is HPV infection. Other factors may act as co-factors in the development of this condition.

While diagnosing Vulvar intraepithelial neoplasia, the doctor discusses any visible symptoms that may be noticed in the vulva. If Vulvar intraepithelial neoplasia is suspected they would further examine the vulva using colposcopy to get a clearer view of the lesions.⁽⁶⁾ Also, they may examine the anus, cervix, and vagina.⁽⁷⁾

Colposcopy may help rule out any other condition that has similar symptoms.

After colposcopy, the doctor may order a biopsy. In a biopsy, a skin sample is taken and sent to the laboratory.⁽⁷⁾ The pathologist examines the sample under a microscope and looks for specific changes to the cells, which may indicate whether or not a person has Vulvar intraepithelial neoplasia.

There are several treatment options for Vulvar intraepithelial neoplasia, each of which depends on the symptoms and cancer risk.

The various options include: 

• Watchful Waiting or Monitoring: Some of the cases may resolve even without treatment. In such cases, the doctor may monitor symptoms, instead of removing the lesion and exposing individuals to further health risks.
• Removal of Lesions: To remove lesions cold knife surgery and electrosurgical excision procedure can be used for both uVIN and dVIN.⁽³⁾ Laser surgery may be another option, particularly for CO2 laser ablation.
• Topical Treatments: In cases, where a person may not be able to undergo surgery, topical treatment may play a role in reducing symptoms.⁽⁸⁾ One of the topical chemotherapy treatments is fluorouracil (5-FU), which can be directly applied to the vulva. Imiquimod is another option that works by boosting the immune system to clear the lesion. This is not a form of chemotherapy treatment.
• Other Options: Antiviral medication can help reduce the number of cells HPV has affected. Also, photodynamic therapy can reduce these cells by using light-sensitive medication and a light source to trigger cell death.

Regular follow-up care is crucial to monitor the response to treatment and detect any recurrence or progression of Vulvar intraepithelial neoplasia. Pap smear and colposcopy may be performed during follow-up visits to assess the health of the vulvar tissue.

HPV vaccine is the only option that can prevent the occurrence of VIN. The number of females with VIN has gone down since the introduction of this vaccine.⁽³⁾

According to the Centers for Disease Control and Prevention (CDC), children at age of 11-12 years should receive two doses of HPV vaccine. These doses should be given in the gap of 6-12 months.⁽⁹⁾

Practicing safe sex can reduce the risk of HPV transmission. Regular pelvic check-ups are crucial for early detection and monitoring of any changes in the vulvar tissue.

Quitting smoking can also contribute to overall health and reduce the risk of various cancers.

Early detection through regular screening and prompt medical attention for symptoms can contribute to the effective management and prevention of Vulvar intraepithelial neoplasia.

Vulvar intraepithelial neoplasia is a precancerous condition that develops in a person’s vulva. A person with HPV is at an increased risk of this condition. Other conditions including lichen sclerosus can increase the risk.

Itching and burning lesions are the typical symptoms of VIN. These lesions may be discolored compared with the rest of the skin. Most of the individuals do not experience any symptoms at all.

Treatment of Vulvar intraepithelial neoplasia may depend on the symptoms and risk of cancer. For mid symptoms watchful waiting may be the best course of action. If lesions do not go away on their own, surgery, and laser ablation are more suitable options.

By implementing these strategies, significant steps can be taken toward maintaining vulvar health and reducing the burden of associated cancer.