Vulvar intraepithelial neoplasia (VIN) is a skin condition with abnormal cell changes on the surface of the vulva. The vulva consists of the external female genital organs, including the labia majora and labia minora. “Intraepithelial” means the changes are in the top layer of skin, and “neoplasia” refers to this abnormal growth. VIN is a precancerous condition, not invasive cancer. This means some skin cells are atypical and could develop into vulvar cancer without treatment.
Types, Causes, and Risk Factors
The most common form is High-Grade Squamous Intraepithelial Lesion (HSIL), which is strongly associated with persistent infection by high-risk types of the Human Papillomavirus (HPV). Certain high-risk HPV strains can cause cellular changes that may lead to cancer. HSIL is most frequently diagnosed in women in their forties.
A less common type is differentiated VIN (dVIN), representing about 5% of cases. Unlike HSIL, dVIN is not linked to HPV infection but is associated with chronic inflammatory skin conditions of the vulva, like lichen sclerosus. Differentiated VIN is more common in women over 60.
A primary cause for HSIL is a long-term HPV infection the body fails to clear. Other risk factors include smoking and a compromised immune system, from medications or an infection like HIV, which can hinder the body’s ability to fight the HPV infection.
Symptoms and Diagnosis
The signs of VIN can vary, and some individuals may experience no symptoms. The most common is persistent itching (pruritus). Other symptoms can include soreness, burning, or tingling in the vulvar area, which may worsen during urination.
Visible skin alterations are another sign, such as thickened patches of skin or areas that appear white, red, pink, or dark brown. Lesions may be raised, flat, or have a warty appearance, and pain during sexual intercourse is also possible.
Diagnosis begins with a physical examination of the vulva. A provider may use a colposcope, a magnifying instrument, for a more detailed view of the skin. To confirm the diagnosis, a biopsy is performed, which involves taking a small tissue sample for laboratory examination.
Treatment Approaches
The choice of treatment for VIN depends on the type, size, and location of the abnormal area, and the patient’s health. One common treatment is surgical removal of the affected tissue. This procedure, called a wide local excision, involves cutting out the lesion with a small margin of healthy skin to ensure all abnormal cells are removed.
Ablative therapies are another option, using energy to destroy abnormal cells on the skin’s surface. Laser ablation uses a focused beam of light to vaporize the precancerous cells, while diathermy uses a small electrical current to achieve the same result.
For some cases of multifocal HSIL, topical medical therapy is a non-surgical alternative. A cream containing the drug imiquimod can be applied to the skin to stimulate the local immune system to attack the abnormal cells. Steroid creams may also be used to reduce inflammation and manage itching.
Prognosis and Follow-Up Care
With proper treatment, the outlook for individuals with VIN is excellent. Treatment is highly effective at removing the precancerous cells, but it does not eliminate the underlying risk factors, meaning the condition can return. The possibility of recurrence makes consistent, long-term follow-up care an important part of the management plan.
Even after successful treatment, VIN can reappear in the same area or a different part of the vulva. Follow-up care involves regular check-ups with a specialist to monitor the vulvar skin for any new changes or signs of recurrence. This ongoing vigilance ensures that any new lesions can be addressed promptly, maintaining a positive long-term prognosis.