Vulval intraepithelial neoplasia (VIN)

The vulva is the outer part of the female genital area. VIN means that the surface skin cells show abnormal changes confined to the top layer, without invading deeper. Current terminology calls the HPV-related form a high-grade squamous intraepithelial lesion (HSIL) of the vulva and the other form differentiated VIN (dVIN).

The two types behave differently. HSIL tends to affect younger people and can be multifocal, appearing in several places. Differentiated VIN is much less common but is considered to have a higher chance of turning into invasive cancer more quickly, which is why it is taken seriously even when it looks minor.

Macmillan identifies infection with human papillomavirus as the main cause of HSIL. Smoking raises risk by weakening the immune response, and a weakened immune system from HIV, transplant medication or other causes also increases susceptibility. Cancer Research UK adds that having had cervical cancer or cervical cell changes raises vulval risk because of shared HPV exposure.

For differentiated VIN, the main risk factor is a long-standing vulval skin condition. Cancer Research UK describes lichen sclerosus, a chronic condition seen especially in women over 60, as something that may develop into differentiated VIN. Most people with lichen sclerosus never develop VIN or cancer, but regular review is advised.

Many people have no symptoms and VIN is discovered during an examination or biopsy for another reason. If symptoms occur, they commonly include:

• Itching or soreness of the vulva that does not settle

• Burning or tingling, including when passing urine

• Pain during sex

• Thickened, raised patches that may be red, white, grey or darker than the surrounding skin

• A warty look to an area of skin

A GP who finds an unusual area, or who has been treating persistent itch with creams that fail, refers to a gynaecology clinic, often with a suspected cancer pathway if a lump, ulcer or bleeding is present. Specialists use a magnifying instrument to inspect the vulva (vulvoscopy), and take a small skin biopsy under local anaesthetic.

The biopsy tells HSIL from differentiated VIN and rules out invasive cancer. Because HPV is often involved, the cervix and sometimes the vagina and anus are checked, and cervical screening is kept up to date.

Cancer Research UK describes wide local excision as the commonest operation: the abnormal skin is removed with a margin of healthy skin around it. A skinning vulvectomy removes the surface skin over a larger area while keeping the tissue beneath, and reconstruction with a flap or graft may be used. Dissolving stitches are typical, a dressing is usually not needed (a sanitary pad is used instead), and some people go home the same day.

Other approaches in Macmillan information include laser or diathermy ablation, and imiquimod cream, a topical immune-modulating treatment. Which option suits depends on the area involved, the symptoms and the risk of cancer. Differentiated VIN is generally excised rather than treated with cream.

Macmillan notes that VIN frequently recurs and needs long-term monitoring. Reviews are usually every few months at first and then less often, and any new lump, sore, bleeding or change in a patch should be reported promptly rather than waiting for the next appointment.

The area is sensitive and treatment can affect comfort, appearance and sex life. Most hospitals provide a clinical nurse specialist, and Cancer Research UK encourages asking for support. Stopping smoking, treating lichen sclerosus as advised and using emollients and steroid ointment correctly are practical steps within your control.