Cancerous tumours of the vulva

A cancerous tumour of the vulva can grow into nearby tissue and destroy it. The tumour can also spread (metastasize) to other parts of the body. Cancerous tumours are also called malignant tumours. There are several types of vulvar cancer.

Squamous cell carcinoma (SCC) is the most common malignant tumour of the vulva. Up to 90% of vulvar cancers are SCC.

SCC begins in the main type of skin cells called squamous cells. These cells are flat and thin. SCC of the vulva is most often found on the labia majora and minora. It can develop from a precancerous condition called vulvar intraepithelial neoplasia (VIN).

SCC of the vulva is described as human papillomavirus (HPV)-associated or HPV-independent based on whether it is linked to HPV infections.

SCC can also be grouped by how it looks under a microscope (called histologic subtypes).

Keratinizing SCC is the most common. It occurs most often after menopause. It isn’t related to HPV infections. This subtype of SCC often develops from HPV-independent VIN.

Basaloid and warty SCC are less common. They usually occur at a younger age and are linked with HPV infections, especially types 16, 18, 31 and 33. These subtypes of SCC usually develop from a type of HPV-associated VIN called high-grade squamous intraepithelial lesion (HSIL).

Verrucous carcinoma is very rare. It grows slowly and has a distinct appearance that looks like a large wart. This type of SCC is usually not related to HPV.

Vulvar melanoma is the second most common type of vulvar cancer. Melanoma is a type of skin cancer that begins in the cells of the skin that produce pigment (melanocytes). It most often develops in areas of the skin that are exposed to the sun. But it may also develop in other areas such as the vulva.

Vulvar melanoma is most often found on the labia minora or clitoris. But it can also be found in other parts of the vulva. It may look like a dark area of skin or may start in an existing mole. It usually occurs after menopause.

Paget disease of the vulva is a rare type of adenocarcinoma that starts in the gland cells of the vulvar skin. It often appears as a red, weeping rash.

Sometimes Paget disease of the vulva is linked to an adenocarcinoma in a Bartholin gland, a sweat gland or nearby tissues of the vagina, cervix, urethra, bladder or rectum. It can also be linked to breast cancer. Because of this possible connection, people with Paget disease of the vulva usually need to have different screening tests, such as a colonoscopy and mammography, to check for other cancers.

Paget disease of the vulva usually occurs after menopause.

There are other rarer types of vulvar cancer:

• Basal cell carcinoma is found in the basal cells (the deepest layer of skin cells).
• Bartholin gland carcinoma develops in the Bartholin’s glands at the vaginal opening.

• Sarcoma is found in soft tissue cells. Sarcoma of the vulva includes leiomyosarcoma, rhabdomyosarcomas, angiosarcomas and malignant fibrous histiocytoma.