The vagina is a 3 to 4 inch (7 1/2 to 10 cm) tube. It is sometimes called the birth canal. The vagina goes from the cervix (the lower part of the uterus) to open up at the vulva (the external genitals). The vagina is lined by a layer of flat cells called squamous cells. This layer of cells is also called epithelium (or epithelial lining) because it is formed by epithelial cells.

The vaginal wall underneath the epithelium contains connective tissue, muscle tissue, lymph vessels, and nerves. The vagina is usually in a collapsed state with its walls touching each other. The vaginal walls have many folds that help the vagina to open and expand during sexual intercourse or the birth of a baby. Glands near the opening of the vagina secrete mucus to keep the vaginal lining moist.

Types of vaginal cancer

There are several types of vaginal cancer.

Squamous cell carcinoma

About 70% of vaginal cancers are squamous cell carcinomas. These cancers begin in the squamous cells that make up the epithelial lining of the vagina. These cancers are more common in the upper area of the vagina near the cervix. Squamous cell cancers of the vagina are often slow to develop. First, some of the normal cells of the vagina acquire pre-cancerous changes. Then some of the pre-cancer cells turn into cancer cells. This process can take many years.

The medical term most often used for this pre-cancerous condition is vaginal intraepithelial neoplasia (VAIN). "Intraepithelial" means that the abnormal cells are only found in the surface layer of the vaginal skin (epithelium). VAIN is often divided into 3 categories -- VAIN1, VAIN2, and VAIN3, with higher numbers indicating furthest progression toward a true cancer. VAIN is more common in women who have had their uterus removed (hysterectomy) and in those who were previously treated for cervical cancer or pre-cancer.

In the past, the term dysplasia had been used instead of VAIN. This term is used much less now. When talking about dysplasia, there is also a range of increasing progress toward cancer - first, mild dysplasia; next, moderate dysplasia; and then severe dysplasia.

Adenocarcinoma

Cancer that begins in gland cells is called adenocarcinoma. This type of cancer makes up about 15% of vaginal cancers. The usual type of vaginal adenocarcinoma typically develops in women older than 50. One certain type, called clear cell adenocarcinoma, occurs more often in young women who were exposed to diethylstilbestrol (DES) in utero (when they were in their mother’s womb). (See the section "What are the risk factors for vaginal cancer?" for more information on DES and clear cell carcinoma.)

Malignant melanoma

Melanoma is a cancer that develops from pigment-producing cells called melanocytes. These cancers usually are found on sun-exposed areas of the skin but can form on the vagina or other internal organs. They account for about 9% of all vaginal cancers. Melanoma tends to affect the lower or outer portion of the vagina. The tumors vary greatly in size, color, and growth pattern.

Sarcoma

A sarcoma is a cancer that begins in the cells of bones, muscles, or connective tissue. Up to 4% of vaginal cancers are sarcomas. These cancers form deep in the wall of the vagina, not on its surface. There are several types of vaginal sarcomas. Rhabdomyosarcoma is the most common type of vaginal sarcoma. It is most often found in children and is rare in adults. A sarcoma called leiomyosarcoma is seen more often in adults. It tends to occur in women older than 50.

Other cancers

Cancers of the vagina are much less common than cancers that start in other organs (such as the cervix, uterus, rectum, or bladder) and then spread to the vagina. These cancers are named after the place where they started. Also, a cancer that involves both the cervix and vagina is considered a cervical cancer. Likewise, if the cancer involves both the vulva and the vagina, it is considered a vulvar cancer. This document refers only to cancers that start in the vagina, also known as primary vaginal cancers.

Last Medical Review: 12/30/2008
Last Revised: 05/14/2009