To help you understand what happens when you have cancer, it helps to understand how your body works normally. Your body is made up of tiny building blocks called cells. Normal cells grow and multiply when your body needs them, and die out when your body does not need them any longer.
Cancer is made up of abnormal cells that grow, whether or not your body needs them. In most cancers, the abnormal cells grow to form a lump or mass called a tumor.
Vaginal cancer starts in the cells of your vagina, also known as the birth canal. The vagina is a hollow, tube-like passageway between the bottom part of your uterus and the outside of your body.
Most vaginal cancers begin in the lining of your vagina, the epithelium. These are called vaginal squamous cell carcinomas. This type of vaginal cancer develops over many years. It develops from precancerous changes, called vaginal intraepithelial neoplasia (VAIN).
These are other, very rare types of vaginal cancer:
Adenocarcinomas, which develop in the glands of your vagina
Malignant melanomas, a form of skin cancer, which affect the lower or outer portion of your vagina
Sarcomas, which develop deep in the muscular wall of your vagina