ENDOMETRIAL CANCER starts in the inner lining of the uterus (womb). This lining is called the endometrium.
The uterus is a hollow organ, about the size and shape of a medium-sized pear. The uterus is where a fetus grows when a woman is pregnant. It has 2 main parts. The lower part, which extends into the vagina, is called the cervix. The upper part is the body of the uterus (also called the corpus). The body of the uterus has 2 layers. The inner layer is the endometrium. The outer layer of muscle is known as the myometrium. This thick layer of muscle is needed to push the baby out during birth.
Nearly all cancers of the uterus start in the endometrium. They are called endometrial carcinomas. Cancers can also start in the muscle layer of the uterus. These cancers belong to the group of cancers called sarcomas.