Types

Most uterine Cancers are put into categories, based on the type of cell they start in:

These tumors start in the muscular wall of the uterus (the myometrium). They are by far the most common type. These tumors can grow and spread quickly.

ESS tumors start in the supporting connective tissue (stroma) of the lining of the uterus (the endometrium). These cancers are rare.
If the tumor is low grade, the cancer cells do not look very different from normal cells and the tumor tends to grow slowly. Women with low-grade ESS have a better outlook (prognosis) than women with other kinds of uterine Cancers.
High-grade ESS means the cancer cells look very different from normal cells, and the tumor is growing quickly. This type of ESS is most often found when the tumor is already large and/or has spread. These tumors are hard to treat.

These cancers may start in the endometrium or the myometrium. They grow and spread quickly and tend to have a poor outlook.

Several types of benign (not cancer) tumors can also develop in the connective tissues of the uterus. These tumors, such as Leiomyomas, Adenofibromas, and Adenomyomas are also known as types of fibroid tumors. Most of the time, these tumors don't need to be treated. But treatment may be needed if they start causing problems, like pelvic pain, heavy bleeding, frequent urination, or constipation. In some cases, the tumor is removed, leaving the rest of the uterus in place. This surgery is called a myomectomy. Some treatments destroy these benign tumors without surgery, by blocking the blood vessels that feed them, by killing the tumor cells with electric current, or by freezing them with liquid nitrogen. Another option is to remove the entire uterus. This surgery is called a hysterectomy.