Types of Uterine Cancer: Common, Rare and More Varieties

Uterine cancer types

Uterine cancer has two primary types that develop in different parts of the uterus:

Endometrial cancer develops in the lining of the uterus, called the endometrium. This is the most common type of uterine cancer, accounting for more than 90 percent of cases.

Uterine sarcoma is a rarer type of uterine cancer, and forms in the muscles or other tissues of the uterus.

Cervical cancer develops in the lower part of the uterus, the cervix, and is not a type of uterine cancer.

Endometrial cancer

Endometrial cancer is the most common form of uterine cancer. Because the endometrium is part of the uterus, endometrial cancer is often referred to as uterine cancer. Endometrial cancer is the most commonly diagnosed gynecologic cancer (which includes cancers of the uterus, cervix, ovaries, vulva, vagina and fallopian tubes).

Endometrial cancer forms when cells in the inner lining of the uterus (endometrium) begin to grow out of control. This cancer type is divided into various subtypes based on how the cells look under a microscope:

Endometroid adenocarcinoma, which accounts for most cases of endometrial cancer
Serous adenocarcinoma, which are tumors that are more likely to spread to the lymph nodes and other parts of the body
Adenosquamous carcinoma, a rare uterine cancer that is similar to adenocarcinoma and carcinoma of the squamous cells that line the outer layer of the uterus
Uterine carcinosarcoma, which has cancer cells that look like endometrial cancer and sarcoma and has a high risk of spreading to the lymph nodes and other parts of the body

Uterine cancer

Uterine sarcomas, which form in the muscle wall of the uterus, are rare, making up less than 4 percent of all cancers of the uterus. Each subtype of uterine sarcoma differs in the way it develops and changes over time, as well as in how it is treated. The three main types of uterine sarcoma are:

Uterine leiomyosarcoma: The most common type of uterine sarcoma, this disease forms in the muscular wall of the uterus, known as the myometrium, and it makes up about 2 percent of uterine cancers.

Endometrial stromal sarcomas: These tumors develop in the connective tissue that supports the endometrium. These cancers represent less than 1 percent of all uterine cancers, and typically grow slowly.

Undifferentiated sarcoma: A rare subtype, this cancer is similar to endometrial stromal sarcoma, but it is more aggressive, meaning it grows and spreads more quickly. These cancers make up less than 1 percent of all uterine cancers.