Uterine sarcoma is a disease in which malignant (cancer) cells form in the muscles of the uterus or other tissues that support the uterus.

The uterus is part of the female reproductive system. The uterus is the hollow, pear-shaped organ in the pelvis, where a fetus grows. The cervix is at the lower, narrow end of the uterus, and leads to the vagina.

Uterine sarcoma is a very rare kind of cancer that forms in the uterine muscles or in tissues that support the uterus. (Information about other types of sarcomas can be found in the PDQ summary on Soft Tissue Sarcoma Treatment.)

Uterine sarcoma is different from endometrial cancer, a disease in which cancer forms in the tissue that lines the uterus. Carcinosarcoma is a subtype of endometrial cancer and is staged using endometrial cancer definitions. (For more information, seeEndometrial Cancer Treatment.)

Uterine sarcomas include leiomyosarcomas, endometrial stromal sarcomas, and adenosarcomas.

Past treatment with radiation therapy to the pelvis can increase the risk of uterine sarcoma.

Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk with your doctor if you think you may be at risk. Risk factors for uterine sarcoma include the following:

• Past treatment with radiation therapy to the pelvis.
• Treatment with tamoxifen for breast cancer. If you are taking this drug, have a pelvic exam every year and report any vaginal bleeding (other than menstrual bleeding) as soon as possible.

Signs of uterine sarcoma include abnormal bleeding.

Abnormal bleeding from the vagina and other signs and symptoms may be caused by uterine sarcoma or by other conditions. Check with your doctor if you have any of the following:

• Bleeding that is not part of menstrual periods.
• Bleeding after menopause.
• A mass in the vagina.
• Pain or a feeling of fullness in the abdomen.
• Frequent urination.

Tests that examine the uterus are used to diagnose uterine sarcoma.

The following tests and procedures may be used:

• Physical exam and health history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
• Pelvic exam: An exam of the vagina, cervix, uterus, fallopian tubes, ovaries, and rectum. A speculum is inserted into the vagina and the doctor or nurse looks at the vagina and cervix for signs of disease. A Pap test of the cervix is usually done. The doctor or nurse also inserts one or two lubricated, gloved fingers of one hand into the vagina and places the other hand over the lower abdomen to feel the size, shape, and position of the uterus and ovaries. The doctor or nurse also inserts a lubricated, gloved finger into the rectum to feel for lumps or abnormal areas.
• Pap test: A procedure to collect cells from the surface of the cervix and vagina. A piece of cotton, a brush, or a small wooden stick is used to gently scrape cells from the cervix and vagina. The cells are viewed under a microscope to find out if they are abnormal. This procedure is also called a Pap smear. Because uterine sarcoma begins inside the uterus, this cancer may not show up on the Pap test.
• Transvaginal ultrasound exam: A procedure used to examine the vagina, uterus, fallopian tubes, and bladder. An ultrasound transducer (probe) is inserted into the vagina and used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. The doctor can identify tumors by looking at the sonogram.
• Dilatation and curettage: A procedure to remove samples of tissue from the inner lining of the uterus. The cervix is dilated and a curette (spoon-shaped instrument) is inserted into the uterus to remove tissue. The tissue samples are checked under a microscope for signs of disease. This procedure is also called a D&C.
• Endometrial biopsy: The removal of tissue from the endometrium (inner lining of the uterus) by inserting a thin, flexible tube through the cervix and into the uterus. The tube is used to gently scrape a small amount of tissue from the endometrium and then remove the tissue samples. A pathologist views the tissue under a microscope to look for cancer cells.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis and treatment options depend on the following:

• The stage of the cancer.
• The type and size of the tumor.
• The patient's general health.
• Whether the cancer has just been diagnosed or has recurred (come back).