What is uterine sarcoma?

Uterine sarcoma occurs when abnormal cells in the muscles and supporting structures of the uterus grow in an uncontrolled way. 

A sarcoma is a cancer of the bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Uterine sarcoma is a rare type of cancer that forms in the muscle or other tissues of the uterus (womb). It usually occurs after menopause. 

Uterine sarcoma is different from endometrial cancer, a disease in which cancer cells start growing inside the lining of the uterus (endometrium). Uterine sarcoma is less common than endometrial cancer.  

However, some sources refer to endometrial cancer as uterine cancer, and vice versa. If you have been told you have ‘cancer of the uterus’, ‘cancer of the womb’ or ‘uterine cancer’, and you are not sure if it is endometrial cancer or uterine sarcoma, check with your doctor. 

About the uterus

The uterus, or womb, is the main female reproductive organ. It is about the size and shape of a hollow, upside-down pear, and sits low in the abdomen between the bladder and rectum. It is joined to the vagina by the cervix, which is the neck of the uterus. 

The bulk of the uterus is smooth muscle tissue, which is called the myometrium. The lining of the uterus is called the endometrium. 

When women ovulate (produce eggs in their ovaries), an egg travels through the fallopian tube into the uterus. If the egg is fertilised by a sperm, it will implant itself into the endometrium and grow into a foetus. 

If the egg is not fertilised, the top layers of the endometrium are shed and flow out of the body through the vagina during menstruation. This is known as your period. 

Menopause occurs when a woman no longer releases the hormones that cause ovulation and menstruation. A menopausal woman’s monthly periods stop, and she can no longer become pregnant. The uterus becomes smaller and the endometrium becomes thinner.