The most common cancer of the uterus starts in the internal lining of the uterus and is called endometrial cancer.  A  sarcoma is a less common malignancy of the uterus, which can arise from either from the cells supporting the endometrium or from the muscle part of the uterus, called the myometrium.  

Endometrial cancer usually starts as a benign overgrowth of the lining, called hyperplasia, and usually takes many years to develop.  There is a rare subtype of endometrial cancer, called uterine papillary serous carcinoma (UPSC), which can be much more aggressive and grows faster, skipping the precancerous overgrowth or hyperplasia. Although endometrial cancer can occur at any age, it is rare before 35 years of age and most often is found after menopause. 

It is important to review the anatomy to understand the recommended treatment, which usually starts with surgery.  If it is found only in the uterus, and has not spread, surgery is often the only treatment required.   Once cancer of the uterus has spread, radiation and/or chemotherapy is also needed. 

Sarcoma of the uterus is usually more aggressive and can spread earlier. However, there are sarcoma  subtypes that can be easier to cure.

This cartoon image shows the uterus and attached female anatomy structures.  It lies in the middle of the pelvis.  The lowest part of the uterus is called the cervix, which can be seen by your doctor at the time of a pelvic exam and Pap smear test. The reddish pink part of the uterus is the myometrium and the internal white lining is the endometrium.