Types Definition of endometrial cancer: Cancer that forms in the tissue lining the uterus (the small, hollow, pear-shaped organ in a woman's pelvis in which a baby grows). Most endometrial cancers are adenocarcinomas (cancers that begin in cells that make and release mucus and other fluids). 
Estimated new cases and deaths from endometrial (uterine corpus) cancer in the United States in 2008:
- New cases: 40,100
- Deaths: 7,470