Endometrium is the lining of the inside of the womb (uterus). Overgrowth of this lining can create polyps. Polyps are fingerlike growths that attach to the wall of the uterus. They can be as small as a sesame seed or larger than a golf ball. There may be just one or many polyps.
No one knows exactly why some women get endometrial polyps. They tend to grow when there is more of the hormone estrogen in the body.
Most endometrial polyps are not cancerous. About 5% can be cancerous or precancerous. The chance of cancer is higher if you are postmenopausal, on Tamoxifen, or have heavy or irregular periods.
These factors may increase the risk for endometrial polyps:
- Tamoxifen, a treatment for breast cancer
- Postmenopausal hormone replacement therapy
- Family history of Lynch syndrome or Cowden syndrome (genetic conditions that run in families)