What condition is characterized by the growth of endometrial cells outside the uterus?

Endometriosis is characterized by the presence and growth of endometrial tissue, which normally lines the inside of the uterus, in locations outside of it. This can occur on the ovaries, fallopian tubes, the outer surface of the uterus, and other organs within the pelvic cavity. The ectopic endometrial tissue reacts to hormonal changes in the menstrual cycle, leading to pain, inflammation, and the formation of scar tissue, which can result in complications such as fertility issues.

In contrast, fibroids refer to benign tumors made of muscle and fibrous tissue that grow within the uterus, but they do not specifically relate to endometrial cells. Uterine prolapse involves the descent of the uterus into the vaginal canal due to weakened pelvic support structures and is not associated with growth of endometrial tissue. Pelvic inflammatory disease (PID) is an infection of the reproductive organs that can cause pelvic pain, but it is not characterized by the growth of endometrial cells outside the uterus. Thus, endometriosis is distinct in its definition and implications for women's health.