What medical condition involves pelvic pain due to endometrial lining present outside the uterus?

The medical condition that involves pelvic pain due to the presence of endometrial tissue outside the uterus is endometriosis. In this condition, the tissue that normally lines the inside of the uterus, called the endometrium, grows outside of it, often on the ovaries, fallopian tubes, and other structures within the pelvis. This misplaced tissue still behaves as it would normally—thickening, breaking down, and bleeding with each menstrual cycle—but because it has no way to exit the body, it can lead to inflammation, scar tissue, and adhesions. Consequently, this can cause significant pelvic pain and discomfort, particularly during menstruation.

Understanding the nature of endometriosis is key to recognizing how it differs from other conditions. For example, fibroids are non-cancerous growths of the uterine muscle and do not involve the displacement of endometrial tissue. Cysts typically refer to fluid-filled sacs that can develop on the ovaries or other organs and are not characterized by endometrial lining. Adenomyosis, while it also involves the endometrial tissue, occurs when this tissue grows into the muscular wall of the uterus itself, rather than outside of it.

In summary, endometriosis is specifically identified by the