What condition is often characterized by the presence of endometrial tissue outside the uterus?

The condition characterized by the presence of endometrial tissue outside the uterus is endometriosis. This is a complex condition where tissue similar to the lining of the uterus grows in other areas such as the ovaries, fallopian tubes, and the pelvic cavity. The ectopic endometrial tissue continues to act as it would inside the uterus, thickening and shedding during the menstrual cycle, which can lead to significant pain and often results in inflammation and the formation of scar tissue.

Understanding this condition is crucial in women's health, as it can affect fertility and quality of life. Symptoms may include chronic pelvic pain, painful periods, pain during intercourse, and other related issues. Diagnosis typically involves imaging studies and sometimes laparoscopy, while treatment options may range from pain management to hormonal therapies or surgical interventions.

The other conditions listed—ovarian cysts, uterine fibroids, and polycystic ovary syndrome (PCOS)—do not specifically involve the growth of endometrial tissue outside the uterus. Ovarian cysts are fluid-filled sacs on the ovary, uterine fibroids are benign tumors of the uterine muscle, and PCOS is a hormonal disorder characterized by irregular periods, excess androgen levels, and polycyst