What condition is characterized by the presence of tissue similar to the lining of the uterus outside the uterus itself?

Endometriosis is characterized by the presence of endometrial-like tissue outside the uterus. This condition occurs when the cells similar to the endometrial lining begin to grow in other parts of the body, such as the ovaries, fallopian tubes, and the pelvic cavity. This ectopic endometrial tissue continues to act as it would within the uterine lining, thickening and shedding during the menstrual cycle. However, since it is located outside the uterus, the tissue cannot exit the body as menstrual flow. This can lead to significant pain, inflammation, and the formation of adhesions, potentially affecting fertility and overall health.

In contrast to other conditions listed, such as fibroids, which are benign tumors of the uterine muscle, polycystic ovary syndrome, which involves hormonal imbalance affecting ovulation, and ovarian cancer, which involves malignant tumors in the ovaries, endometriosis specifically addresses the migration of uterine-like tissue beyond its normal location, making it a distinctive and recognizable condition.