Endometriosis means that the endometrial tissue, which normally lines the uterus, grows in other locations. It can grow on the ovaries, inside the muscular layer of the uterus, or in the pelvic cavity. The ectopic endometrial tissue responds to changes in the body's estrogen levels during each menstrual cycle, creating symptoms similar to menstrual bleeding. If it grows on the ovaries, it may form a "chocolate cyst" on the ovaries that gradually enlarges with each menstrual cycle. If it grows within the muscular layer of the uterus, it can lead to adenomyosis, causing significant pain during menstruation. If it grows in the pelvic cavity, it can lead to the formation of pelvic lesions. Therefore, it is recommended that patients with such conditions seek prompt medical treatment.