Endometriosis is a non-neoplastic condition where functional ectopic endometrial tissue grows outside the uterus, influenced by ovarian hormones before menopause. Common sites include ovaries, pelvic cavity, uterine ligaments, tubes, and rectovaginal septum. Symptoms include infertility, pelvic pain, dysmenorrhea, dyspareunia, and dysuria. Microscopically, lesions appear as reddish-blue or yellowish-brown nodules up to 2 cm containing endometrial glands and stroma. Theories for its pathogenesis include retrograde menstruation, metaplasia of coelomic epithelium, and lymphatic or vascular spread from the uterus