<prompt> The commonest site of endometriosisVaginaOvaryUrinary bladderPeritoneal cavity  <response>: EndometriosisEndometriosis ectopic endometrium is the term used to describe the presence of endometrium endometrial glands or stroma in abnormal locations outside the uterus.It occurs in following sites, in decreasing order of frequency -1. Ovary 2. Uterine ligaments 3. Rectovaginal septum 4. Pelvic peritoneum5. Laprotomy scar 6. Umbilicus, vagina, vulva or appendix.Adenomyosis is the presence of endometrial tissue in the uterine wall, i.e., in the myometrium. 