An unusual theca lutein cyst. Report of a case

An unusual cyst lined by spontaneously lutenized theca cells--which appears to be the first reported in an adult female--is presented. It is postulated that its formation was due to an abnormal end-organ response and that the progesterone produced by it caused amenorrhea. It is suggested that theca lutein cysts may have two origins--an increased quantity of chorionic gonadotropin or end-organ hypersensitivity. When a unilateral, unilocular theca lutein cyst is found, the presence of associated trophoblastic disease can be ruled out.