Case of accessory ovary in the round ligament with associated endometriosis.

The phenomenon of accessory ovary, initially described in 1864, is extremely rare. We report a case of an accessory ovary in a round ligament with endometriosis. At the time of laparoscopy a firm 2- to 3-cm mass was noted within the round ligament with a normal ovary visualized. Dissection and removal of the mass was performed. Histopathology revealed ovarian stroma and dense connective tissue with endometriosis. This case fulfills the criteria established in 1959 for accessory ovary and is the first case of an accessory ovary reported within the round ligament. A unique finding with the accessory ovary in this case is the presence of endometriosis. No reported cases exist of endometriosis within an accessory ovary. This information may be pertinent for evaluation of dysmenorrhea when no endometrial implants are present, or with the persistence or recurrence of endometriosis and pain after a bilateral salpingo-oophorectomy.