De novo postmenopausal endometriosis during tibolone treatment: a case report and review of the literature

Endometriosis is uncommon before puberty and after menopause as it is an estrogen-dependent disease. A case is presented of postmenopausal endometriosis encountered in a patient who had received tibolone (Livial, Organon, Cambridge, UK) 1 year before the diagnosis of the adnexal mass for 3 months for relief from vasomotor symptoms and had the medication stopped because of fibrocystic disease of the breast. Transvaginal ultrasonography showed homogeneous cystic adnexal mass of 36 × 26 mm with no internal echoes in the right ovary. Laparoscopic right salpingooophorectomy was performed and the histopathological examination of the cyst showed an endometriotic cyst. Most of the cases with postmenopausal endometriosis are associated with the use of hormone replacement therapy (HRT). However, tibolone is recommended in hormone replacement therapy of postmenopausal symptomatic women who have a past history of hormone-dependent tumors such as endometriosis. There is restricted data in the literature about tibolone use and recurrence or de novo formation of endometriosis.