Endometriosis is defined as presence of endometrial glands and stroma outside endomoetrium [1]. Ovarian endometriomas are a common presentation of endometriosis. Surgery is universally considered the first therapeutic approach for women with symptomatic or enlarging endometriomas [2,3] but it may have side effect on ovarian reserve. Dienogest (DNG) is an orally-active semisynthetic, steroidal progestogen, highly selective for progesterone receptors, derivative of 19-nortestosterone, that has recently been introduced for the treatment of endometriosis. Clinical studies of DNG with durations between 12 and 24 weeks have provided information on optimal dosing and on efficacy and safety characteristics that are relevant to the long-term management of endometriosis [4-6]. However, there are few studies that show a long term treatment over 53 weeks [7]. An over 90 weeks treatment with DNG 2mg per day in our case report resulted in a remarkable regression of endometrioma and elimination of symptoms.

Endometriosis is defined as presence of endometrial glands and stroma outside endomoetrium [1]. Ovarian endometriomas are a common presentation of endometriosis. Surgery is universally considered the first therapeutic approach for women with symptomatic or enlarging endometriomas [2,3] but it may have side effect on ovarian reserve. Dienogest (DNG) is an orally-active semisynthetic, steroidal progestogen, highly selective for progesterone receptors, derivative of 19-nortestosterone, that has recently been introduced for the treatment of endometriosis. Clinical studies of DNG with durations between 12 and 24 weeks have provided information on optimal dosing and on efficacy and safety characteristics that are relevant to the long-term management of endometriosis [4-6]. However, there are few studies that show a long term treatment over 53 weeks [7]. An over 90 weeks treatment with DNG 2mg per day in our case report resulted in a remarkable regression of endometrioma and elimination of symptoms.