Endometrioid adenocarcinoma after insertion of a levonorgestrel-releasing intrauterine system

The levonorgestrel-releasing intrauterine system (IUS) is now widely used and recommended as a reliable contraceptive and treatment for menorrhagia. It also potentially provides a simple alternative to treatment for women with stage-1, grade-1 endometrial cancers who are at high risk for surgery. This case describes a 39-year-old multiparous patient who visited the gynecology outpatient department at a district general hospital with a history of heavy, prolonged periods for 1 year. Hysteroscopy and biopsy specimen revealed benign nonsecretory endometrium and a levonorgestrel-releasing IUS was inserted. The patient visited again 4 years later with an 8-month history of prolonged bleeding. Endometrial biopsy specimen confirmed well-differentiated endometrioid adenocarcinoma. This is the first case report, to our knowledge, where hysteroscopy was performed before levonorgestrel-releasing IUS insertion with conclusive evidence of initial negative malignancy followed by development of endometrial cancer 4 years after insertion. This case raises the question of the safety of levonorgestrel-releasing IUS for the prevention and treatment of endometrial hyperplasia and carcinoma.