Ovarian cyst torsion and extreme ovarian stimulation in a premenopausal patient treated with tamoxifen for ductal carcinoma in situ of the breast.

Tamoxifen is increasingly used in adjuvant endocrine therapy for postsurgery breast cancer patients and in chemoprevention for high-risk patients. We present a case of bilateral ovarian cyst development with consecutive unilateral cyst torsion and elevated serum estradiol in a premenopausal patient treated with tamoxifen after breast-conserving surgery.