Metastatic breast ductal carcinoma detected in a toremifene-associated endometrial polyp: case report and literature review

Uterine metastases are rare events, but when they occur, the first extragenital neoplasm responsible is breast carcinoma. Toremifene, used in breast cancer hormonotherapy, has a partial estrogenic agonist effect in the endometrium, responsible for potential abnormalities, like polyps. A 53-year-old woman, receiving toremifene due to previously excised breast ductal carcinoma, presented with endometrial thickness during an abdominopelvic ultrasound follow-up. Hysteroscopy revealed an endometrial polyp, which was removed. Microscopic examination showed infiltration by a malignant ductal pattern neoplasm, with signet ring cells. The patient underwent hysterectomy and bilateral salpingo-oophorectomy. The final pathological diagnosis was metastatic breast carcinoma to the endometrium and cervix. This is the first reported case of breast metastases detected in a toremifene-associated endometrial polyp.