Uterine malignant mixed Müllerian tumor after adjuvant tamoxifen treatment for breast cancer.

BACKGROUND: Uterine malignant mixed Müllerian tumor (MMMT), also known as carcinosarcoma, is a biphasic tumor of the female genital tract and demonstrates both malignant epithelial (carcinoma) and mesenchymal (sarcoma) components. The authors present two cases of uterine MMMT after adjuvant tamoxifen (TAM) treatment for breast cancer and a review of the current literature. CASES: The patients presented with a complaint of abnormal uterine bleeding. They both had a history of breast cancer Stage IIB previously treated with modified radical mastectomy, at 51 and 78 months, respectively. They also had history of tamoxifen treatment 20 mg daily for seven and 73 months respectively. They underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy and total omentectomy. Histopathology revealed a uterine MMMT. Postoperatively, they received adjuvant chemotherapy and radiotherapy. One of the patients died 26 months after initial surgery due to uterine MMMT. CONCLUSION: Uterine MMMT is a rare, highly-aggressive, and rapidly-progressing tumor associated with a poor prognosis. Postmenopausal patients, with prolonged adjuvant TAM treatment for breast cancer, are at increased risk for the development of uterine MMMT.