Malignant mixed Mullerian tumour of uterus secondary to tamoxifen therapy for hormone responsive breast cancer

Abstract

Tamoxifen is used in the treatment of hormone responsive breast cancer because of its antiestrogenic effect. However, it also has an estrogenic effect on the uterus, thereby increasing the risk of endometrial hyperplasia, endometrial polyp and endometrial neoplasms such as endometrial adenocarcinoma and malignant mixed Mullerian tumour (MMMT). This case describes the possible pathogenesis and risk of developing MMMT due to long-term tamoxifen intake in hormone responsive breast cancer.