Role of prolonged stimulation of tamoxifen therapy in the etiology of endometrial sarcomas.

We present the first case of heterologous mixed mesodermal tumor that developed 9 years following tamoxifen therapy in a climacteric woman with no previous pelvic irradiation and was initially treated by total abdominal hysterectomy and bilateral salpingo-oophorectomy. She continued tamoxifen therapy for 2 years, following the initial treatment, until the diagnosis of a recurrent tumor by laparotomy. The patient died of the disease 5 months subsequent to the second surgery. The association of prolonged unopposed estrogenic stimulation, with tamoxifen as a possible etiologic factor in the development of endometrial sarcomas, is discussed.