Carcinosarcoma is a rare, extremely aggressive tumor of the uterus with a poor prognosis. The authors describe a case of a 78-yearold woman who presented with a giant mass protruding through the cervix, vagina, and vulva.A total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed. The histopathological examination of the surgical specimen revealed a malignant mixed Müllerian tumor. The clinical and pathological features, molecular data, and prognosis of this aggressive neoplasm are discussed. Although uterine carcinosarcomas are extremely rare, when a postmenopausal woman with a vulvar mass is admitted to the gynecology clinic, the physician should consider that the mass may be a carcinosarcoma.