[Carcinosarcomas (malignant mixed Mullerian tumors) of the uterus. Morphology, pathogenetic aspects and prognostic factors].

Malignant mixed Mullerian tumors (MMMT; carcinosarcomas) are rare epithelial-mesenchymal tumors. With an overall survival rate of 30%-40% the prognosis is much worse compared to high grade endometrioid or serous/clear cell carcinomas. Depending on the histology of the mensenchymal components a distinction is made between homologous and heterologous MMMT. Clinical, morphologic and molecular data suggest that MMMTs are really metaplastic carcinomas in which the mesenchymal part retains epithelial features. The strongest prognostic factor is tumor stage followed by lymph node metastases, deep myometrial infiltration, involvement of the cervix and tumor size. The distinction between homologous and heterologous MMMT is prognostically insignificant. Due to unreliable clinical staging and a high rate of occult lymph node metastases, the pathological-anatomical work-up is of great importance. Clinical and pathologic staging should be performed as in endometrial carcinoma. The main differential diagnoses include uterine sarcomas, adenosarcoma and benign metaplastic change within the endometrium.