What is uterine carcinosarcoma

Malignant mesodermal mixed tumor of the uterus originates from the most poorly differentiated endometrial stromal tissue among the derivatives of the Müllerian duct. It can differentiate into myxoid tissue, connective tissue, cartilage tissue, striated muscle tissue, and smooth muscle tissue. It can contain both malignant epithelial and stromal components, i.e., cancer and sarcoma components. If both sarcoma and cancer components are derived from the original tissue components of the uterus, it is a homologous malignant Müllerian mixed tumor; if the sarcoma contains tissue components other than the uterus, such as striated muscle, cartilage, bone, etc., it is a heterologous malignant Müllerian mixed tumor.

There are many names for this tumor. In the past, carcinosarcoma was often used to refer to sarcomas with homologous mesenchymal tissue as the component. Malignant mesodermal mixed tumor was also used to refer to sarcomas with heterologous mesenchymal tissue as the component. Some scholars also use the name of carcinosarcoma to refer to all malignant mixed Mullerian tumors, which is not very accurate. The word carcinosarcoma does not mean homologous sarcomas alone. Even if it contains heterologous sarcoma components, it can still be called carcinosarcoma.

In addition, carcinosarcoma can also occur in other tissues of the body. Therefore, "carcinosarcoma" does not mean a malignant tumor originating from the Müllerian duct. As for "malignant mesodermal mixed tumor", although it contains the meaning of heterologous components of mesodermal tissue, it can also contain homologous components. Therefore, it is more appropriate to call this type of Müllerian duct-derived tumor with a mixture of malignant epithelial components and mesenchymal components malignant Müllerian mixed tumor. According to the sarcoma components, it is further divided into two subtypes: homologous and heterologous.