The histologic appearances are interlacing bundles of smooth muscle cells with variable uniformity. In some tumors, the cells are well differentiated and resemble leiomyoma. In others, the tumor cells are more anaplastic, with atypical nuclei and multinucleated cells, and numerous mitoses. Note mitotic figures and large nuclear size. This shows more cellular pleomorphism with some multinucleated cells.
Younger patients have more favorable outcome.
This is a malignant tumor in which the epithelial and stromal components are both highly malignant. These tumors are derived from multipotential stromal cells. If they contain mesynchymal components such as skeletal muscle, bone, cartilage or fat, which are foreign to the uterus, they are classified as heterologous. If endometrial stromal components are present without other elements, the tumor is termed homologous. The tumors present as large, polypoid mass that usually fills the endometrial cavity and may protrude through the external os, in an elderly woman.