Morphologic prognostic factors of malignant mixed müllerian tumor of the uterus: a clinicopathologic study of 58 cases.

Sixty-one patients with malignant mixed müllerian tumor (MMMT) of the uterus were seen at L'Hôtel-Dieu de Québec between 1950 and 1986, and the histopathologic material was available for review in 58 cases. Of the morphologic parameters studied, the histologic grade of both epithelial and mesenchymal components correlated with the initial stage. Patients with stages I and II disease had a significantly better survival rate than those with stages III and IV (P less than 0.006). Twenty-five patients with a minimum follow-up of two years were initially stage I or II. All six patients of this subgroup with an epithelial component of serous carcinoma type were dead of their disease at 2 yr. Although not statistically significant, tumor necrosis, the mode of tumor invasive (pushing and infiltrative), and the ratio of epithelial to mesenchymal components tended to influence the outcome. The mitotic rate, the type of mesenchymal components, and vascular and myometrial invasion were of no prognostic significance. We conclude that the outcome of patients with uterine MMMT is mainly influenced by the initial stage and the type of epithelial component. The influence of tumor necrosis, the ratio of epithelial to mesenchymal component, and the mode of tumor invasion deserve further studies.