Stromal sarcoma arising on endometriosis. A clinicopathological and immunohistochemical study of 4 cases

The development of stromal sarcomas on the foci of endometriosis is extreme ly rare and the differential diagnosis from other tumors of myogenic, vascu lar, hemopoietic or epithelial origin may present great diagnostic difficul ties. We investigated the clinicopathological and immunohistochemical chara cteristics of 4 cases of endometrial stromal sarcoma. th:lt developed on en dometriotic foci of the uterus, vagina and omentum. Thye were classed as hi gh grade (1/4) or low grade (3/4) malignant potential tumors, according to their mitotic activity. Immunohistochemically these tumors gave a positive reaction to vimentin, but were negative to desmin, smooth muscle actin, fac tor VIII, EMA and LCA. These characteristics permit their identification an d a proper therapeutic approach.