Clinicopathologic correlation of endometrial stromal sarcomas: a retrospective study of 42 cases

Endometrial stromal sarcoma (ESS) is a rare mesenchymal tumor, which accounts for less than 1% of all uterine malignancies, but it is the second most common uterine malignant mesenchymal tumor, and divided into low-grade ESS (LGESS), high-grade ESS (HGESS) and undifferentiated uterine sarcoma (UUS) according to the WHO Classification of Tumors of Female Reproductive Organs [2014] (1). LGESS is typically composed of cytologically bland fusiform cells resembling stromal cells of proliferative-phase endometrium, permeating the myometrium as well as the intramyometrial or parametrial vessels (2,3). Both HGESS and UUS often exhibit myometrial invasion, hemorrhage and necrosis, as well as marked nuclear pleomorphism with high mitotic activity (2,3). And UUS is a highly malignant sarcoma, which lacks endometrial stromal differentiation and exhibits a complex karyotype with no specific translocation (1)