Histopathology of Endometrial Stromal Sarcoma with Emphasis on Immunohistochemistry Marker Expression: Report of Three Cases

A BSTRACT Endometrial stromal tumors are rare uterine mesenchymal neoplasms. Endometrial stromal sarcomas (ESSs) are of endometrial stromal origin that accounts for approximately 1% of all uterine malignant neoplasms. ESS is classified into endometrial stromal nodule (ESN), low-grade ESS (LG-ESS), high-grade endometrial stromal sarcoma (HG-ESS), and undifferentiated uterine sarcoma (UUS). The usual clinical presentation of ESS is abnormal uterine bleeding in about 90% of women and uterine enlargement in about 70%, followed by dysmenorrhea and pain in the abdomen in some patients. Clinically, leiomyoma, endometrial polyp, and other malignant entities enter the differential diagnosis. Gross presentation and microscopic examination, along with immunohistochemistry marker expression and clinical correlation, are mandatory to understand their biological nature, prognosis, and treatment outcome.