Low-Grade Endometrial Stromal Sarcoma in Young Age: A Clinicopathological Report

Endometrial stromal sarcoma (ESS) is a rare tumor of mesodermal origin. It constitutes 0.2 % of all uterine malignancies and represents ~10 % of all uterine sarcomas. It may be mistaken for leiomyoma, as identifying it clinically is difficult and is more often diagnosed postoperatively after a histopathological examination [1]. Classically, ESS appears as a single nodule, multiple solid-cystic masses, or a poorly demarcated lesion with occasional cystic degeneration grossly [1]. Depending on the cellular uniformity, mitotic activity rate ( 10 per ten high-power fields) and presence of hemorrhage and necrosis, ESS is classified as low-grade (LGESS) or high-grade ESS (HGESS). In recent times, however the division of ESSs into low-grade and high-grade categories has fallen out of favor, and the term ESSs is now considered best restricted to neoplasms that were formally classified as LGESS [2]. High-grade tumors without recognizable evidence of a definite endometrial stromal phenotype are now simply termed as endometrial sarcomas [2]. This is because, although half the LGESS are limited to the endometrium, the other half shows focal, worm-like, or diffuse, multiple, nodular permeations in the myometrium from the endometrial foci. This article presents a LGESS with the nodular mass partially located in the myometrium.