A case of multiple metastatic low-grade endometrial stromal sarcoma

Endometrial stromal sarcoma (ESS) is a rare low-grade malignancy affecting mainly the uterus. Primary extrauterine occurrence of this tumor, involving most commonly the ovary, is exceedingly uncommon, and is retained after excluding an occult or misdiagnosed EES of the uterus.A 79 year-old-woman, with a previous history of hysterectomy for prolapse and leiomyoma, presented with a bilateral ovarian mass. Morphological characteristics suggested ESS with extraovarian spread, peritoneal implants and endometriotic foci. The sections of the previous "leiomyoma" revealed ESS with prominent foci of epithelial-like structures. We discuss through this case clinicopathologic features of ESS, with emphasis on its unpredictable outcome.