A case of primary retroperitoneal undifferentiated endometrial stromal sarcoma after concurrent chemoradiation therapy for cervical cancer.

Endometrial stromal sarcoma (ESS) is a relatively rare uterine sarcoma, especially extrauterine ESS. Furthermore, retroperitoneal ESS are extremely rare. Up to now, there are only four cases of primary retroperitoneal ESS reported in the literature. We report one case of primary retroperitoneal undifferentiated endometrial stromal sarcoma after concurrent chemoradiation therapy for cervical cancer with a brief review of the literature.