Retroperitoneal Ewing sarcoma requiring nephrectomy for local control

Abstract

Ewing sarcoma is a small round blue cell tumor that most commonly involves bony structures in the pediatric population. Less commonly, it presents in the soft tissues of other anatomic areas including the limbs and trunk, and rarely, the retroperitoneum. In this report, we present the case of a 15-year-old girl who presented with vague abdominal complaints and was found to have a left retroperitoneal Ewing sarcoma that was densely adherent to, but not arising from the left kidney, as well as a calcified lesion of the left adnexa. She was treated with neoadjuvant chemotherapy and underwent resection via a combined laparoscopic approach for the adnexal mass, and laparotomy for the retroperitoneal Ewing sarcoma, which also required left nephrectomy for adequate local control of the tumor. Given the rarity of this tumor in the retroperitoneal location, this patient's treatment course benefited from a multidisciplinary discussion and plan.