Collateral venous flow through uterus caused by retroperitoneal extraosseous Ewing sarcoma.

We report on a twenty-four-year-old woman with extraosseous Ewing sarcoma in the right retroperitoneum. The tumor blocked the common iliac vein, and because of an intervening pregnancy, the blood flow was shunted through the uterus and left ovarian vein back into the vena cava. She died within nine months despite radical surgery, radiotherapy, and chemotherapy.