Renal Ewing\'s sarcoma with the spread of tumor thrombosis to the inferior vena cava: case report

Background: Ewing's sarcoma/Primitive neuroectodermal tumor (PNET) is a group of tumors with small round cells that originate from nerve stem cells. They are generally more common in children and often occur in the soft or bony tissues of the limbs, trunk, head, and neck. Ewing's sarcoma is a rare disease in the kidney and its tumor thrombosis into Inferior Vena Cava (IVC) is assumed as a very rare condition. Case Presentation: The patient was a 14-year-old boy who underwent an MRI of the thoracic and lumbar vertebrae due to paresthesia of the lower limbs, which showed the presence of the mass in the vertebrae of T3, T4, T5, and concurrently right kidney. The pathology report confirmed the diagnosis of Ewing’s sarcoma, PNET. The patient underwent T4 laminectomy and bone mass resection and then received 4 courses of chemotherapy with VAC + IE. In the next stage of treatment, the patient had abdominal MRI and MR Venography (MRV) that demonstrated a mass in the middle of the upper right kidney with a 10 cm length tumor thrombosis into IVC with extension to the suprahepatic area and involvement of several aortocaval lymph nodes. In January 2020, the patient was operated in Imam Khomeini Hospital Complex, Tehran by a midline incision, at first, the kidney artery and vein were controlled, and without thrombectomy, the IVC was controlled from above and below the liver, then the tumor thrombosis was removed. The right kidney underwent a radical nephrectomy. Three days later, the patient was discharged in good general condition and referred for chemotherapy. Conclusion: Because Ewing's sarcoma is a rare condition in the kidney, this case is considered a very rare case due to its tumor thrombosis. This case study showed that despite the advanced stage of the disease, early diagnosis and treatment of patients with Ewing's sarcoma, along with adjuvant treatments can play an important role in the survival of these patients.