Computed tomography and clinical features of Ewing's sarcoma/primary neuroectodermal tumors of the kidney: A case report and literature review

Background : Ewing's sarcoma/primary neuroectodermal tumors (EWs/PNETs) originating in the kidney have been rarely reported. To date, EWs/PNETs have not been demonstrated to have specific clinical characteristics and imaging findings. Case Presentation : A 13-year-old boy was admitted to the hospital with abdominal pain following minor trauma. The patient underwent CT examination on the doctor's recommendation, which revealed contusion of the left kidney and the possibility of a space-occupying lesion in the lower pole of the left kidney. Hence, laparotomy was performed at our hospital, followed by excision of the left kidney, tumor detection and removal of hematoma. The pathological diagnosis was left kidney EWs/PNET with hemorrhagic infarction. Postoperatively, the patient did not receive radiotherapy or chemotherapy. After three months, the patient returned to the hospital for Positron Emission Topography (PET)/CT examination, and no obvious signs of tumor recurrence and metastasis were found all over the body. To date, the patient has been followed-up for 15 months, and remains alive and healthy. Conclusion : EWs/PNETs are highly invasive tumors, with frequent distant metastasis at diagnosis. Hence, early diagnosis and surgical removal of tumor tissue is critical for the prognosis of patients. CT can be used as the primary auxiliary examination of primary renal EWs/PNET. Cystic necrosis is found in the tumor tissue on the CT image. Moreover, cystic necrosis located around the tumor and septal enhancement are observed on the CT enhanced scan, which is helpful for the diagnosis of primary renal EWs/PNET.