Primary Ewing sarcoma/primitive neuroectodermal tumors of the kidney: Case series of eight cases from a single center with follow-up details.

Introduction: We aim to share the experience of a single center in the management of eight cases of renal primitive neuroectodermal tumor (PNET) which are uncommon, aggressive tumors. The objectives were to study the presentation of the disease, the treatment offered and its outcomes, and the comparison of the treatment with published literature. Methods: The single-center renal PNET data of all patients were retrospectively reviewed from 2011 to 2022. Renal PNET was seen in eight patients. Minimum follow-up period of 1 year was required. Results: Male-to-female ratio was 7:1. The mean age was 26.5 years. All were locally advanced tumors on presentation. One patient had an inferior vena cava thrombus, one patient had metastases on presentation, and two patients had tumor extending to paranephric space. The diagnosis was made by histopathology supported by immunohistochemistry showing CD99 positivity. All patients were treated with radical nephrectomy, followed by chemotherapy in all and radiotherapy in three patients. Two patients expired at 3½ and 6 years after surgery, the remaining six are alive at a median follow-up period of 34.5 months. Conclusion: Renal PNET is an uncommon renal tumor which is aggressive and requires multimodal therapy for prolonged survival.