An exceptional oncological enigma: primary renal Ewing sarcoma in a clinical context-a case report.

Primary renal Ewing sarcoma/primitive neuroectodermal tumor (PNET) is a very rare and aggressive malignant tumor. We report a case of a young adult who presented with painless hematuria and acute urinary retention and was subsequently diagnosed with localized left renal Ewing sarcoma following robotic-assisted retroperitoneal partial nephrectomy. Histopathology revealed a tumor composed of nests and lobules of monotonous tumor cells with round nuclei, indistinct nucleoli, and scanty cytoplasm, associated with a vascular-rich to hyalinized stroma and fibrillary neural matrix. Moderate nuclear pleomorphism, scattered necrosis, and pseudorosette formation were noted. Immunohistochemical studies demonstrated tumor cell positivity for CD99 and CD117. The patient was subjected to chemotherapy. Early diagnosis and multimodality treatment play an important role in improving survival rate.