A spontaneously ruptured primitive neuroectodermal tumor of the kidney: a case report and treatment strategy

Ewing sarcoma family tumor, including Ewing sarcoma (EWS), primitive neuroectodermal tumor (PNET), and Askin’s tumor, is a group of poorly differentiated, aggressive malignancies that typically arise in bone, soft tissues, and chest wall, respectively. EWS/PNET occurs rarely as a primary renal neoplasm. Renal EWS/PNET exhibits highly aggressive biological behavior and poor prognosis. Treatment strategies for EWS/PNET include surgery, chemotherapy and radiotherapy. A 39-year-old man was admitted with right flank pain and hematuria. An urgent abdominal computed tomography with contrast revealed a 11 × 7 cm, slightly enhanced solid mass in the right lower pole of kidney with rupture and retroperitoneal hemorrhage. Selective angiograms of the right renal artery and transcatheter arterial embolization (TAE) were performed. Following the embolization, his vital sign stabilized. Two days after the TAE, the patient underwent right nephrectomy and adrenalectomy. The histopathological specimen showed sheet-like monotonous proliferation of small round cells with hyperchromatic oval prominent nuclei. Immunostaining technique showed positive CD-99, neuron-specific enolase and vimentin, leading to the diagnosis of PNET. Adjuvant chemotherapy with nine courses of VAIA (vincristine, actinomycin D, ifosfamide, and doxorubicin) was performed. There was no recurrence 17 months after the operation. Our report is the second case of spontaneously ruptured renal PNET. We review the published series of the renal EWS/PNET and comment the treatment strategy of renal EWS/PNET.