Ewing’s sarcoma is a common diagnosis in patients with skeletal disease. Reports of this subtype of sarcoma present an extremely rare occurrence in the diagnosis of kidney cancer in the adult population. It comprises only 1% of all renal tumors. Epidemiological data in Asia and the Philippines has been scarce. A total of 100 case reports have been published worldwide. Around 80% of cases are found in patients under 18 years of age, and less than 1% of cases are found in adults greater than 40 years of age.

A 32-year-old male patient was admitted with a 3-month history of flank pain and sudden weight loss. The patient is a four-pack-year smoker. He is non-hypertensive and nondiabetic. After undergoing an ultrasound of the whole abdomen, it was noted to have a complex hyperechoic mass on the inferior pole of the left kidney. He underwent a CT scan of the abdomen and pelvis with contrast, which revealed a large, mixed solid and cystic mass arising from the inferior pole of the left kidney measuring 17.3cm x 13.7cm x 14 cm. On presentation, the patient’s vital signs were stable. Upon examination, he was negative for hematuria, and a solid, nontender mass was noted upon palpation on the left upper quadrant of the abdomen. He underwent an open partial nephrectomy for the left renal tumor (Figure 2). The resulting specimen was consistent with histomorphologic features of primary extraskeletal Ewing’s sarcoma involving the renal parenchyma and perinephric tissue. There was no involvement of regional lymph nodes.

Nephrectomy with adjuvant Pembrolizumab has been the current management. The 4-year overall survival for patients without metastasis is 85% compared to 47% for patients with metastasis

Primary renal Ewing's sarcoma is extremely rare. The decision toward a nephron-sparing surgery was to give the best possible quality of life to a young adult without compromising the oncologic outcomes.