[A Case of Primary Ewing Sarcoma of the Kidney Treated with Multidisciplinary Approach]

A woman in her 40s visited our hospital for further examination and treatment of a left renal tumor. Imaging studies showed that the patient had a large left renal tumor, 10.5 cm in diameter, which contained foci of necrosis. Open left radical nephrectomy was performed. In pathological examination, hematoxylin-eosin staining showed uniform small round cells with alveolar growth. Immunohistochemistry findings showed that CD99 and NKX2. 2 were positive, and synaptophysin was focally positive. Fluorescence in situ hybridization confirmed (11 ; 22) (q24 ; q12) chromosomal translocation which led to diagnosis of primary Ewing sarcoma of the kidney. Two months after the surgery, new tumors were found inside and outside of the left psoas muscles and in the left paracolic gutter. Six courses of chemotherapy were administered with VDC (vincristine/doxorubicin/cyclophosphamide) and IE (ifosfamide/etoposide). After completing the combined chemotherapy, the recurrent tumors disappeared completely on imaging. To prevent further recurrence, external radiation was administered to the left retroperitoneal region. About 16 months after the surgery, numerous new tumors appeared in the left retroperitoneal, left pleura, and erector spinae muscles. Chemotherapy was resumed following radiotherapy, and then trabectedin was administered. However, she eventually died of progressive disease at 26 months after the surgery.