Primary Renal Soft Tissue Sarcoma in Children.

OBJECTIVE: To describe clinical and treatment characteristics of renal soft tissue sarcomas in children, we analyzed a series of patients enrolled in the protocols coordinated by the Italian Soft Tissue Sarcoma Committee (STSC). METHODS: From 1979 to 2011, 2138 patients with soft tissue sarcomas were registered in different STSC protocols, and 12 had a renal sarcoma: 7 primitive peripheral neuroectodermal tumors, 2 undifferentiated sarcomas, 1 rhabdomyosarcoma, 1 desmoplastic small round cell tumor, and 1 kaposiform hemangioendothelioma. Treatment included conservative surgery, chemotherapy according to the guidelines of the protocols, and radiotherapy for high-risk patients. RESULTS: Nephrectomy was performed in 11 children resulting in a complete tumor resection in 7. In 4 patients, macroscopical (1) or microscopic (3) tumor residuals remained postoperatively. Tumorectomy was performed in patients with congenital renal agenesis. All patients received chemotherapy. Seven patients also received postoperative radiotherapy. Overall, 9 patients are alive in first complete remission with a median follow-up of 6.1 years (range, 1.3-21.1 years). Two of the 7 patients with primitive peripheral neuroectodermal tumors (pPNETs) died after an early relapse: 1 had metastatic disease at diagnosis and the other was initially misdiagnosed with Wilms tumor (WT). One child with desmoplastic small round cell tumor (DSRCT) is alive with disease. Two patients developed signs of ifosfamide-related nephrotoxicity. CONCLUSION: In our analysis, pPNET is the most common type of renal soft tissue sarcoma (STS). Prognosis seems satisfactory with the adoption of an aggressive multidisciplinary approach, especially when complete tumor resection is possible. The replacement of ifosfamide with cyclophosphamide could be considered after nephrectomy.