Abstract
Soft tissue sarcomas are rare mesenchymal tumors. Amongst others, primitive neuroectodermal tumors (PNET) of the kidney and synovial sarcoma of the kidney belong to the group of soft tissue sarcomas. Synovial sarcomas can occur almost anywhere in the body, most frequently, however, in the lower (62%) or upper extremities (21%). Metastases occur in 50-70% of cases, and thus the prognosis is poor. PNETs are rare, highly aggressive neoplastic lesions which mainly occur in the torso or axial skeleton in young adults. The prognosis is poor with a 5-year disease-free survival rate of 45-55%. The primary therapeutic approach is surgical resection. Most randomized studies assessing adjuvant chemotherapy for all types of localized soft tissue sarcomas did not show statistically significantly better overall survival times after chemotherapy, although they did show longer progression-free survival. We report on two cases of primary renal synovial sarcoma and one case of PNET of the kidney.