We report an uncommon presentation of kidney synovial sarcoma (KSS) in childhood, discovered by abdominal pain and gross hematuria, associated to radiological and pathological challenges to the diagnosis. After necessary biopsy, adequate chemotherapy, following European Pediatric Soft Tissue Sarcoma Study Group Non-Rhabdomyosarcoma NRSTS 2005 Protocol, completely resection was possible. There are just few cases at global literature review of SSR in child, a good response to treatment is performed a completely resection (R0), besides a close follow-up (strongly recommended). The risk of metastasis is strongly correlated that is why diagnosis represent a big deal.