Synchronous Retroperitoneal Schwannoma and Incidental Papillary Renal Cell Carcinoma: A Case Report

Background: retroperitoneal schwannoma is a rare tumor rising from schwann cells in peripheral nerve sheaths. retroperitoneal schwannoma is really infrequent and has nonspecific symptoms and imperfect radiologic features, and is often identified histologically after surgery. case report: we report the case of a 73-year-old man presented with flank mass. imaging shows a hypoechoic macro lobulated solid cystic mass in retroperitoneum. intraoperatively, after complete resection of retroperitoneal mass, a suspected lesion in upper pole of right kidney was observed. histopathology evaluation after surgery shows coexistence of a large retroperitoneal schwannoma and papillary renal cell carcinoma, type 1. conclusion: schwannoma should be considered in the differential diagnosis of retroperitoneal spindle cell tumor. schwannoma coexisted with renal cell carcinoma in a patient is an unusual event. thus, it can show the importance of appropriate evaluation before any surgery.