[Benign retroperitoneal schwannoma. Incidental diagnostic in patient with hematuria of the percusionist].

The incidence of retroperitoneal primitive tumour varies from the 0.3 to 3%. The sarcomas suppose the group but it frequents of retroperitoneal tumour, being the Schwannoma an unusual tumour with an incidence from 1% to 50% of the retroperitoneal primary tumours. The schwannoma also denominated neurinoma or neurolenoma, it is a derived tumour of the cells of Schwann of the outlying nerves. It is characterized by their clinical and radiological inespecify, being the diagnose pathological, with intense positive inmunohistoquimics to the protein S-100. The election treatment is the surgical remove, with wide margins; not being described cases of malignización neither of metastasis at distance, but if the recurrence existence at probably secondary local level to incomplete resection.