[Retroperitoneal neoformation: case study].

Retroperitoneal sarcoma represents approximately 12-15% of all sarcomas and between 0.2 and 0.5% of all neoplasia. They very rarely metastasize, and the main cause of death is local recurrence. Radiotherapy and chemotherapy still do not represent valid therapeutic alternatives, therefore radical surgery remains the only valid option. We would like to present the following case of a 48-year-old male patient. After episodes of right-side renal colic, a 19x16x19 cm mass was found, which was palpable in the right quadrants, englobed the right ureter and caused ipsilateral hydroureteronephrosis of medium grade. Surgery allowed total excision of this neoplasm (which was tenaciously attached to various organs), with the sacrifice of the right kidney. The final histological examination on a sample taken during surgery confirmed that the neoplasm was a spindle-cell sarcoma at an intermediate grade of malignancy. One year after surgery the patient is disease free.