Leiomyosarcomas are extremely rare renal tumors. As to symptoms, they do not differ from other malignant neoplasms of the kidney. In one case diagnosis revealed a sclerosed tumorous necrosis. Therapeutically, it is also in leiomyosarcoma that surgery is the approach of choice since other methods of treatment failed to show significant advantages. Bearing in mind the more fulminant growth of sarcomas, the prognosis is in general poorer than with the remaining malignant renal neoplasms.