The authors describe a case of renal metastasis from chondrosarcoma originating from the rib, with acute clinical onset characterised by serious anemia secondary to retroperitoneal perirenal hemorrhage. No similar cases have been reported in the literature. The interest of this case lies in both the symptomology of the onset and in the metastatic site. From a diagnostic point of view an intraoperative ultrasound scan was useful, revealing the presence of a roundish neoformation, irregularly hypogenic, with a different appearance from anything observed by the authors in other intraoperative ultrasound examinations of renal masses.
