[An aggressive chondroblastoma mimicking paraosteal osteosarcoma].

We present a rare case of an aggressive form of chondroblastoma arising from proximal radius. Because of an initial histopathologic diagnosis of paraosteal osteosarcoma, the patient was treated with preoperative chemotherapy and afterwards a local tumor resection with one half of proximal radius was performed. A final histopathologic examination revealed typical benign chondroblastoma. We discuss the rare localisation of chondroblastoma and its differential diagnosis with surface osteosarcoma.