[Semimalignant skeletal tumors (author's transl)].

Osteoclastoma, chondroma and chordoma are tumors of the skeletal system which have some common features: in spite of benign histological findings their clinical course is that of a malignant neoplasm. They show an aggressive growth and a high rate of recurrencies mainly when the initial therapeutic procedure was insufficient. Osteolysis is the principal sign in the roentgenogram. However, there is no correlation between the roentgenogram and the dignity of the tumor. The best therapy is the radical operation. A good cooperation between surgeon, radiologist and surgical pathologist is very important for the prognosis of patients with this lesion.