[Dedifferentiation of chrondrosarcomas (author's transl)].

The clinical course and the results of radiographic and histological investigations in three patients with dedifferentiated chondrosarcoma are presented. The tumors were characterized by chondrosarcomatous tumor sections of low grade malignancy adjacent to fibrosarcomatous tissue sections. One to two and one-half year after the onset of the first clinical symptoms pulmonary metastases appeared and in one case a subcutaneous mass presented, which had the histological appearance of a fibrosarcoma. Differentiation of a chondrosarcoma customarily has an adverse effect on the prognosis with both the early appearance of metastases and a rapidly fatal clinical course. Cartilagenous tumors of the axial skeleton and the long bones must be extirpated surgically in an early and radical fashion, particularly if there are radiographic signs of proliferation.