Contributors: Diva R. Salomão and R. Jean Campbell
The dedifferentiated chondrosarcoma is an extremely malignant type of chondrosarcoma. This type of chondrosarcoma was first recognized by Dahlin and Beabout in 1971, who proposed that a low-grade tumor of cartilage may become transformed into a high-grade malignant neoplasm. It has the worst prognosis of all the variants of chondrosarcoma and most cases occur in the sixth decade of life.