Dedifferentiated chondrosarcoma. An ultrastructural study.

The light and electron microscopic features of a well-differentiated chondrosarcoma with dedifferentiated foci (dedifferentiated chondrosarcoma) is presented. Ultrastructurally, the cells of the dedifferentiated portion were embedded in a matrix containing numerous short bundles of collagen fibers; these cells showed dilated rough endoplasmic reticulum containing stippled material as well as poorly formed cell junctions and resembled the cells in the cartilaginous component. These findings contrast with those reported previously.