Case report 459: Fibrosarcomatous dedifferentiation of chondrosarcoma of the tibia

A patient with fibrosarcomatous dedifferentiation of chondrosarcoma of the tibia was studied, utilizing plain radiographs and magnetic resonance imaging (MRI) with both T1 and T2-weighting. Following amputation, the surgical specimen was transected in the sagittal plane and representative histological sections were obtained. The results were correlated with the plain film and MRI findings. Although the tumor appeared inhomogeneous on the T1 and T2-weighted MRI images, no correlation existed between the signal strength of a given region of interest and its histological cell type. Plain film findings, such as matrix calcification and cortical destruction, were more helpful in predicting malignant dedifferentiation of chondrosarcoma. MRI was clearly superior to plain radiographs in demonstrating the extent of the lesion within the medullary cavity and in the soft tissues. (orig.)