Introduction: There is no clear radiologic or pathologic agreement on the differences between enchon-droma and conventional chondrosarcoma, which has huge therapeutic consequences. Microscopically,an enchondroma is composed of ôislands of intramedullary hyaline cartilage surrounded by marrow fat",and a chondrosarcoma a ôdiffuse cartilaginous replacement (invasion) of the marrow which leads tocomplete trapping' of host lamellar bone trabeculae." The marrow around islands of cartilage shouldbe detectable on magnetic resonance imaging (MR). Enchondroma may be the precursor of chondrosar-coma; benign cartilaginous islands are often seen microscopically at the periphery of chondrosarcoma.We attempted to detect these islands at the periphery of chondrosarcomas on MR and correlate themmicroscopically.Materials and methods: We examined our database for all patients with a chondrosarcoma of the longand flat bones between 1990 and 2007. Only those with a preoperative MR who underwent an en blocresection were included, yielding 32 patients. We looked for low-signal islands surrounded by high (fat)signal on T1-weighted images, and high-signal islands surrounded by low signal on T2-weighted fatsaturated images at the periphery of the main tumour mass. Microscopic correlation was performed inall cases.Results: On microscopy, there were 23 conventional chondrosarcomas, nine dedifferentiated. Peripheralislands surrounded by fat were detected on MR in 19 cases, corresponding to benign cartilage in 18cases and to the benign scar of a needle biopsy tract in one. There were no peripheral islands detectedradiographically or microscopically in 13 cases.Conclusion: Cartilaginous islands microscopically detected at the periphery of some chondrosarcomasare easily and reliably diagnosed on MR.
- Magnetic resonance imaging
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging