DE-DIFFERENTIATED CHONDROSARCOMA IS NOT A DE-DIFFERENTIATED CHONDROSARCOMA

Aims: De-differentiated chondrosarcoma is characterized by the presenc e of two distinct chondroid and nonchondroid tumour portions, The aim of our study was to investigate the distribution of extracellular matr ix components in this tumour entity and thus to shed light on its hist ogenetic origin, Methods and results: Histochemical and immunohistoche mical analyses were performed for collagen subtypes I, II, III and VI and cartilage proteoglycans in three samples of de-differentiated as w ell as conventional chondrosarcomas (various grades), In the chondroid tumour areas of de-differentiated chondrosarcoma, typical cartilage m atrix components could be detected similar to chondroid areas of grade 1 and 2 conventional chondrosarcomas, In contrast, the tumour matrix of the nonchondroid portions of de-differentiated chondrosarcomas cont ained matrix molecules which are typical for fibroblastic tissue, This matrix composition was not identical with less differentiated (noncho ndroid) areas of grade 2 and 3 conventional chondrosarcomas. Conclusio ns: Our results confirm the chondroid nature of the differentiated por tion of de-differentiated chondrosarcoma and indicate a nonchondrocyti c nature of the nonchondroid portion, De-differentiated chondrosarcoma should not be considered as a 'de'-differentiated chondrosarcoma (gra de 4 neoplasm), but as a tumour entity showing two types of mesenchyma l differentiation.