Is dedifferentiated chondrosarcoma a 'de-differentiated' chondrosarcoma?

Since its first description 30 years ago, dedifferentiated chondrosarcoma h as been the prototype of all dedifferentiated sarcomas, The presence of two tumour portions of different mesenchymal differentiation lineages in these neoplasms gives rise to three key questions, which are on the way to being resolved, Does it split up? And if so, how does it split up and when does it split up? Accumulating data provide evidence for a common monoclonal ori gin of both tumour portions and suggest that dedifferentiated chondrosarcom a is a paradigmatic neoplasm of mesenchymal transdifferentiaton irt vivo. T wo categories emerge of dedifferentiated chondrosarcomas with different cel l biology: the classical one, with a low-grade chondroid component splittin g up late, and a second type, with a high-grade chondroid component splitti ng up early in tumour development, Copyright (C) 1999 John Wiley & Sons, Lt d.