[New classification of bone dysplasias based on histogenetic changes]

Several attempts have been made to classify constitutional diseases of ossification. The one from the Roman group is at present the most accepted. Based on histogenetic concepts and on conventional microscopic studies of our casuistics, we are proposing a new systematization of bone dysplasias considering the mechanisms that lead to the transformation of primitive bone tissue into adult bone tissue. Changes in bone histogenesis may take place at the following levels: 1. In the bones of connective ossification. 2. In the chondrocytic fertile cartilage. 3. In the bony trabeculae. 4. In the periosteum and endosteum. 5. In the bony fibrose tissue. Based on such changes, we classify bone dysplasias into: 1. Connective-dysplasias. 2. Chondro-dysplasias. 3. Trabecular-dysplasias. 4. Periosteo-endosteo-dysplasias. 5. Fibro-dysplasias. 6. Mixed types.