The intraosseous expansion of primary chondrosarcoma is achieved by osteoclasts expressing GnTase V (MGAT5) activity to drive neoangiogenesis.

We have studied the impact of primary central conventional chondrosarcoma on the bone tissues (trabecular, endosteal and cortical) of the proximal femur. A combination of macroscopy, contact radiography, histology, lectin histochemistry and immunohistochemistry techniques were employed. The tumours expanded by driving the resorption of bone tissue progressively removing trabecular, endosteal and cortical bone ultimately causing pathological fracture of the latter. Resorption of all tissue types was by osteoclasts invariably accompanied by companion mesenchymal tissue containing capillaries, mononuclear cells and mast cells. There were no new pathological mechanisms in play, rather the usurpation of normal physiological mechanisms of bone tissue remodelling and modelling. Lectin histochemistry showed that osteoclasts, endothelial cells and mast cells expressed GnTase V (MGAT5) which has been implicated in neoangiogenesis. The linkage of osteoclasts and new blood vessels we believe is key to successful bone resorption.