[Peri-tumor mandibular demineralization]

This study describes hitherto unpublished observations suggesting mechanism by which a tumor can cause massive resorption of the mandible. Microradiographic analysis of the cancerous areas has shown a mobilization of minerals from compact and spongious bone tissue accompanied by incomplete degradation of collagen fibres. The minerals are deposited in the lumen of the Haversian canals, the medullar cavity and the perimandibular soft tissue, areas which are not normally mineralized. Electronic microprobe and X-ray diffraction analysis revealed that in the mineralized zones undergoing demineralization, and in the heterotropic regions, a transformation of the crystal structure of the calcium phosphate salts had occurred. These zones, composed of hydroxylapatite in normal bone and dental tissue, had changed instead to brushite (known to be stable in acidic conditions). Our observations add a new dimension to the bone marrow demineralization process.