[Osteosis due to primary hyperparathyroidism. The SEM ultrastructural features of the periosteal and endosteal surfaces].

The study of four cases of osteosis caused by primary hyperparathyroidism, tree female and one male, which have undergone surgery for pathological fractures in met-epiphysis bone, allows to analyze with the help of scanning electron microscope modifications occurring in periosteal and endosteal bone matrix. The periosteal surface appears abundantly furrowed by large and deep canals, irregularly joined together. Areas of resorption, these at rest and these of osteodeposition are distributed in changeable but regular way. The bone turnover of endosteal side is particularly accentuated. This surface contains the bone trabeculae residuals and is widely marked by deep Howship's lacunae, which show intense osteoclastic activity. It seem that osteocytes cells participate actively in the process of osteolysis, widening the lacunae and small canals which appear to be surrounded by calcospherites arranged in irregular way. Osteogenetic activity, with large areas of deposition, is very intense, as a defence attempt against osteolytic resorption process.