[Meningiomas: morphologic and ultrastructural characteristics of psammoma bodies].

In this study we analyzed the morphologic and ultrastructural characteristics of the psammoma bodies in ten meningiomas of different histologic subtypes, characterizing the components of the psammoma body and the elements of the tumor, such as the capillaries and degenerative cells that have been classically considered as initiators of the formation of these calcareous is structures. The discussion considers the diagnostic interest of psammoma bodies in central nervous system tumors, as well as its histogenesis. The different points of view explaining biological mineralization in other territories of the organism are analyzed, as well as the formation of psammoma bodies, comparing the morphologic data obtained in this study. It is concluded that the mineralization of the psammoma bodies is induced principally by the collagen fibers synthesized by the meningocytes and that the form of mineralization is spherical and growth is radial, controlled by the tumoral cells.