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.