[Electron microscopic study of striatodental calcification (Fahr) (author's transl].

In a woman, aged 52, who had impaired phosphate excretion and low serum calcium levels, abundant calcium deposits (Pseudokalk) were found between the basement membranes of blood vessels in the regions of corpus striatum and nucleus dentatus as well as in the subcortical white matter and centrum semiovale. Calcium deposits were found also outside blood vessels but always in the vicinity of the basement membrane. These can be phagocytozed by makrophages or astrocytes. Calcium deposits have a characteristic ultrastructure. They are built up of 140-400 A electron lucent filaments (acid mucopolysaccharid?) within which electron dark segments built up of 40-80 A units (calcium deposits?) are found. The concentric rings of calcified deposits are of reflection of differing density of aggregation of dark filaments. The growth of the deposits takes place by additional precipitation. In the development of calcification of the cerebral blood vessels in Fahr's disease, the role of high serum phosphate levels, the increased permeability and dysfunction of mesenchymal cells of the vessel walls are discussed.