Corpora Arenacea

CORPORA ARENACEA, sand bodies (Latin corpus-body and arenaceus-sandy), synonym corpora psammosa, small (about 20-40 μm) rounded formations, like grains of sand, of dense consistency, with concentric lamination on cross-section. Their inner layers contain calcium salts, while the outer layers are usually free from lime. S.a. occur normally in the choroid plexus of the brain and in the dura mater, accumulating here with age and forming the so-called brain sand, acervulus cerebralis (see). In addition, S.a. are found in tumors, for example in fibromas, fibrosarcomas and fibroendotheliomas of the meninges and (less frequently) other areas of the body, as well as in some cystadenomas and cystocarcinomas of the ovaries, which in such cases serves as the basis for designating such a tumor as psammomatous, a psammoma. When passing a finger over the surface of a tumor cross-section containing S.a., it feels as if it were sprinkled with sand. A very rare location for corpora arenacea is the lungs. On the methods of formation of S.a.-see Acervulus cerebralis.- From S.a., which in the brain are designated as brain sand, one must distinguish the so-called bone sand, which has nothing in common with S.a. The term 'bone sand' refers to the smallest particles of dead bone (small sequestra), which form in the bone and are sometimes exuded with pus in caries.

ibid., Vol. XLIII, No. 11, 1928; Schmidt M., Die Verkalkung (Handbook of General Pathology, ed. by L. Krehl and F. Marchand, Vol. III, Part 2, Leipzig, 1921).