Acervulus Cerebralis

ACERVULUS CEREBRALIS (from Latin acervulus - sand and cerebralis - brain), small calcareous granules that appear and accumulate with age in the meninges, choroid plexus, and pineal gland of the brain. Additionally, they may sometimes be found in very large quantities in certain tumors (fibromas and fibro-endotheliomas) of the meninges, which in such cases are called psammomas (see). Under the microscope, the granules have a layered appearance, for which reason they are also called corpora arenacea (layered bodies). The A. s. forms as a result of the layered deposition of calcium salts in various hardened and hyalinized foci. Apparently, such a basis for calcification are dying and concentrically layered endothelial cells, hyalinized bundles of connective tissue, and obliterated small blood vessels. In the pineal gland, A. s. has a different origin, forming by impregnation of an amorphous protein mass with calcium salts, which brings these granules closer to true concretions. A. s. has no pathological significance.