Atlas of Diagnostic Pathology (2) : Central Nervous System 2: Non-neoplastic Lesions

Disorders of the central nervous system (CNS) and other organ systems are classified into (1) injuries by mechanical and environmental factors, (2) inflammatory diseases by infections and autoimmune mechanisms, (3) circulatory disturbances by cerebrospinal vascular disorders and coagulative abnormalities, (4) congenital and acquired metabolic diseases, (5) neurodegenerative diseases, (6) congenital malformations, and (7) neoplasms. The CNS consists of both the neuroectodermal parenchymal components such as neurons, astrocytes and oligodendroglia, and the mesodermal mesenchymal components such as microglia, vessels, meninges and choroid plexus. When the CNS is exposed to pathological conditions, these components could exhibit a variety of morphological changes through tissue responses represented by regression, regeneration and proliferation of the cells. CNS disorders are characterized by pathophysiological and anatomical profiles. It is particularly important to determine where the lesions are localized in the CNS, whether the distribution of the lesions is focal or diffuse, solitary or multiple, symmetric or asymmetric, systematic or nonsystematic, or synchronous or metachronous, and whether the corresponding clinical course is acute or chronic, progressive or static, or paroxysmal or continuous. Pathological findings are graded into (1) specific and critical, (2) characteristic and consistent, or (3) insufficient levels for diagnosis. This article focuses on the circulatory, inflammatory, neurodegenerative, and metabolic disorders of the CNS, by demonstrating their pathological features