Multiple sclerosis: a practical review for pathologists.

Multiple sclerosis (MS) is an immune-mediated demyelinating disorder of the central nervous system. It is a chronic disorder resulting in neurologic dysfunction that is disseminated both in time (multiple discrete episodes) and space (involving multiple sites). Histologically, MS is characterized by localized loss of myelin with relative preservation of axons. This review will discuss the epidemiology, clinical, laboratory, radiologic, and pathologic features of multiple sclerosis, as well as briefly touch on the differential diagnosis, treatment, and prognosis of the disease, especially as they relate to the pathologic interpretation of tissue specimens.