INTRODUCTION

Multiple sclerosis is one of the neurological diseases which were defined relatively early in the history of medicine. Descriptions of its macroscopic pathology first appeared during the 18th century, and a detailed summary of histological findings was given by Charcot (1868), whose basic study of MS can be regarded as the starting point for the intensive research into its clinical features, pathology, and pathogenesis which followed.

The clinical definition of MS includes a chronic relapsing or progressive disease course, and signs and symptoms which suggest the presence of multifocal lesions in the CNS. Neuroimaging, electrophysiology, and laboratory tests on the cerebrospinal fluid (CSF) may also help to establish the clinical diagnosis. In neuropathological terms, MS is defined as an inflammatory demyelinating disease of the CNS, which is characterized by chronic perivenous inflammation, multifocal plaquelike demyelination, and reactive glial scar formation. It is obvious that this neuropathological definition not only includes the typical cases of chronic MS, but also atypical cases of acute or monophasic manifestations of this disease. In addition, on the basis of neuropathology, MS is only one member of a larger family of diseases, the socalled inflammatory demyelinating disorders (Hallervorden 1940; Adams and Kubik 1952). These diseases may have an acute or chronic course, they may affect both the central and the peripheral nervous systems, and they may also present as transitional forms between the more clearly defined disease entities (Marburg 1906; Hallervorden 1940; Adams and Kubik 1952; Krücke 1973).