The pathology of multiple sclerosis: evidence for heterogeneity.

The idiopathic inflammatory demyelinating diseases (IIDDs) consist of a broad spectrum of disorders that vary in their clinical course, regional distribution, and pathology. Though pathology of these demyelinating disorders demonstrates extensive interindividual heterogeneity, there is notable homogeneity within individual patients. The relation between the diverse underlying pathology of IIDDs and the various clinical, paraclinical, and radiological findings is unclear. Finding less-invasive clinical or paraclinical surrogate markers, which accurately and reliably predict the underlying distinct pathologies within the family of IIDDs, can potentially guide future therapies that better target specific pathogenic mechanisms.