Primary progressive multiple sclerosis: part of the MS disease spectrum or separate disease entity?

Acta Neuropathol. 2012 May;123(5):627-38. doi: 10.1007/s00401-012-0953-0. Epub 2012 Feb 11.


Multiple sclerosis (MS), the most frequent demyelinating disease, is characterized by a variable disease course. The majority of patients starts with relapsing remitting (RR) disease; approximately 50-60% of these patients progress to secondary progressive (SP) disease. Only about 15% of the patients develop a progressive disease course from onset, termed primary progressive multiple sclerosis (PPMS); the underlying pathogenic mechanisms responsible for onset of the disease with either PPMS or relapsing remitting multiple sclerosis (RRMS) are unknown. Patients with PPMS do not show a female predominance and usually have a later onset of disease compared to patients with RRMS. Monozygous twins can be concordant or discordant for disease courses indicating that the disease course is not only genetically determined. Primary progressive multiple sclerosis and secondary progressive multiple sclerosis (SPMS) share many similarities in imaging and pathological findings. Differences observed among the different disease courses are more of a quantitative than qualitative nature suggesting that the different phenotypes are part of a disease spectrum modulated by individual genetic predisposition and environmental influences. In this review, we summarize the knowledge regarding the clinical, epidemiological, imaging, and pathological characteristics of PPMS and compare those characteristics with RRMS and SPMS.

Publication types

  • Review

MeSH terms

  • Brain / pathology*
  • Disease Progression
  • Female
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Multiple Sclerosis / classification*
  • Multiple Sclerosis / pathology
  • Multiple Sclerosis / physiopathology
  • Multiple Sclerosis, Chronic Progressive / diagnosis*
  • Multiple Sclerosis, Chronic Progressive / epidemiology
  • Multiple Sclerosis, Chronic Progressive / physiopathology*