TABLE 2.

Histologic parameters of MS and its variants

Disease	Cellular contributionsa of:
	Mononuclear infiltratesb	Foamy macrophagesc	Astrocytes
Acute MS	+++	++	++d
Diffuse sclerosis (Schilder type)	++	+++	+++d
Chronic MS	+F	+F	+++e

^aCellular contributions are rated as follows: +, scant; ++, moderate or intermediate; +++, pronounced. The topographic distribution of all the cell types is diffuse unless indicated otherwise by the superscript letter F, for focal. With focal distribution, infiltrates involve the walls and perivascular spaces of scattered intralesional vessels. 

^bComprised predominantly of lymphocytes and monocytes and to a lesser extent of immunoblasts and plasma cells. 

^cMyelin-laden macrophages, which are present in the Virchow-Robin (perivascular) spaces and also throughout the white matter substance. 

^dPrincipally hypertrophic (large cell bodies). 

^ePrincipally fibrous (fibrillary).