Multiple sclerosis; perivascular cuffing of lymphocytes: When multiple sclerosis is in its active phase and neurologic function is worsening, an inflammatory component such as exhibited in this slide can be seen. The photomicrograph contains a venule with numerous lymphocytes in the Virchow-Robin space. The tissue around the venule is a portion of a plaque. This inflammatory component is one of the major reasons that multiple sclerosis has been considered to be either a disease with a strong immune basis, or of infectious etiology (or both).