Rheumatoid arthritis (RA) and multiple sclerosis (MS) are both autoimmune diseases that share similar pathogenesis, but the development of MS in RA patients without the treatment of anti-tumor necrosis factor-alpha is rarely reported, which might be attributed to the use of other medications with potential immunosuppressive effects in the treatment of RA. Since MS can be clinically silent and autopsy examination of the central nervous system in RA patients is rarely described, the association of MS with RA may be possibly under-recognized. We report an autopsy case revealing multifocal inflammatory demyelination in a RA patient who had a prolonged use of methotrexate and hydroxychloroquine resulting in hydroxychloroquine-induced myopathies and heart failure. The neuropathological features of this case are consistent with MS, although there are some altered inflammatory demyelinating features such as relatively smaller lesions and less infiltration of inflammatory cells, particularly T-cells. Our present case, in combination with literature review, suggests that the RA treatment especially with hydroxychloroquine and methotrexate is likely to alter the characteristics of inflammatory demyelination and disease course.