[A case of primary progressive multiple sclerosis with improvement in cognitive impairment by anti-CD20 monoclonal antibody therapy].

The patient was a 44-year-old man who developed cognitive impairment beginning at the age of 35 years that gradually worsened. The cognitive impairment led to a difficult social life, and he retired from his company. After hospitalization and workup, he was diagnosed with primary progressive multiple sclerosis (PPMS) that presented only with cognitive impairment for 10 years. Since he had multiple predictive factors for poor prognosis, anti-CD20 monoclonal antibody therapy was implemented. Cognitive impairment and cerebral blood flow SPECT findings improved, and he returned to a social life 3 months later. Anti-CD20 monoclonal antibody therapy was effective in improving cognitive impairment in a case of an advanced stage of PPMS.