Basal ganglia mass lesions in juvenile rheumatoid arthritis.

A 2-year-old boy suffered aphasia, hypotonia, dystonia, and loss of activity and spontaneous speech during an active stage of juvenile rheumatoid arthritis with pericarditis, fever, anemia, and a high antinuclear antibody titer. These neurologic signs slowly improved with corticosteroid treatment but fluctuated over 1 year. The neuroimaging studies revealed irregular mass lesions in the basal ganglia bilaterally mainly involving the globus pallidus. They gradually decreased in size and almost disappeared after 1 year. A stereotactic brain biopsy revealed a slight proliferation of astrocytes. Chorioretinitis was also observed during the clinical course. A chronic inflammatory process involving cerebral vessels was suspected, although angiography did not demonstrate cerebral vasculitis. The possibility of central nervous system lymphoma could not be eliminated. The type of aphasia and the relation to the lesion sites are discussed.