Mass lesions in the basal ganglia bilaterally and mainly involving the globus pallidus are reported in a two year old boy with juvenile rheumatoid arthritis from the Department of Pediatrics, Hokushin General Hospital, Nishi, Nagano, Japan. At ten months after the onset of the arthritis he developed a relapse with fever, heart murmur, vomiting, hypotonia, dystonia, and aphasia. Deep tendon reflexes were exaggerated and plantar responses extensor. The abnormal neurologic signs and basal ganglia lesions gradually improved with corticosteroid treatment and almost disappeared after one year. The right optic fundus showed chorioretinitis. A stereotactic brain biopsy performed to exclude a neoplasm revealed proliferation of astrocytes of undetermined origin, either reactive or low-grade astrocytoma. The dystonia subsided after one year but peculiar mouthing behavior persisted. A CNS primary lymphoma could not be excluded. 
COMMENT. A chronic inflammatory process involving cerebral vessels was suspected in this patient but angiography failed to demonstrate a cerebral vasculitis.
Other rheumatic diseases with CNS complications include lupus erythematosus, polyarteritis nodosa and rheumatic fever. Seizures are a common presenting sign of lupus erythematosus.