Intracranial rheumatoid nodule causing recurrent transient neurological deficits

A 67-year-old man with rheumatoid arthritis developed recurrent acute onset of stereotyped focal neurological abnormalities. Cerebral imaging showed a mass lesion in the left parieto-occipital lobe. Imaging did not show the time evolution expected in stroke and so he underwent an extensive workup, which was inconclusive. Brain biopsy identified a rheumatoid nodule causing an extensive inflammatory reaction that mimicked a mass. Following treatment with intravenous corticosteroids and rituximab infusions, his clinical condition improved. While rheumatoid meningitis is well recognised, a rheumatoid nodule in the brain rarely presents as a mass lesion. Nevertheless, it is important to consider rheumatoid nodule in the differential diagnosis of a cerebral mass lesion in patients with rheumatoid arthritis.