MRI and pathological findings of rheumatoid meningitis.

Rheumatoid meningitis (RM) is one of the most severe complications of rheumatoid arthritis. The mortality rate of RM is relatively high and diagnosis can be difficult. We present an 80-year-old woman who was diagnosed with microscopic findings of RM after analysis of biopsy specimens taken from a brain lesion. MRI scanning revealed meningeal enhancement in the brain, and the pathological findings were those of meningeal lymphocytic infiltration, vasculitis and rheumatoid nodules. RM is a treatable disease and in this patient RM was diagnosed on the basis of biopsy findings.