Progressive multifocal leukoencephalopathy in a patient with rheumatoid arthritis and polymyositis.

We describe a young woman who developed postpartum rheumatoid arthritis, polymyositis and small vessel cerebrovascular disease. Subsequently she developed biopsy proven progressive multifocal leukoencephalopathy (due to JC virus infection) which may have been a complication of her immunosuppression. This rare complication of autoimmune rheumatic diseases is discussed.