[Adult onset Still's disease with a brainstem lesion demonstrated on MRI].

We report a 39-year-old man with seven-year history of adult onset Still's disease (AOSD) who developed left abducens palsy and ataxic gait. T2-weighted MRI demonstrated high-intensities in the left side of the lower pons, including nucleus abducens and the inferior cerebellar peduncle, and in the right anteromedial portion of the thalamus corresponding to his neurological abnormalities. He responded favorably to corticosteroid treatment, and the high-intensities in the T2-weighted MRI diminished subsequently. Previously, he had developed bilateral sensorineural hearing loss which had responded to corticosteroid treatment during an exacerbation of the disease. There was no evidence of multiple sclerosis or other systemic diseases affecting the central nervous system (CNS) in the laboratory findings. Although the precise reason for the MRI lesions was unclear, we thought they were CNS manifestations of Still's disease. We suggest that AOSD is one of the causes of focal CNS involvement in young adults, particularly who has a history of fever of unknown origin.