A cerebral phenotype of chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids: A case report and review of the literature.

CLIPPERS (chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids) is an inflammatory central nervous system disorder that gives rise to brainstem symptoms such as diplopia and articulatory disorders. It shows characteristic "salt-and-pepper" enhancing brainstem lesions on magnetic resonance imaging (MRI) scans. We present an unusual case of CLIPPERS, in which a 29-year-old man initially presented with a seizure. Brain MRI revealed faint open-ring enhancements in the right frontal lobe, and a brain biopsy was performed to make a definitive diagnosis. Immunohistological tests showed perivascular infiltration by primarily CD3- and CD20-positive cells, albeit including a few CD68-positive cells, which confirmed a diagnosis of CLIPPERS. Both the symptoms and the MRI findings were markedly improved by 3 courses of steroid (methylprednisolone) pulse therapy, followed by oral steroid (prednisolone) administration. This case shows that CLIPPERS can present as a phenotype of cortical lesions and seizures as the first signs. A brain biopsy should therefore be actively carried out for differential diagnosis, especially when other, cortically based inflammatory disorders are suspected.