Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (Q84151)

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is characterised by a subacute pontine-centric brainstem syndrome including ataxia, dysarthria, diplopia, and facial numbness with a hallmark MRI feature of punctate curvilinear patchy gadolinium enhancement “peppering” the pons (sometimes extending to involve adjacent structures) and which by definition responds to corticosteroid treatment. Extensive investigations are necessary to exclude alternative etiologies. Although brainstem/cerebellar biopsy is helpful and typically reveals a perivascular, predominantly CD3-positive T cell infiltrate it is not necessary for the diagnosis.