Abstract

Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids syndrome (CLIPPERS) is a newly described CNS inflammatory disorder involving predominantly the midbrain and the cerebellum, which is generally described by mild clinical symptoms related to brainstem involvement. Since its introduction in 2010, about 80 cases have been reported throughout the world. The CLIPPERS pathogenesis is largely unknown, being histologically charecterized by nonspecific T-cell lymphocytic perivascular infiltration of co-existent white and grey matter. The most recent diagnostic criteria were proposed in 2017; as there is currently no biomarker available, a strict clincal, radiological and pathological definition is necessary. However, the diagnosis still remains challenging. MRI findings and neuropathological biopsy findings help distinguish CLIPPERS from non-CLIPPERS. Response to steroids is common, patients are initially treated with a high dose 5-day course of daily intravenous methyl prednisone, followed by prolonged treatment of oral prednisone daily. Prolonged immunotherapy is typically required for best outcomes.