The CLIPPERS syndrome first describe for Pittock et al in 2010 as a brainstem encephalitis with a characteristic pattern of gadolinium enhancement on MRI, manifest by hyperintense punctiform lesions in T2 and FLAIR with contrast enhancement in T1 the bridge and midbrain has a particular punctiform pattern and  may affect spinal cord and base ganglia. 

Subacute pontocerebellar dysfunction, with or without CNS symptoms, cognitive dysfunction or myelopathy

Neurological symptoms that respond to corticosteroid therapy

There ir absence of peripheral nervous system disease, and lack of a better alternative explanation for the clinical presentation

Neuropathology:

Dense lymphocytic inflammation with perivascular predominance and diffuse parenchymal infiltration; Both white and gray matter could be involved. T cells that predominate in infiltration (CD4> CD8) with variable macrophage components. Absence of myelin loss or secondary myelin focal loss.

Some authors and investigators since 2010, as the groups of Dr. Pittock, Dr Biotti, Dr Gabilondo, Dr Jones, Dr Kastrup, Dr Simo, Dr Taieb, Dr Tohge , Dr Sempere, Kerrn-Jenspersen,  analize the CLIPPERS, and some other authors analize the alternative diagnoses initially suspected as CLIPPERS by Dr De Graff , Dr Buttman, Dr Symmonds, Dr Weng and Dr Ortega. 

Concern the common observation for CLIPPERS as a  unique condition or group of disorders with ataxia, brainstem symptoms, and pontine perivascular contrast-enhancement on MRI.