Table 1 Core features of CLIPPERS (adapted from Simon et al.)[2]

Clinical:

-

subacute progressive ataxia and diplopia

Radiological:

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numerous punctate or nodular enhancing lesions bilaterally within one of the three following anatomical locations: pons, brachium pontis (=middle cerebellar punducle), cerebellum

-

individual radiological lesions are small but may coalesce to form larger lesions

-

lesions may occur in the spinal cord, basal ganglia or cerebral white matter but should be decreasing density with increasing distance from the pons.

Corticosteroid responsiveness:

-

prompt and significant clinical and radiological response to corticosteroids

Histopathological:

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white matter perivascular lymphohistiocytic infiltrate with or without parenchymal extension.

-

infiltrate contains predominantly CD3 + and CD20+ lymphocytes.

-

absence of the following histopathological characteristics:

  ○ monoclonal or atypical lymphocyte population

  ○ necrotising granulomatomas or giant cells

  ○ histological features of vasculitis

Differential diagnosis should be excluded:

-

CNS lymphoma, glioma, primary CNS vasculitis, paraneoplastic syndrome, sarcoidosis, demyelinating disease, Behcet’s and Sjogren disease, tuberculosis, neurolues, Whipple’s disease and histiocytosis.