Isolated painful trigeminal neuropathy as an unusual presentation of chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids: A case report.

Background Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is an inflammatory central nervous system disorder, typically presenting with subacute symptoms referable to brainstem and cerebellar pathology. This is the first report of CLIPPERS presenting with a painful trigeminal neuropathy. Case report We report an unusual case of CLIPPERS presenting with facial pain and sensory symptoms, in the absence of other brainstem or cerebellar signs. Perivascular enhancement of peri-pontine structures on neuroimaging, lymphocytic infiltrate on histopathology and rapid clinical and radiological responsiveness to glucocorticosteroids were key to diagnosis. Extensive investigations excluded various differential aetiologies. Conclusion The pathogenesis of CLIPPERS is poorly understood, and the diagnostic criteria are yet to be validated. In this case, facial pain was not associated with other brainstem or cerebellar signs, broadening current understanding of how CLIPPERS may present. This has clinical implications in guiding future investigations for patients presenting with painful trigeminal neuropathy.