Pediatric-Onset CLIPPERS: A Case Report and Literature Review

Abstract

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare neuro-inflammatory disorder with only 10 pediatric cases reported worldwide. The diagnostic criteria proposed in 2017 [1] require clinical criteria (pontocerebellar dysfunction with an exquisite response to steroids, in the absence of peripheral neurological disease and other explainable etiology) and radiological criteria (homogenous gadolinium-enhancing nodules of less than 3 mm, predominantly in the perivascular regions of pons and cerebellum, which resolve with steroid therapy) to be fulfilled for probable CLIPPERS and additional histopathological criteria (lymphocytic, predominantly T-cells, infiltrating perivascular sites) for definite CLIPPERS. In 2019, revised criteria [2] that included a change in the size of the nodules to less than 9 mm, were proposed to improve diagnostic specificity. CLIPPERS has different outcomes between children and adults, as at least 30% of pediatric cases were associated with alternative diagnoses such as familial hemophagocytic lymphohistiocytosis (fHLH) and 20% had residual severe disabilities [2,3].We report a case of probable pediatric CLIP-PERS with a good outcome in a patient who presented with acute cerebellar signs and classical post-gadolinium brain magnetic resonance imaging (MRI) features of punctate lesions of the hindbrain and responded exquisitely to steroids. He was also screened for fHLH, and no known genetic mutations were detected.A previously well 10-year-old boy presented with a 1-week history of progressive headache, diplopia, and unsteady gait, with no other neurological or systemic symptoms. There was a history of pancytopenia attributed to viral illness 3 years ago that had self-resolved. On examination, he was afebrile and had a full Glasgow Coma Scale score with appropriate behaviour for his age. He had truncal ataxia and a broad-based gait with past pointing, dysdiadochokinesia, and intentional tremors bilaterally. There was no ophthalmoplegia, fundoscopy showed no optic neuritis or papilledema, all other cranial nerves were intact, and the tone, power, and reflexes of both upper and lower limbs were normal. There was no hepatosplenomegaly or lymphadenopathy, and the findings of other systemic examinations were normal.Investigations were conducted with the aim of ruling out infection, posterior circulation stroke, demyelination, or malignancy. His full blood