Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS): a case presentation

A 24-year-old man presented to our hospital with an established subacute dizziness with gait instability, ataxia, diplopia, dysarthria, dysphagia, slurred speech and quadriplegia. Cerebrospinal fluid analysis revealed elevated white blood cell count with lymphocytes. Extensive laboratory evaluation of serum and CSF biomarkers for autoimmune and infectious causes werd negative.

The patient underwent a brain MRI (3 Tesla).  Axial T2-weighted (Fig.1a) and fluid-attenuated inversion recovery (FLAIR) (Fig.1b) images revealed diffuse patchy hyperintensity of the pons. Apparent Diffusion Coefficient (ADC) map (Fig.1c) through the level of pons show areas without diffusion restriction. Susceptibility weighted imaging (SWI) (Fig.1d) revealed with low signal prominent veins of the pons. Contrast material–enhanced T1-weighted image (Fig.1e) showed linear and punctate foci of enhancement involving the pons. High dose of corticosteroid was administered upon patient hospitalization and continued with oral dose. Three months after treatment, the patient came for a re-examination, and his clinical symptoms had disappeared completely. A follow-up ΜRI was performed and showed significant, almost complete, resolution of the lesions (Fig. 2 a,b,c,d,e). The patient was followed up for more than one year, and there has been no recurrence.

Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS) is a rare, relapsing-remitting disorder of the central nervous system [1,2]. It seems to concern all age groups, mainly young and middle-aged individuals, with a slight predominance in men over women [3]. The diagnosis of CLIPPERS is based on clinical, laboratory and radiological criteria and biopsy if required [4]. The diagnostic criteria consist of the following triad: 1) symptoms from the brainstem, 2) characteristic lesions on MRI, of the punctuate or curvillinear type enriched in the contrast medium, mainly involving the pons, 3) T-lymphocyte infiltrate with a perivascular distribution in the biopsy without inflammation or necrosis of the vessel wall[1]. Biopsy is not necessary if alternative pathologies have been ruled out and good response to corticosteroids [1,3]. CLIPPERS presents common imaging findings with a variety of conditions (eg, lymphoma, multiple sclerosis, vasculitis, encephalitis) [5]. Lesions are mostly bilateral, symmetrical without mass-effect and show mild or no focal edema [2,4] Ιn terms of the distribution of the lesions, these mainly concern the pons, midbrain, medulla and cerebellum and do not usually exceed 3 mm in diameter [2–4]. Τypically lesions are smaller as their distance from the pons increases [4]. A characteristic finding on MRI is multiple foci or patchy or curvilinear enhancing lesions in the cerebellum with or without extension to the cerebellar peduncles and cerebellum [3,4]. The lesions may not be completely clear on T2 and FLAIR sequences but are clearly visualized on T1-weighted image after intravenous contrast material injection showing a salt and pepper pattern [4]. Α quite useful technique is Susceptibility Weighted Imaging (SWI) which highlights in the area of the lesions the presence of prominent veins and T2*-hypointense curvilinear and/-or punctuate lesions of different size in the brainstem and cerebellum. Since T1-sequence with contrast medium does not reveal a corresponding dilatation of the veins, this phenomenon in the SWI sequence probably concerns the presence of a large amount of deoxyhemoglobin, possibly in the context of hypermetabolism [6]. Consequently, SWI sequence could be a useful technique for analysing the pathophysiology of CLIPPERS [6]. In conclusion, in cases where the described imaging pattern emerges, CLIPPERS syndrome should also be included in the differential diagnosis.