3.0T MR investigation of CLIPPERS: Role of susceptibility weighted and perfusion weighted imaging

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS): contemporary advances and current controversies

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is an inflammatory syndrome with characteristic clinical, radiological, and pathological features, and can be effectively treated with corticosteroid-based immunotherapies. The exact pathogenesis of CLIPPERS remains unclear, and specific diagnostic biomarkers are not available. According to the 2017 diagnostic criteria, probable CLIPPERS should be considered in middle-aged patients with subacute onset of pontocerebellar symptoms and typical punctuate and curvilinear gadolinium enhancement lesions ("salt-and-pepper" appearance) located in the hindbrain (especially pons) on magnetic resonance imaging. In addition, CLIPPERS-mimics, such as central nervous system (CNS) lymphoma, and several antibody-associated autoimmune CNS diseases (e.g., myelin oligodendrocyte glycoprotein antibody-associated disease, autoimmune glial fibrillary acidic protein astrocytopathy, and anti-N-methyl-D-aspartate receptor encephalitis), should be extensively excluded. The prerequisite for definite CLIPPERS is the perivascular T-cell-predominant inflammatory infiltration observed on pathological analysis. A biopsy is strongly suggested when clinical/radiological red flags are present. Most patients with CLIPPERS respond well to corticosteroids and have a good prognosis. Long-term low-dose corticosteroid maintenance therapy or corticosteroids coupled with immunosuppressants are recommended to prevent the recurrence of the syndrome. The potential progression of CLIPPERS to lymphoma has been suggested in some cases; therefore, at least 2-year clinical and radiological follow-up is essential. Here, we critically review the recent developments and provided an update on the clinical characteristics, diagnostic criteria, differential diagnoses, and therapeutic management of CLIPPERS. We also discuss the current controversies in this context that can be resolved in future research studies.

Clinical characteristics, management, and outcomes of CLIPPERS: A comprehensive systematic review of 140 patients from 100 studies

INTRODUCTION

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare inflammatory disorder of the central nervous system, characterized by symptoms referable to the brainstem and cerebellum such as, diplopia, gait ataxia and cerebellar dysarthria. The features and outcomes of CLIPPERS remains uncertain. we conducted this comprehensive systematic review to summarize all the existing studies that described CLIPPERS in the literature and to provide a quantitative assessment on the clinical characteristics, management, and outcomes of this rare syndrome.

METHODS

A comprehensive search of PubMed and Web of Science databases was conducted from inception until January 15, 2022, was conducted. We only included the cases that clearly reported probable or definite diagnosis of CLIPPERS based on Taieb et al.'s criteria. The quality of the included studies was assessed using the JBI Critical Appraisal Tool. Descriptive statistics were performed to analyze the studies. Data were expressed as mean and standard deviation (SD) for continuous variables and proportions for categorical variables.

RESULTS

We identified 100 case reports and series including a total of 140 patients with CLIPPERS (mean age: 46±18 years and males were 60%). The average follow-up duration was 32.27±57.8 months. Ataxia was the most common presenting symptom. Sixteen percent of the cases were associated with malignancy, mostly hematologic malignancies. The overall relapse rate was 59.2%, and the duration of steroid therapy was considerably shorter in the relapsed cases than in the non-relapsed (mean 6.19±7.9 vs. 10.14±12.1 days, respectively, P = 0.04). The overall mortality rate was 10%, but mortality in patients with malignancy was 30% and it was 12% in patients with relapses. In the case of steroid dosing (less than 20 mg/d versus greater than 20 mg/d) there was no significant modification in the risk of relapse.

CONCLUSION

CLIPPERS is a rare clinical syndrome that affects mainly middle-aged males. Diagnosis of CLIPPERS is often challenging, and delays in diagnosis and treatment can lead to unfavorable outcomes. Therefore, neurologists should maintain a high index of suspicion for CLIPPERS in any patient presenting with symptoms and signs referrable to the brainstem. These patients should be screened for associated malignancies, especially hematological malignancies. The cases associated with malignancy tend to have worse outcomes. The relapse rate is relatively high. The relapse rate may be associated with worse mortality. Based on our findings, we recommend that CLIPPERS be treated with high-dose steroid therapy for at least ten days during the acute phase with a very slow taper. Prospective studies with a larger sample size are needed to validate our findings and guide the clinical care of these patients.

CLIPPERS: Multiparametric and quantitative MRI features

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare chronic central-nervous-system inflammatory disorder that became known only recently, and the pathogenesis of CLIPPERS remains poorly understood. This report presents clinical and radiological features of a rare case: a young female patient who rapidly died of suspected CLIPPERS. Helpful multiparametric MRI diagnostic criteria are proposed that can help discriminate CLIPPERS from non-CLIPPERS pathologies. We reviewed clinical history, symptoms, quantitative data from brain multiparametric MRI before and after treatment, and histopathological data. Perfusion-weighted imaging revealed a decrease in regional cerebral blood flow by 31% and in cerebral blood volume by 64%, with a moderate increase in transit time and in time to peak by up to 23% in affected pontine and cerebral white matter. As estimated by diffusion tensor imaging, there was elevated density of tracts (n/mm²) and a decrease of fraction anisotropy (×10^-3 mm/s²) in the patient's pons as compared to a healthy control: density of tracts = 13.5 vs 12.4 and fraction anisotropy = 0.32 vs 0.45, respectively. Macromolecular proton fraction values proved to be reduced (15.8% and 14.5% in the control, respectively) in the patient's cerebral peduncles by 3% and in the pons by 4.1% and in a periventricular white matter lesion by 6.4% (11.3% in the normal-looking contralateral hemisphere). Based on our findings, we argue that quantitative MRI techniques may be a valuable source of biomarkers and reliable diagnostic criteria and can shed light on the pathogenesis and exact nosological position of this disorder.

CLIPPERS, chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids: A challenge in neurological practice, clinical landmarks (Review)

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a relatively newly discovered and characterized condition affecting the central nervous system (CNS) that involves the brainstem almost ubiquitously and that focuses primarily on the pons. Characteristically, CLIPPERS represents a combination of clinical symptoms related to the pathology of the brainstem in particular and has a characteristic appearance on magnetic resonance imaging (MRI), with punctate and curvilinear gadolinium enhancement 'peppering' the pons. The lesions can be viewed via neuroimaging with a predominance in the pons and adjacent rhombencephalic structures, such as the cerebellar peduncles, cerebellum, medulla, and middle brain. These lesions may also spread and appear in other areas of the brain such as the thalamus or white matter. As the name suggests, this clinical syndrome responds to immunosuppressive treatment based on glucocorticosteroids (GCSs), expressed as both clinical and radiological improvements. Support for this treatment is required for a long period, since exacerbations may occur without. Thus, the diagnosis of CLIPPERS has garnered increased attention from clinicians and the active exclusion of differential alternative diagnoses is needed. A specific biomarker of serum or cerebrospinal fluid (CSF) for this condition has not been discovered. The pathophysiology of this condition is not fully elucidated, and it is not yet clear whether CLIPPERS is a disease in its own right or is the culmination of several already known syndromes. Clinicians and radiologists should pay close attention to this condition as it is relatively easy to treat and patients can benefit from the early introduction of GCSs, which can produce significant results through long-term immunosuppression. Taking into account previous reports in the literature, which currently include over 50 cases reported as CLIPPERS, this analysis addressed the clinical features, and paraclinical and differential diagnoses of cases described in the literature.

Neuroimaging of Multiple Sclerosis Mimics

Multiple sclerosis (MS) is the most common immune-mediated disease of the central nervous system, characterized by demyelinating lesions of the brain and the spinal cord. Although it is extremely important to diagnose this condition in a timely manner, to initiate and monitor treatment to prevent permanent neurologic damage and disability, it is also necessary that other demyelinating conditions collectively referred to as MS mimics be identified and excluded. This article describes the in-depth neuroimaging characteristics and morphology of the pathologic lesions on the various neuroimaging modalities.

CLIPPERS and its mimics: evaluation of new criteria for the diagnosis of CLIPPERS

OBJECTIVE

To evaluate the accuracy of the recently proposed diagnostic criteria for chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS).

METHODS

We enrolled 42 patients with hindbrain punctate and/or linear enhancements (<3 mm in diameter) and tested the CLIPPERS criteria.

RESULTS

After a median follow-up of 50 months (IQR 25-82), 13 out of 42 patients were CLIPPERS-mimics: systemic and central nervous system lymphomas (n=7), primary central nervous system angiitis (n=4) and autoimmune gliopathies (n=2). The sensitivity and specificity of the CLIPPERS criteria were 93% and 69%, respectively. Nodular enhancement ( ≥ 3 mm in diameter), considered as a red flag in CLIPPERS criteria, was present in 4 out of 13 CLIPPERS-mimics but also in 2 out of 29 patients with CLIPPERS, explaining the lack of sensitivity. Four out of 13 CLIPPERS-mimics who initially met the CLIPPERS criteria displayed red flags at the second attack with a median time of 5.5 months (min 3, max 18), explaining the lack of specificity. One of these four patients had antimyelin oligodendrocyte glycoprotein antibodies, and the three remaining patients relapsed despite a daily dose of prednisone/prednisolone ≥ 30 mg and a biopsy targeting atypical enhancing lesions revealed a lymphoma.

CONCLUSIONS

Our study highlights that (1) nodular enhancement should be considered more as an unusual finding than a red flag excluding the diagnosis of CLIPPERS; (2) red flags may occur up to 18 months after disease onset; (3) as opposed to CLIPPERS-mimics, no relapse occurs when the daily dose of prednisone/prednisolone is ≥ 30 mg; and (4) brain biopsy should target an atypical enhancing lesion when non-invasive investigations remain inconclusive.

Case report with review of literature for the dilemma of diagnosis of CLIPPERS

CLIPPER is a chronic inflammatory disorder in the CNS, which is characterized by MRI appearance of punctate and curvilinear gadolinium enhancement that involve the pons and the cerebellum and exquisite response to steroid. We report a patient presented with clinical and radiological features suggestive of CLIPPERS. However, despite the initial response to steroid, there were dramatic changes in the course of his disease that were conducive to considering another diagnosis. We searched PubMed using word (CLIPPERS) till December 2018. The pathogenesis, clinical manifestations, imaging features, treatment and prognosis of this disorder are summarized. A review of the literature for cases of CLIPPERS demonstrated a subset of patients who later discovered to have an alternative pathology. Indeed, clinicians should be scrupulous to diagnose this disease based solely on the clinical and radiological findings and they should have a lower threshold of having a brain biopsy.

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) associated with or without lymphoma: Comparison of clinical features and risk factors suggestive of underlying lymphomas

BACKGROUND

We studied patients with chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) associated with or without lymphoma and measured risk factors suggestive of an underlying lymphoma and follow-up outcomes.

METHODS

CLIPPERS patients associated with or without lymphoma were included into this study. Clinical presentations were documented, risk factors suggestive of an underlying lymphoma were tested, and prognostic differences in terms of death were compared.

RESULTS

Ten patients had a diagnosis of CLIPPERS associated with lymphoma, with 6 B-cell non-Hodgkin lymphoma, 2 T-cell non-Hodgkin lymphoma and 2 Hodgkin lymphoma. Using multivariate logistic analysis, the following 3 independent risk factors were found to be related to a final diagnosis of lymphoma: hyperreflexia (HR 16.56; 95% CI 1.03-265.29; p = 0.032), elevated protein in CSF (HR 11.59; 95% CI 1.24-108.39; p = 0.047), and recurrences between 2 months and 1 year after treatment (HR 29.27; 95% CI 2.09-409.58; p = 0.012). The model calibration was satisfactory (p = 0.392 with the Hosmer-Lemeshow test), and the discrimination power was good (area under the receiver operating characteristic curve 0.921; p < 0.001, 95% CI 0.826-1.000). Patients with CLIPPERS associated with lymphoma had higher mortality rate and lymphoma was a significant predictor of total mortality (HR 0.040; 95% CI 0.006-0.262; p = 0.001).

CONCLUSIONS

Hyperreflexia, elevated protein in CSF and recurrences between 2 months and 1 year after treatment are risk factors suggesting an underlying lymphoma. Relapses during high-dose steroids maintenance therapy can be indicative of lymphoma, too. Patients having CLIPPERS associated with lymphoma have a worse prognosis than those without lymphoma.

Misdiagnosis: CNS Erdheim-Chester disease mimicking CLIPPERS

Introduction Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is an inflammatory central nervous system (CNS) disorder with particular involvement of the pons. Diagnostic criteria include a range of clinical symptoms related to the underlying brainstem pathology, visible with magnetic resonance imaging (MRI). MRI findings include the appearance of punctuate and curvilinear gadolinium enhancement 'peppering' the pons. We discuss a patient presenting with clinical and radiographic characteristics of CLIPPERS who was diagnosed with Erdheim-Chester disease (ECD). Case report A 52-year-old male presented with 2 years of progressive spasticity, dysarthria, and gait instability. Initially, he was diagnosed with Parkinson's disease at an outside hospital, based on tremor, rigidity, and gait instability; however, he failed to improve with a trial of levodopa. Brain MRI showed small enhancing parenchymal nodules coalescing in the central pons, but also affecting the cerebellum and cerebellar peduncles, with more punctate enhancing lesions in the cerebral lobar subcortical white matter. When the patient's response to steroids was inadequate, further imaging was done, revealing perinephric processes. Subsequent biopsy revealed ECD. Conclusions A review of the literature for cases of CLIPPERS demonstrated a subset of patients later found to have various malignancies involving the CNS. This case report uses the patient's unique radiographic and clinical presentation to demonstrate the importance of the exclusion criteria within the CLIPPERS diagnostic requirements and stresses red flags suggestive of alternative diagnoses. This distinction is of high importance when differentiating a relatively benign process such as CLIPPERS from more malignant diseases.

Horizontal eyeball akinesia as an initial manifestation of CLIPPERS: Case report and review of literature

BACKGROUND

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare chronic inflammatory disorder in the central nervous system (CNS), which is characterized by magnetic resonance imaging (MRI) appearance with punctate and curvilinear gadolinium enhancement "peppering" the pons. Lesions of CLIPPERS mainly involve the pons and the cerebellum. Adjacent structures such as the medulla and the midbrain may also be involved. It is proposed that CLIPPERS is an immune-mediated inflammatory condition characteristic of T-cell-predominant infiltrates and good responsiveness to corticosteroids.

METHODS AND RESULTS

We report a 46-year-old woman who presented with horizontal eyeball akinesia and gait ataxia with characteristic MRI features of CLIPPERS. The possible pathogenesis, clinical manifestations, imaging features, treatment, and prognosis of this peculiar disorder are summarized.

CONCLUSION

This report contributes to the clinical understanding of CLIPPERS which may present with horizontal eyeball akinesia as an initial manifestation. The characteristic presentation of a subacute cerebellar and brainstem syndrome and pepper-like gadolinium enhancement was confirmed in this report. Long-term immunosuppressive treatment seems to be mandatory to sustain improvement. Azathioprine alone may be capable of maintaining remission.

Susceptibility-weighted imaging in parenchymal neurosyphilis: identification of a new MRI finding

BACKGROUND

General paresis (GP) is a late form of parenchymal neurosyphilis causing dementia and neuropsychiatric disorders. The diagnosis is often difficult since the clinical signs are protean. So far, neuroimaging has played a minor role as radiological findings are not specific.

METHODS

We studied three immunocompetent patients, admitted to hospital for cognitive impairment. The diagnosis of neurosyphilis was formulated on the basis of serological texts and cerebrospinal fluid analysis. The patients underwent a 3 T MR examination including susceptibility-weighted imaging (SWI) sequence before and after the initiation of penicillin therapy.

RESULTS

In all patients, SWI revealed cortical hypointensity, mostly distributed in frontal and temporal lobes. In drug-naive patients, the hypointensity extended over the whole cortical thickness, from the cortical/subcortical junction to the pial surface. After starting the penicillin therapy, the cortical hypointensity partially reversed, involving only the deep cortical layers.

CONCLUSIONS

The MRI pattern at SWI observed in patients with GP was not reported in other infectious or inflammatory disease of the central nervous system, thus we suggest it could be a peculiar radiological finding of the disease. On the basis of previous pathological data, we hypothesise that cortical SWI hypointensity could be expression of iron deposits within activated microglia.

CLIPPERS: chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids. Review of an increasingly recognized entity within the spectrum of inflammatory central nervous system disorders

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a recently defined inflammatory central nervous system (CNS) disorder, prominently involving the brainstem and in particular the pons. The condition features a combination of clinical symptoms essentially referable to brainstem pathology and a characteristic magnetic resonance imaging (MRI) appearance with punctate and curvilinear gadolinium enhancement 'peppering' the pons. The radiological distribution is focused in the pons and adjacent rhombencephalic structures such as the cerebellar peduncles, cerebellum, medulla and the midbrain. While the lesion burden with a perivascular pattern is typically most dense in these pontine and peripontine regions, enhancing lesions may additionally extend into the spinal cord and supratentorial structures such as the thalamus, basal ganglia, capsula interna, corpus callosum and the cerebral white matter. Another core feature is clinical and radiological responsiveness to glucocorticosteroid (GCS)-based immunosuppression. As withdrawal of GCS treatment results commonly in disease exacerbation, long-term immunosuppressive therapy appears to be mandatory for sustained improvement. Diagnosis of CLIPPERS is challenging, and requires careful exclusion of alternative diagnoses. A specific serum or cerebrospinal fluid (CSF) biomarker for the disorder is currently not known. Pathogenesis of CLIPPERS remains poorly understood, and the nosological position of CLIPPERS has still to be established. Whether CLIPPERS represents an independent, actual new disorder or a syndrome that includes aetiologically heterogeneous diseases and/or their prestages remains a debated and not finally clarified issue. Clinicians and radiologists should be aware of this condition and its differential diagnoses, given that CLIPPERS constitutes a treatable condition and that patients may benefit from an early introduction of GCS ensued by long-term immunosuppression. Based on previous reports in literature - currently encompassing more than 50 reported cases of CLIPPERS - this review addresses clinical features, diagnostic criteria, differential diagnoses and therapeutic management of this peculiar disorder.