Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids with a Significant Elevation of β-2 Microglobulin Levels

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.

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.