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

Extensive brainstem lesions in myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD): A case report

Myelin oligodendrocyte glycoprotein antibody-associated disease is a group of central nervous system demyelinating disorders caused by autoantibodies. While myelin oligodendrocyte glycoprotein antibody-associated disease typically presents as optic neuritis and myelitis in adults, this case report details a patient with brainstem lesions. A 45-year-old male presented with episodes of vertigo, nystagmus, and diplopia in left lateral gaze, which had persisted for 2 months, accompanied by headache. Computed tomography showed hyperdensity extending from the left side of the pons to the middle cerebellar peduncle. Magnetic resonance imaging revealed lesions exhibiting heterogeneous diffusion restriction, with enhancement that included granular and linear patterns. 18F-fluorodeoxyglucose positron emission tomography demonstrated increased uptake in these lesions. Following further evaluation, myelin oligodendrocyte glycoprotein antibody-associated disease was diagnosed. Treatment with high-dose corticosteroids initially alleviated symptoms, but symptoms flared upon reduction of the steroids. This case underscores the importance of considering myelin oligodendrocyte glycoprotein antibody-associated disease in the differential diagnosis of brainstem lesions and discusses distinguishing imaging features from similar conditions.

Unusual CLIPPERS presentation with a predominant spinal cord involvement: case report and review of the literature

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a discrete nosological entity characterized by punctate and curvilinear gadolinium enhancement "peppering" the pons and a strong response to steroids. MRI images typically show pontine and cerebellar punctate-enhancing lesions, which occasionally spread up to the juxtacortical areas and down to the spinal cord. Interestingly, the more distant the lesion is from the pons, the less intense they become. Herein, we describe an extremely rare case of CLIPPERS presenting with predominant spinal cord involvement; then, we searched in the literature the available cases with a similar presentation. Our case focuses attention on a rare MRI CLIPPERS presentation. Since CLIPPERS has a dramatic response to corticosteroid treatment, it is fundamental to promptly recognize its MRI pattern to start treatment as soon as possible.

18 F-FDG Brain PET/MRI in Chronic Lymphocytic Inflammation With Pontine Perivascular Enhancement Responsive to Steroids

ABSTRACT

An 89-year-old man presented with progressive gait disturbance, diplopia, and ataxia. Initial brain MRI demonstrated T2/FLAIR hyperintense signal abnormality in the pons extending along the middle cerebellar peduncles into the cerebellum, with associated punctate, patchy, and linear enhancement on postcontrast imaging. Initially, this was attributed to brainstem encephalitis; however, sarcoidosis, histiocytosis, and paraneoplastic/autoimmune encephalitis remained on the differential. One month after initial MRI, 18 F-FDG brain PET/MRI was performed and showed marked pontine hypermetabolism corresponding to the signal abnormality and enhancement on structural imaging. Collectively, these findings are characteristic of chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids.

Headache As the Sole Symptom in Chronic Lymphocytic Inflammation With Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS): A Case Report and Literature Review

Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS) is a rare central nervous system inflammatory condition usually presenting with a range of symptoms, including ataxia, diplopia, dysarthria, seizures, and headaches. We present a unique case of a 22-year-old woman exhibiting headache as the sole symptom. Imaging and biopsy confirmed the diagnosis, and initial steroid treatment provided relief, though it relapsed on tapering. Long-term management with low-dose steroids and mycophenolate mofetil achieved remission. This case highlights the importance of recognizing atypical presentations of CLIPPERS, emphasizing the need for prompt diagnosis and appropriate treatment plans to improve patient outcomes. Further research is necessary to enhance our understanding and management of CLIPPERS.

Uncommon and Miscellaneous Inflammatory Disorders of the Brain and Spine

Inflammatory disorders of the brain and spine have a highly variable MRI appearance, often demonstrating significant overlap in imaging features. The resulting diagnostic dilemma is particularly challenging when considering the more uncommon neuroinflammatory entities. Diligent examination of the salient clinical presentation and signal alteration on imaging examination is necessary when considering neuroinflammation as a diagnostic possibility and may aid in raising suspicion for a particular neuroinflammatory entity. This article reviews a selection of uncommon and miscellaneous inflammatory disorders of the brain and spine to raise awareness of the clinical and imaging features that may assist in this challenging diagnostic task.

Clinicoradiological features of probable chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) syndrome

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a recently described chronic inflammatory central nervous system disease. This case report describes a young female patient presenting with weakness in bilateral upper and lower limbs and tinnitus for 2 months. A neurological examination revealed signs of brainstem and cerebellar involvement. MRI brain showed characteristic features of CLIPPERS, with punctate and nodular enhancement in the pons and cerebellum. Differential diagnoses were systematically considered and excluded. The patient showed significant clinical and radiological improvement with steroid therapy. No clinical or radiological red flags occurred during the follow-up. This case underscores the critical role of integrating clinical and radiological findings to effectively diagnose and manage CLIPPERS. It emphasises the importance of ruling out alternative diagnoses through a thorough evaluation.

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.

Anything but Little: a Pictorial Review on Anatomy and Pathology of the Cerebellum

Despite its small size the cerebellum is an anatomically complex and functionally important part of the brain. Traditionally the cerebellum is viewed as a motor control structure entirely devoted to motor control and learning, but recent functional magnetic resonance imaging (fMRI) studies demonstrated significant involvement of the cerebellum in higher order cognitive functions. The anatomical complexity of the cerebellum is reflected by the several nomenclature systems that exist for the description of cerebellar anatomy. The cerebellum can be affected by a variety of pathological processes, including congenital, infectious and inflammatory, neoplastic, vascular, degenerative and toxic metabolic diseases. The purpose of this pictorial review is to (1) provide a general overview of cerebellar anatomy and function, (2) demonstrate normal cerebellar anatomy on imaging studies, and (3) illustrate both common as well as rare pathological conditions affecting the cerebellum.

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) syndrome: Treatment approach depends on disease course

INTRODUCTION

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare inflammatory central nervous system (CNS) disorder, chiefly involving the brainstem, especially the pons. The diagnosis is challenging, requires careful exclusion of alternative diagnoses and a targeted therapeutic approach. CLIPPERS is known to respond well to corticosteroids, but the treatment needs to be long-term and can cause significant side-effects. Moreover, subsequent corticosteroid withdrawal often leads to a relapse. It has been suggested that anti-CD20 molecules could benefit several antibody-mediated CNS inflammatory diseases, including CLIPPERS.

CASE REPORT

This paper describes two cases of CLIPPERS. The first demonstrates the benefit of early introduction of corticosteroids with side effects in cases of long-term use. The second demonstrates the efficacy of ocrelizumab (anti-CD20 molecule) in a severe course of CLIPPERS.

CONCLUSION

These two cases bring attention to this rare, often misdiagnosed but treatable disease.

A Case of Radiologically Compatible Chronic Lymphocytic Inflammation With Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS) With Demyelinating Lesions

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a recently identified diagnosis that can cause a variety of severe symptoms, including ataxia, dysarthria, diplopia, paraparesis, and vertigo. These symptoms rarely present in isolation but often accompany one another in various combinations. Magnetic Resonance Imaging (MRI) of the brain is critical for making the diagnosis and typically reveals scattered enhancement within the pons and adjacent structures. The syndrome responds well to high-dose steroids, and maintenance therapy is required to prevent a recurrence. In this report, we present a case of a 62-year-old man who developed CLIPPERS syndrome. The patient presented with hemiparesis and dysarthria, which developed over four months and then acutely worsened within 24 hours. After diagnosing CLIPPERS, the patient was placed on high-dose steroids and experienced rapid clinical improvement, as well as improvement on repeat MRI. The patient's treatment was complicated by an incidental diagnosis of tuberculosis, which required simultaneous management with isoniazid.

The Elusive SLIPPERS Syndrome (Supratentorial Lymphocytic Inflammation with Parenchymal Perivascular Enhancement Responsive to Steroids): A Case Report and Literature Review

Background

In 2015, the term "SLIPPERS" was created to refer to a rare type of encephalomyelitis called CLIPPERS syndrome that affects the pons and sometimes other nearby structures, but in this case, it primarily affects the supratentorial region. This variation of the condition is responsive to treatment with steroids.

Case Description

We report the case of a patient who presented with seizures and visual field deficit and had typical radiological and histopathological characteristics of SLIPPERS syndrome.

Conclusion

Although the literature is inundated with CLIPPERS syndrome, its supratentorial variant is extremely rare. To our knowledge, this is fourth case of SLIPPERS syndrome to be reported in literature and serves to enhance clinicopathological understanding of this elusive entity.

Relapsing Encephalomyelitis After COVID-19 Infection and Vaccination: From the National MS Society Case Conference Proceedings

Prior case studies suggest that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its vaccines may unmask CNS neuroinflammatory conditions. We present a case of relapsing steroid-responsive encephalomyelitis after SARS-CoV-2 infection and subsequent COVID-19 vaccination. We also characterize the frequency of CNS neuroinflammatory events reported in the literature after both SARS-CoV-2 infection and COVID-19 vaccination.

Current Updates on the Diagnosis and Management of Multiple Sclerosis for the General Neurologist

Multiple sclerosis (MS) is an immune-driven disease that affects the central nervous system and is characterized by acute-on-chronic demyelination attacks. It is a major cause of global neurological disability, and its prevalence has increased in the United States. Conceptual understandings of MS have evolved over time, including the identification of B cells as key factors in its pathophysiology. The foundation of MS management involves preventing flares so as to avoid long-term functional decline. Treatments may be categorized into low-, middle-, and high-efficacy medications based on their efficacy in relapse prevention. With 24 FDA-approved treatments for MS, individual therapy is chosen based on distinct mechanisms and potential side effects. This review provides a detailed update on the epidemiology, diagnosis, treatment advances, and major ongoing research investigations in MS.

The pathogenesis hypothesis and research progress of CLIPPERS: A literature review

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is still a rare autoimmune disease in the world. In recent years, there are more and more reports about the clinical manifestations of CLIPPERS, but the specific etiology and pathogenesis are not clear. In this paper, by collating the literature reported in recent years, in the reported effective treatment cases, we found the current hypothesis about the pathogenesis of CLIPPERS. Three pathogenesis hypotheses: organ-specific autoimmunity; virus infection affects autoimmunity; and helper T lymphocyte 17 mediates autoimmunity. Although it is hypothetical, it is expected to further clarify the pathogenesis, evolution characteristics, and treatment of CLIPPERS, so as to provide a reference for further understanding of the disease. In the future, more observations and studies are needed to further verify the feasibility of the hypothesis. This article expands on atypical clinical manifestations and summarizes treatment options. Hope to provide a reference for clinical diagnosis and treatment of CLIPPERS.

Spectrum of Autoimmune Diseases—Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS)—Clinical Case

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) syndrome is a rare inflammatory disease of an undetermined aetiology. The condition is characterised by a range of clinical manifestations generally associated with damage to brainstem structures, the cerebellum, with characteristic magnetic resonance imaging (MRI) findings. The main feature is a good clinical and radiological response to glucocorticosteroid (GCS)-based immunosuppressive treatment. The diagnosis of CLIPPERS is difficult and requires extensive differential diagnosis. A specific biomarker in serum or cerebrospinal fluid (CSF) for this disorder is currently unknown. The pathogenesis of CLIPPERS remains poorly understood and its nosological position has not yet been established. Whether CLIPPERS represents an independent, genuine new disorder or a syndrome in the course of diseases with heterogeneous aetiology and/or their precursor stages remains debatable and incompletely clarified. We present a case report of a patient who was diagnosed with CLIPPERS syndrome on the basis of her clinical and radiological features and by performing an extensive differential diagnosis. The patient has been under neurological follow-up for five years.

CLIPPERS Syndrome After Vaccination. An Unusual ASIA Presentation

The chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) and autoimmune/inflammatory syndrome induced by adjuvants (ASIA) were described a decade ago. There are a limited number of reports and these diseases are still underdiagnosed. We presented a 35 years-old patient with clinical manifestations of cerebellum affection and enhancement in the MRI, with the influenza vaccine as the only triggering factor. Infectious diseases, malignancy, and additional systemic involvement were ruled out; therefore, on suspicion of CLIPPERS syndrome, the patient received corticosteroid therapy with an adequate response. The knowledge of CLIPPERS syndrome as an unusual ASIA presentation and high response to the corticosteroids may lead to a timely diagnosis, appropriate treatment, and follow up with better outcomes for patients.

Efficacy of Intravenous Immunoglobulins against Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids: A Case Report

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is an inflammatory disease of the central nervous system that predominantly affects the brainstem. Apart from corticosteroids, there are few reported treatment options for CLIPPERS, and there is no standard therapy. A 77-year-old man presented with diplopia that had persisted for 5 months. Dysarthria and numbness of the distal right upper extremity and right lips were also observed. Brain magnetic resonance imaging (MRI) revealed a hyperintense area around the brainstem. Symptoms were relieved immediately following intravenous methylprednisolone (IVMP) administration. However, after gradual tapering of oral prednisolone to 5 mg/day, the symptoms relapsed, and brain imaging revealed that the condition had worsened. Intravenous immunoglobulins (IVIg) were administered for recurrence, with no clinical improvement. After each IVMP treatment, the patient recovered promptly. Based on the patient's symptoms and characteristic MRI findings, exclusion of other diseases, and the significant efficacy of corticosteroids, he was diagnosed with CLIPPERS. There was no recurrence at a maintenance prednisolone dose of 8 mg/day. IVIg had a poor effect on the acute phase of CLIPPERS symptoms. Compared with other immunosuppressants, IVIg is less effective in suppressing the relapse of CLIPPERS.

CLIPPERS Responsive to Cladribine as a Durable Steroid-Sparing Agent

Objective

We report a case of chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) who achieved durable and steroid-free remission after IV cladribine.

Methods

A 25 year-old man presented with progressively worsening headaches, polydipsia, dysarthria, diplopia and vertigo, and obtundation requiring respiratory support. CSF revealed lymphocytosis, and MRI revealed a perivascular pattern of punctate enhancement involving the pons. An extensive workup for inflammatory, autoimmune, infective, and malignant explanations was unrevealing. He responded dramatically to steroids, compatible with CLIPPERS as a diagnosis of exclusion. Attempts to wean prednisone over the ensuing year resulted in 2 clinical relapses and persistent punctate enhancement. Given significant steroid side effects, steroid-sparing agents were considered.

Results

IV cladribine IV (0.0875 mg/kg adjusted body weight daily × 4 days at 0, 4, 8, and 16 months) was selected, given its favorable side effect profile including lower risks of malignancy and infertility and the potential for long-lasting effects. The only side effect was short-term fatigue at the time of infusion. At 20 months after cladribine initiation, he was able to wean-off prednisone altogether. Now at 33 months, he remains in clinical and MRI remission.

Discussion

Cladribine is a rational candidate steroid-sparing treatment for presumed neurologic autoimmune conditions such as CLIPPERS.

Classification of Evidence

This study provides Class IV evidence that cladribine is a steroid-sparing treatment consideration in CLIPPERS.

The role of MRI in the early diagnosis of chronic lymphocytic inflammation (CLIPPERS syndrome)

ABSTRACT Background. Chronic lymphocytic inflammation with perivascular contrast enhancement in the pons responsive to steroids (CLIPPERS) is a rare and relatively "new" pathology and MRI is highly important in its diagnosis. Clinical Case Description. Chronic lymphocytic inflammation with perivascular contrast enhancement in the pons responsive to steroids (CLIPPERS) is a rare and relatively "new" pathology and MRI is highly important in its diagnosis. Conclusion. MRI not only enables high-quality neuroimaging of CLIPPERS, it also allows avoiding invasive, traumatic diagnostic methods.

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.

Rare Etiologies in Immune-Mediated Cerebellar Ataxias: Diagnostic Challenges

The cerebellum is particularly enriched in antigens and represents a vulnerable target to immune attacks. Immune-mediated cerebellar ataxias (IMCAs) have diverse etiologies, such as gluten ataxia (GA), post-infectious cerebellitis (PIC), Miller Fisher syndrome (MFS), paraneoplastic cerebellar degeneration (PCD), opsoclonus myoclonus syndrome (OMS), and anti-GAD ataxia. Apart from these well-established entities, cerebellar ataxia (CA) occurs also in association with autoimmunity against ion channels and related proteins, synaptic adhesion/organizing proteins, transmitter receptors, glial cells, as well as the brainstem antigens. Most of these conditions manifest diverse neurological clinical features, with CAs being one of the main clinical phenotypes. The term primary autoimmune cerebellar ataxia (PACA) refers to ataxic conditions suspected to be autoimmune even in the absence of specific well-characterized pathogenic antibody markers. We review advances in the field of IMCAs and propose a clinical approach for the understanding and diagnosis of IMCAs, focusing on rare etiologies which are likely underdiagnosed. The frontiers of PACA are discussed. The identification of rare immune ataxias is of importance since they are potentially treatable and may lead to a severe clinical syndrome in absence of early therapy.

Case 302: Supratentorial Lymphocytic Inflammation with Parenchymal Perivascular Enhancement Responsive to Steroids

HISTORY

Part one of this case appeared 4 months previously and may contain larger images. A 21-year-old immunocompetent man who was a long-term resident of Qatar presented to the emergency department with recurrent episodes of unprovoked generalized tonic-clonic seizures lasting 2-3 minutes that spontaneously resolved and were associated with postictal confusion. The patient also had progressive mild diplopia, intermittent dizziness, and numbness in the left arm over the course of 3 months. The patient did not have any other systemic symptoms or chronic medical diseases. He did not have any history of intake of illicit drugs, supplements, or regular medications; he had not received any recent vaccinations; and he had not undergone any surgical procedures. He had no history of travel. At presentation, vital signs were normal. Neurologic examination showed mild left homonymous hemianopia, normal gait with no cerebellar signs, and preserved sensations, power, tone, and reflexes in all four limbs. An electroencephalogram showed no epileptiform discharges. Chest CT and extensive laboratory work-up, including viral, fungal, bacterial, and parasite work-up, thyroid function tests, and immunologic blood tests yielded normal results. Those included normal complete and differential blood counts and normal serum chemistry. Serum analysis was negative for antinuclear antibody, Sjögren syndrome antigens A and B, cytoplasmic antineutrophil cvtoplasmic antibody, and paraneoplastic profile. Serum evaluation was also negative for human immunodeficiency virus type 1 and type 2 RNA, and Brucella, Schistosoma, and toxoplasma antibodies. Venereal Disease Research Laboratory (VDRL) and rapid plasma regain (RPR) test results were negative. Cerebrospinal fluid (CSF) analysis revealed clear fluid and normal pressure and biochemistry, except for elevated protein concentration (0.48 g/L) (normal range, 0.15-0.45 g/L). There were 43 leukocytes/µL (99% lymphocytes) (normal range, 0-5 leukocytes/µL; lymphocytes range, 40%-80%), with no atypical or malignant cells. CSF Gram staining, acid-fast staining, cryptococcal antigen, varicella-zoster virus polymerase chain reaction (PCR), herpes simplex virus PCR, VDRL, and RPR test results were negative. CSF cultures did not show any evidence of growth of bacteria, fungi, or acid-fast bacillus. CSF flow cytometry did not show a monoclonal lymphoid population. No CSF oligoclonal bands were detected. Conventional brain MRI with intravenous administration of contrast material and perfusion study were performed and included different sequences (Figs 1-3).

Magnetic Resonance Imaging of Autoimmune Demyelinating Diseases as a Diagnostic Challenge for Radiologists: Report of Two Cases and Literature Review

The magnetic resonance characteristics of autoimmune demyelinating diseases are complex and represent a challenge for the radiologist. In this study we presented two different cases of detected autoimmune demyelinating diseases: one case of acute disseminated encephalomyelitis and one case of neuromyelitis optica, respectively. Expected and unexpected findings of magnetic resonance imaging examination for autoimmune demyelinating diseases were reported in order to provide a valuable approach for diagnosis. In particular, we highlight, review and discuss the presence of several uncommon imaging findings which could lead to a misinterpretation. The integration of magnetic resonance imaging findings with clinical and laboratory data is necessary to provide a valuable diagnosis.

Chronic Lymphocytic Inflammation With Pontine Perivascular Enhancement Responsive to Steroids: An Acute Presentation

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare disease with an unknown etiology which most commonly results in subacute diplopia and ataxia. Diagnosis is achieved through a triad of the following findings: lymphocytic pleocytosis with increased CD4+ T cells on cerebrospinal fluid (CSF) analysis; perivascular punctate and curvilinear hemorrhages in the pons, medulla, or cerebellum on magnetic resonance imaging (MRI) with contrast; and the cessation of symptoms after the initiation of corticosteroids. Here, we report the case of a 23-year-old male who presented with non-specific signs and symptoms, including diffuse weakness in all limbs, ataxia, and slurred speech. The diagnosis was achieved through a contrast MRI of the brain, suggestive of brainstem encephalitis, and a CSF analysis, which revealed elevated glucose and protein levels. Intravenous methylprednisolone was administered for five days and resulted in acute improvement of the patient’s clinical status. Repeat CSF analysis and MRI of the brain with contrast two weeks later showed resolution of previous findings. CLIPPERS syndrome is a newly identified disease thought to cause a predominantly inflammatory reaction in the pons, medulla, cerebellum, and supratentorial region. MRI with contrast tends to reveal a “salt and pepper appearance” in a punctate and curvilinear fashion. The hallmark of treatment is corticosteroid therapy, and discontinuation of therapy should be done with caution as relapse of the syndrome with corticosteroid withdrawal has been documented.

Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids May Extend above and below Pons and Is Associated with Other Autoimmune Diseases

Many autoimmune diseases can affect the central nervous system, and their varying clinical presentations often confound a straightforward diagnosis. In this report, we describe a unique presentation of CLIPPERS syndrome. To our knowledge, this is the first case to demonstrate significant supratentorial involvement with symmetric and non-confluent lesions in the medial orbitofrontal cortex; additionally, this is the second case to describe an association between diagnoses of hypothyroidism and CLIPPERS.

Autopsy Case of Meningoencephalomyelitis Associated With Glial Fibrillary Acidic Protein Antibody

BACKGROUND AND OBJECTIVES

To describe the autopsy findings and neuropathologic evaluation of autoimmune meningoencephalomyelitis associated with glial fibrillary acidic protein (GFAP) antibody.

METHODS

We reviewed the clinical course, imaging, laboratory, and autopsy findings of a patient with autoimmune meningoencephalomyelitis associated with GFAP antibody who had a refractory course to multiple immunosuppressive therapies.

RESULTS

The patient was a 70-year-old man who was diagnosed as GFAP antibody-associated autoimmune meningoencephalomyelitis. MRI of the head showed linear perivascular enhancement in the midbrain and the basal ganglia. Despite treatment with high-dose corticosteroids, plasma exchange, IV immunoglobulins, and cyclophosphamide, he died with devastating neurologic complications. Autopsy revealed a coexistent neuroendocrine tumor in the small intestine and diffuse inflammation in the brain parenchyma, perivascular spaces, and leptomeninges, with predominant T-cells, macrophages, and activated microglia. B-cells and plasma cells were absent. There was no astrocyte involvement with change in GFAP immunostaining.

DISCUSSION

This case illustrates autoimmune meningoencephalomyelitis associated with GFAP antibody in the CSF and coexistent neuroendocrine tumor. The autopsy findings were nonspecific and did not demonstrate astrocyte involvement. Further accumulation of cases is warranted to delineate the utility and pathogenic significance of the GFAP autoantibody.

Cerebral Microvascular Erdheim-Chester Disease: A Perivascular Hematopoietic Vasculopathy

Erdheim-Chester disease (ECD) is a rare and elusive hematopoietic malignancy that may involve the nervous system in various ways. Cerebrovascular ECD involves the perivascular infiltration and compromise of any cervicocranial vessel by transformed proliferating histiocytes. Presented is the novel case of a patient with pathologically proven perivascular microangiopathy, manifesting in multifaceted fashion with ischemia, hemorrhage, mass lesions, and edema.

CLIPPERS associated with hypersensitivity pneumonitis: a case report

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare and poorly understood pathology. In this case report we present a 51-year-old male that presented with neurological deficits with recent hypersensitivity pneumonitis. Imaging studies showed multiple punctate enhancing lesions involving the brainstem. After initiation of corticosteroids his symptoms improved, with a decrease in size of his lesions 6-months after his initial presentation. Due to its misdiagnosis, we propose the use of diagnostic criteria, described on this case report, for prompt treatment to avoid neurological sequelae.

Autoimmune Brainstem Encephalitis: An Illustrative Case and a Review of the Literature

Autoimmune brainstem encephalitis (BSE) is a rare neurological condition with a wide range of underlying etiologies. It can be subdivided into two broad groups: a primary inflammatory disease of the central nervous system (CNS) or a brainstem disorder secondary to systemic diseases where the CNS is only one of many affected organs. Symptoms range from mild to life-threatening manifestations. Most cases respond well to immunotherapy. Therefore, broad and in-depth knowledge of the various inflammatory disorders that target the brainstem is essential for guiding the diagnostic approach and assisting in early initiation of appropriate therapy. We herein report on a case of BSE and provide an overview of the various causes of autoimmune BSE with an emphasis on the clinical manifestations and diagnostic approach.

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids, a mimicker of malignancy: a case report and review of the literature

Background

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids is a clinically and radiographically distinct inflammatory syndrome affecting multiple structures of the brain, including the cerebellum, brainstem, and spinal cord. The clinical presentation can be variable, including ataxia, nystagmus, dysarthria, dysphagia, and other subacute brainstem, cranial nerve, or cerebellar symptoms. These symptoms can be subacute to chronic, episodic, and progressive, making the diagnosis challenging. The hallmark radiographic magnetic resonance imaging findings are gadolinium-enhancing punctate lesions predominantly “peppering” the pons in a perivascular pattern.

Case presentation

Here, we describe a case and literature review of a 74-year-old Caucasian male who presented with subacute symptoms of ataxia, diplopia, and generalized fatigue. Physical examination was notable for horizontal nystagmus and wide-based gait. Magnetic resonance imaging revealed angiocentric enhancement predominantly in the brainstem and cerebellum, with involvement of the basal ganglia, thalami, and supratentorial white matter. Meanwhile, a screening computed tomography scan demonstrated a right upper lobe mass with biopsy proving primary lung cancer. Biopsy of one of the brain lesions showed perivascular infiltrate primarily composed of CD3+ T cells, scattered CD20+ B cells, and no signs of malignancy. The patient was started on high-dose glucocorticoids followed by a maintenance regimen with rapid improvement clinically and radiographically. Given extensive work-up was negative, these clinical and radiographic findings were consistent with chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids.

Conclusions

This case illustrates the difficulty of diagnosing chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids, given its variable presentation, lack of specific laboratory findings, and poorly understood pathogenesis. We demonstrate a case that responded well to oral corticosteroid burst followed by a taper to the lowest corticosteroid dose clinically possible. Failure to recognize this syndrome could result in permanent central nervous system morbidity. Therefore, earlier recognition is crucial for this treatable condition.

Relapsing Bickerstaff Brainstem Encephalitis After Autologous Stem Cell Transplant

Bickerstaff brainstem encephalitis, widely considered to be associated with Miller Fisher and Guillain-Barré syndromes, is a rare disease state defined by the triad of ophthalmoplegia, ataxia, and decreased consciousness. The presence of central nervous system involvement, commonly in the form of impaired arousal, solidifies it as a unique entity. We present a case of this rare syndrome after autologous stem cell transplant.

Hemophagocytic Lymphohistiocytosis Gene Mutations in Adult Patients Presenting With CLIPPERS-Like Syndrome

Objective

To determine whether adult cases of Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS) may be related to familial hemophagocytic lymphohistiocytosis (HLH) causes, we have screened patients with adult-onset CLIPPERS for mutations in primary HLH-associated genes.

Methods

In our cohort of 36 patients fulfilling the criteria for probable or definite CLIPPERS according to the CLIPPERS-2017 criteria, we conducted a first study on 12 patients who consented to genetic testing. In these 12 patients, systemic HLH criteria were searched, and genetic analysis of 8 genes involved in primary HLH was performed.

Results

Four definite and 8 probable CLIPPERS were enrolled (n = 12). Mutations involved in HLH were identified in 2 definite and 2 probable CLIPPERS (4/12). Three of them had biallelic PRF1 mutations with reduced perforin expression in natural killer cells. The remaining patient had biallelic UNC13D mutations with cytotoxic lymphocyte impaired degranulation. None of the mutated patients reached the criteria for systemic HLH. During follow-up, 3 of them displayed atypical findings for CLIPPERS, including emergence of systemic non-Hodgkin lymphoma (1/3) and confluent gadolinium-enhancing lesions on brain MRI (3/3).

Conclusions

In our patients presenting with adult-onset CLIPPERS, one-third have HLH gene mutations. This genetic treatable condition should be searched in patients with CLIPPERS, especially in those presenting with atypical findings.

Immune-Mediated Cerebellar Ataxias: Clinical Diagnosis and Treatment Based on Immunological and Physiological Mechanisms

Since the first description of immune-mediated cerebellar ataxias (IMCAs) by Charcot in 1868, several milestones have been reached in our understanding of this group of neurological disorders. IMCAs have diverse etiologies, such as gluten ataxia, postinfectious cerebellitis, paraneoplastic cerebellar degeneration, opsoclonus myoclonus syndrome, anti-GAD ataxia, and primary autoimmune cerebellar ataxia. The cerebellum, a vulnerable autoimmune target of the nervous system, has remarkable capacities (collectively known as the cerebellar reserve, closely linked to plasticity) to compensate and restore function following various pathological insults. Therefore, good prognosis is expected when immune-mediated therapeutic interventions are delivered during early stages when the cerebellar reserve can be preserved. However, some types of IMCAs show poor responses to immunotherapies, even if such therapies are introduced at an early stage. Thus, further research is needed to enhance our understanding of the autoimmune mechanisms underlying IMCAs, as such research could potentially lead to the development of more effective immunotherapies. We underscore the need to pursue the identification of robust biomarkers.

CLIPPERS

We present the clinical case of a woman suffering from CLIPPERS syndrome (chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids). The images obtained from the brain magnetic resonance show the lesions typical of the disease.

[A case of chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) without relapse after early steroid treatment]

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a brainstem predominant lymphocytic inflammatory disease, which often relapses without oral immunosuppressants. This report describes a 37-year-old male case of CLIPPERS without relapse for 1 year after early steroid treatment. He was admitted to our hospital because of sensory disturbance in the left side of his body and ataxic gait. Gadolinium-enhanced T₁-weighted MRI revealed multiple punctate and curvilinear enhancements in the pons and right middle cerebellar peduncle. We started treatment with high-dose intravenous methylprednisolone (IVMP) therapy on the 20th day of the illness. His neurological symptoms dramatically improved. Follow-up MRI showed that the enhancing lesions disappeared. We diagnosed him with CLIPPERS based on the clinical course, radiological findings, and steroid response. He did not take any oral immunosuppressant after discharge. However, there was no clinical and radiological relapse for 1 year after the IVMP therapy. Although this case requires careful follow-up because of recurrence risk, early steroid treatment was possibly related to 1-year remission.

An Atypical Presentation of CLIPPERS, a Challenging Diagnosis of Reversible Early-Onset Dementia

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare inflammatory disorder featured by pontocerebellar dysfunctions and, in some cases, later cognitive disturbances. Here, we describe an atypical presentation of CLIPPERS, characterized by clinical onset with neuropsychiatric and cognitive symptoms. A 45-year-old man was referred to our Memory Clinic due to difficulties at work for over a month, caused by confusion and asthenia. Furthermore, insomnia and mood changes appeared. These disturbances were unresponsive to antipsychotic and antidepressant drugs. At admission, the patient presented also with severe cognitive impairment, urinary incontinence, ataxic gait, and limitation of lateral conjugate gaze. During the hospitalization, the patient underwent cerebrospinal fluid analysis, serum systemic autoimmune disorders laboratory research, neoplastic markers analysis, and brain MRI scan. The radiological and laboratory findings were compatible with the diagnosis of CLIPPERS. The sudden clinical and radiological improvement of the patient's conditions, after only a week of steroid therapy, further confirmed our clinical suspicion. The present case enhances the necessity to consider CLIPPERS in the differential diagnosis of pre-senile cognitive impairment, even in the absence of early pontocerebellar neurological signs. Before the spreading of the neuroinflammatory and degenerative processes, CLIPPERS represents one among the few possible reversible causes of cognitive decline.

Brainstem Encephalitis. The Role of Imaging in Diagnosis

Encephalitis is a relatively challenging rare condition caused by a diverse group of etiologies. Brainstem encephalitis/Rhombencephalitis (BE), which affects the cerebellum, pons, and medulla, is even less common and more challenging for diagnosis and treatment. At this time, there is scattered data about BE in the literature, mainly in the form of case reports and case series. In this manuscript, the imaging presentation of BE is reviewed with the help of case examples. Many imaging presentations are not pathognomonic for BE; however, in many cases, clinical presentation, the spatial distribution of lesions, and other associated radiological lesions can provide the radiologists and clinician the clues to an accurate diagnosis.

Asymptomatic brainstem lesions and pachymeningeal enhancement after anti-PD-1 therapy

Neurological immune-related adverse events (irAEs) are rare toxicities that occur following immune checkpoint inhibitor therapy. We propose that patients with thymic malignancies and graft-versus-host disease (GVHD) are predisposed to irAEs. We present two asymptomatic patients, one with thymoma and another with GVHD, who developed abnormal brain MRIs after treatment with programmed cell death protein 1 inhibitors. The first patient, with thymic cancer and thymoma, developed pontine enhancing MRI lesions following treatment with pembrolizumab. The second patient, with prior GVHD, developed pachymeningeal enhancement following treatment with nivolumab. IrAEs with abnormal MRI studies, despite asymptomatology, have significant impact on the treatment strategy for these patients.

Challenging Implications of Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids Syndrome with an Atypical Presentation: Report of Two Cases

BACKGROUND

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is an increasingly recognized neuroinflammatory syndrome that predominantly affects the pontine and cerebellar brain structures. Characteristically, patients will develop glucocorticoid-responsive brainstem disorders, demonstrate pontocerebellar contrast enhancement on magnetic resonance imaging (MRI), and exhibit an angiocentric, lymphocytic infiltrate in brain biopsies. We have presented and discussed 2 novel and challenging cases of CLIPPERS syndrome to highlight the clinical and radiological diversity of the syndrome.

CASE DESCRIPTION

The first case was of a 66-year-old male patient who had presented with dizziness, headaches, gait disturbances, mild cognitive impairment, and visual field loss to the left side. MRI revealed 1 cerebellar and 2 occipital contrast-enhancing lesions that were suspicious for intracerebral metastases. The second case was of a 53-year-old male patient who had presented with temporal lobe epilepsy, anomic aphasia, and mild cognitive impairment. MRI demonstrated 4 contrast-enhancing lesions in the pons, temporal lobe, and thalamus that were suspicious for intracerebral lymphoma. Because of the radiological presentation, neoplastic disease was the most plausible diagnosis for both patients. However, repeated biopsies ruled out tumor manifestation, and the findings were finally consistent with CLIPPERS syndrome. The significant and long-lasting response to immunosuppressive treatment confirmed the diagnosis.

CONCLUSIONS

In both cases, the characteristics of CLIPPERS syndrome imitated malignant tumor growth. This scenario can be challenging to clinicians and necessitates inclusion of this neuroinflammatory syndrome in the differential diagnosis of neuro-oncological disease.

[Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids]

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is an inflammatory disease of the central nervous system, mainly affecting the brain stem, cerebellum and spinal cord. The clinical picture includes gradually developing ataxia, double vision, dysarthria, pyramidal and cognitive impairment. Morphological examination reveals T-cell perivascular lymphocytic infiltration with CD4 lymphocytes predominance over CD8 lymphocytes. The cause of the disease is unknown. The article describes two patients (a 18-year-old woman and a 40-year-old man) with typical clinical and MRI manifestations of CLIPPERS, which was confirmed by brain biopsy in the female patient. The duration of follow-up was 3 and 7 years, respectively. Both patients survived an infection 2-3 weeks before the onset of disease that allows one to discuss its role in CLIPPERS pathogenesis. Both patients had a clear clinical and MRI responsiveness to steroids. In the female patient, steroids were replaced by intramuscular administration of the TNF-α blocker adalimumab. During 1,5 years of its use, there were no clinical relapses and pathological brain changes on MRI.

Brain miliary enhancement

PURPOSE

Miliary enhancement refers to the presence of multiple small, monomorphic, enhancing foci on T1-weighted post-contrast MRI images. In the absence of a clear clinical presentation, a broad differential diagnosis may result in invasive procedures and possibly brain biopsy for diagnostic purposes.

METHODS

An extensive review of the literature is provided for diseases that may present with miliary enhancement on T1-weighted brain MR images. Additional disease-specific findings, both clinical and radiological, are summarized and categorized by the presence or absence of perivascular space involvement.

RESULTS

Miliary pattern of enhancement may be due to a variety of underlying causes, including inflammatory, infectious, nutritional or neoplastic processes. The recognition of disease spread along the perivascular spaces in addition to the detection or exclusion of disease-specific features on MRI images, such as leptomeningeal enhancement, presence of haemorrhagic lesions, spinal cord involvement and specific localisation or systemic involvement, allows to narrow the potential differential diagnoses.

CONCLUSION

A systematic approach to disease-specific findings from both clinical and radiological perspectives might facilitate diagnostic work-up, and recognition of disease spread along the perivascular spaces may help narrowing down differential diagnoses and may help to minimize the use of invasive diagnostic procedures.

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.