Punctate and curvilinear gadolinium enhancing lesions in the brain: a practical approach

Perivascular enhancement pattern: Identification, diagnostic spectrum and practical approach - A pictorial review

Perivascular spaces (PVS) are fluid-filled structures that form the immediate peripheral environment of small cerebral vessels. They are a central component of the glymphatic system, which plays a crucial role in maintaining cerebral homeostasis. Their involvement in central nervous system diseases is currently a major focus of research, particularly in neuroimaging. Pathological enhancement of PVS on post-contrast MRI sequences creates a distinctive pattern due to their topography. As with other intracranial enhancement patterns, a differential diagnosis approach can be applied to perivascular enhancement (PVE). However, it is particularly challenging due to the rarity and complexity of the conditions involved. This article aims to facilitate the recognition of PVE pattern, to highlight the various causal conditions and to propose a practical diagnostic approach.

Erdheim-Chester Disease Masquerading as CLIPPERS

OBJECTIVES

To present 4 patients with Erdheim-Chester disease (ECD) based on clinical, radiologic, histopathologic, and molecular genetic findings who had enhancing brainstem lesions and were initially believed to have chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS).

METHODS

Case series.

RESULTS

Although patients with ECD can demonstrate clinical and imaging features similar to CLIPPERS, refractoriness to corticosteroids, lack of fulfillment of specific MRI criteria (i.e., enhancing lesions >3 mm, T2 abnormalities that exceed areas of T1 postgadolinium enhancement), and systemic findings such as "hairy kidney" appearance and metadiaphyseal osteosclerosis on 18F-fluorodeoxyglucose PET-CT help discriminate it from CLIPPERS.

DISCUSSION

ECD is a histiocytic neoplasm characterized by multiorgan infiltration of clonal histiocytes carrying activating variants of the MAPK-ERK pathway. Neurologic involvement occurs in up to 40% of ECD with frequent brainstem lesions that can mimic acquired neuroinflammatory disorders, such as CLIPPERS. ECD is an important CLIPPERS mimic with distinct pathophysiology and targeted treatments. We highlight the need to consider histiocytic disorders among other alternate diagnoses when findings are not classic for CLIPPERS.

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.

Cerebral enhancement in MOG antibody-associated disease

INTRODUCTION

Limited data exist on brain MRI enhancement in myelin-oligodendrocyte-glycoprotein (MOG) antibody-associated disease (MOGAD) and differences from aquaporin-4-IgG-positive-neuromyelitis-optica-spectrum-disorder (AQP4+NMOSD), and multiple sclerosis (MS).

METHODS

In this retrospective observational study, we identified 122 Mayo Clinic MOGAD patients (1 January 1996-1 July 2020) with cerebral attacks. We explored enhancement patterns using a discovery set (n=41). We assessed enhancement frequency and Expanded Disability Status Scale scores at nadir and follow-up in the remainder (n=81). Two raters assessed T1-weighted-postgadolinium MRIs (1.5T/3T) for enhancement patterns in MOGAD, AQP4+NMOSD (n=14) and MS (n=26). Inter-rater agreement was assessed. Leptomeningeal enhancement clinical correlates were analysed.

RESULTS

Enhancement occurred in 59/81 (73%) MOGAD cerebral attacks but did not influence outcome. Enhancement was often patchy/heterogeneous in MOGAD (33/59 (56%)), AQP4+NMOSD (9/14 (64%); p=0.57) and MS (16/26 (62%); p=0.63). Leptomeningeal enhancement favoured MOGAD (27/59 (46%)) over AQP4+NMOSD (1/14 (7%); p=0.01) and MS (1/26 (4%); p<0.001) with headache, fever and seizures frequent clinical correlates. Ring enhancement favoured MS (8/26 (31%); p=0.006) over MOGAD (4/59 (7%)). Linear ependymal enhancement was unique to AQP4+NMOSD (2/14 (14%)) and persistent enhancement (>3 months) was rare (0%-8%) across all groups. Inter-rater agreement for enhancement patterns was moderate.

CONCLUSIONS

Enhancement is common with MOGAD cerebral attacks and often has a non-specific patchy appearance and rarely persists beyond 3 months. Leptomeningeal enhancement favours MOGAD over AQP4+NMOSD and MS.

European Stroke Organisation (ESO) guidelines on Primary Angiitis of the Central Nervous System (PACNS)

The European Stroke Organisation (ESO) guideline on Primary Angiitis of the Central Nervous System (PACNS), developed according to ESO standard operating procedures (SOP) and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, was elaborated to assist clinicians in the diagnostic and treatment pathway of patients with PACNS in their decision making. A working group involving vascular neurologists, neuroradiologists, rheumatologists, a neuropathologist and a methodologist identified 17 relevant clinical questions; these were addressed according to the patient/population, intervention, comparison and outcomes (PICO) framework and systematic literature reviews were performed. Notably, each PICO was addressed with respect to large vessel (LV)-PACNS and small vessel (SV)-PACNS. Data to answer many questions were scarce or lacking and the quality of evidence was very low overall, so, for some PICOs, the recommendations reflect the ongoing uncertainty. When the absence of sufficient evidence precluded recommendations, Expert Consensus Statements were formulated. In some cases, this applied to interventions in the diagnosis and treatment of PACNS which are embedded widely in clinical practice, for example patterns of cerebrospinal fluid (CSF) and Magnetic Resonance Imaging (MRI) abnormalities. CSF analysis for hyperproteinorrachia and pleocytosis does not have evidence supporting their use as diagnostic tools. The working group recommended that caution is employed in the interpretation of non-invasive vascular imaging due to lack of validation and the different sensitivities in comparison with digital subtraction angiography (DSA) and histopathological analyses. Moreover, there is not a neuroimaging pattern specific for PACNS and neurovascular issues are largely underreported in PACNS patients. The group's recommendations on induction and maintenance of treatment and for primary or secondary prevention of vascular events also reflect uncertainty due to lack of evidence. Being uncertain the role and practical usefulness of current diagnostic criteria and being not comparable the main treatment strategies, it is suggested to have a multidisciplinary team approach in an expert center during both work up and management of patients with suspected PACNS. Highlighting the limitations of the currently accepted diagnostic criteria, we hope to facilitate the design of multicenter, prospective clinical studies and trials. A standardization of neuroimaging techniques and reporting to improve the level of evidence underpinning interventions employed in the diagnosis and management of PACNS. We anticipate that this guideline, the first comprehensive European guideline on PACNS management using GRADE methodology, will assist clinicians to choose the most effective management strategy for PACNS.

"Bunch of acai berries sign": a new radiological sign in patients with CNS involvement in Chagas disease

Chagas disease is an infection caused by Trypanosoma cruzi, a parasite endemic in Latin America. Acute involvement of the CNS by Chagas has been considered rare, but presumed reactivation of chronic disease in immunosuppressed patients has been the subject of recent reports. Our objective is to describe the clinical and imaging characteristics of four patients with Chagas disease and CNS involvement, and the patients had to have available MRI and a diagnosis confirmed by biopsy. The imaging findings were similar, highlighting the presence of focal cerebral lesions with hypointensity on T2-WI, and these lesions assume a "bunch of acai berries appearance", a fruit involved in the transmission of T. cruzi. The post Gd T1-WI shows punctate enhancement. Knowledge of this pattern may be crucial to recognize this disease in immunocompromised patients from endemic areas.

The Use of Intracranial Vessel Wall Imaging in Clinical Practice

Three-dimensional vessel wall MR imaging has gained popularity in the diagnosis and management of patients with cerebrovascular disease in clinical practice. Vessel wall MR imaging is an imaging technique that delivers a fundamentally different viewpoint by emphasizing on the pathology of the vessel wall as opposed to traditional descriptions that focus on the vessel lumen. It shows a crucial power in detecting vessel wall changes in patients with diseases including, but not limited to, central nervous system vasculitis, moyamoya disease, aneurysms, dissections, and intracranial atherosclerotic disease.

Immune-mediated diseases involving central and peripheral nervous systems

BACKGROUND AND PURPOSE

In addition to combined central and peripheral demyelination, other immune diseases could involve both the central nervous system (CNS) and peripheral nervous system (PNS).

METHODS

To identify immune-mediated diseases responsible for symptomatic combined central/peripheral nervous system involvement (ICCPs), we conducted a multicentric retrospective study and assessed clinical, electrophysiological, and radiological features of patients fulfilling our ICCP criteria.

RESULTS

Thirty patients (20 males) were included and followed during a median of 79.5 months (interquartile range [IQR] = 43-145). The median age at onset was 51.5 years (IQR = 39-58). Patients were assigned to one of four groups: (i) monophasic disease with concomitant CNS/PNS involvement including anti-GQ1b syndrome (acute polyradiculoneuropathy + rhombencephalitis, n = 2), checkpoint inhibitor-related toxicities (acute polyradiculoneuropathy + encephalitis, n = 3), and anti-glial fibrillary acidic protein astrocytopathy (subacute polyradiculoneuropathy and meningoencephalomyelitis with linear gadolinium enhancements, n = 2); (ii) chronic course with concomitant CNS/PNS involvement including paraneoplastic syndromes (ganglionopathy/peripheral hyperexcitability + limbic encephalitis, n = 4); (iii) chronic course with sequential CNS/PNS involvement including POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) syndrome (polyradiculoneuropathy + strokes, n = 2), histiocytosis (polyradiculoneuropathy + lepto-/pachymeningitis, n = 1), and systemic vasculitis (multineuropathy + CNS vasculitis/pachymeningitis, n = 2); and (iv) chronic course with concomitant or sequential CNS/PNS involvement including combined central and peripheral demyelination (polyradiculoneuropathy + CNS demyelinating lesions, n = 10) and connective tissue diseases (ganglionopathy/radiculopathy/multineuropathy + limbic encephalitis/transverse myelitis/stroke, n = 4).

CONCLUSIONS

We diagnosed nine ICCPs. The timing of central and peripheral manifestations and the disease course help determine the underlying immune disease. When antibody against neuroglial antigen is identified, CNS and PNS involvement is systematically concomitant, suggesting a common CNS/PNS antigen and a simultaneous disruption of blood-nerve and blood-brain barriers.

Adult-Onset Genetic Central Nervous System Disorders Masquerading as Acquired Neuroinflammatory Disorders: A Review

Importance

Adult-onset genetic disorders may present with clinical and magnetic resonance imaging (MRI) features suggestive of acquired inflammatory diseases. An ever-growing number of potentially treatable adult-onset genetic neuroinflammatory disorders have been described in the past few years that need to be rapidly identified.

Observations

Adult-onset acquired neuroinflammatory disorders encompass a large group of central nervous system (CNS) diseases with varying presentation, MRI characteristics, and course, among which the most common is multiple sclerosis. Despite recent progress, including the discovery of specific autoantibodies, a significant number of adult-onset neuroinflammatory disorders with progressive or relapsing course still remain without a definite diagnosis. In addition, some patients with genetic disorders such as leukodystrophies, hemophagocytic lymphohistiocytosis, or genetic vasculopathies can mimic acquired neuroinflammatory disorders. These genetic disorders, initially described in pediatric populations, are increasingly detected in adulthood thanks to recent progress in molecular genetics and the larger availability of high-throughput sequencing technologies.

Conclusions and Relevance

Genetic adult-onset neuroinflammatory diseases are at the border between primary CNS inflammatory diseases and systemic disorders with multiorgan involvement and predominantly neurologic manifestations. Neurologists must be aware of the main clues and red flags so they can confirm a diagnosis early, when some of these genetic disorders can be successfully treated.

Multiple Cerebral Infarction Associated with Cerebral Vasculitis in a Patient with Ulcerative Colitis

A 40-year-old man was admitted to the hospital due to both a worsening of symptoms associated with ulcerative colitis (UC), which had been diagnosed 3 years previously, and limb paralysis. Colonoscopy revealed severe pancolitis-type UC. He was diagnosed with cerebral vasculitis with multiple white matter infarctions associated with the disease activity of UC by contrast-enhanced head magnetic resonance imaging. Mesalazine at 4,000 mg/day and prednisolone at 60 mg/day were started, and the prednisolone dosage was thereafter gradually reduced and switched to golimumab. He achieved a long-term remission from UC, and thereafter his neurological abnormalities improved significantly. He had no recurrence of cerebral infarction.

Clinical and Radiological Features of Adult Onset Bilateral Medial Frontal Cerebral Cortical Encephalitis With Anti-myelin Oligodendrocyte Glycoprotein Antibody

Objective: To clarify the clinical and radiological features of adult onset anti-myelin oligodendrocyte glycoprotein (MOG) antibody-associated bilateral medial frontal cerebral cortical encephalitis (BFCCE). Methods: We systematically reviewed the literature for patients with anti-MOG antibody-associated BFCCE. Patients who were also positive for other encephalitis-related autoantibodies were excluded from the study. The frequency of several characteristic neurological symptoms and lesion distributions were analyzed. Results: We identified six patients with anti-MOG antibody-associated BFCCE. Among them, 6/6 had headache, 4/6 had fever, 3/6 had seizure, 2/6 had paraparesis, 2/6 had lethargy, and 2/6 had memory disturbance. CSF pleocytosis was observed in 5/6 patients, while CSF myelin basic protein was not elevated in any of the six patients. On brain MRI, 6/6 had bilateral medial frontal cortical lesions, 3/6 had corpus callosum lesions, and 3/6 had leptomeningeal enhancements. Most of the lesions were distributed in the territory of the anterior cerebral artery (ACA). Conclusion: Our results indicate that anti-MOG antibody-associated BFCCE presents with characteristic clinical symptoms and MRI findings, which might reflect lesion formation in the ACA territory.

Retrospective Observational Study of Brain MRI Findings in Patients with Acute SARS-CoV-2 Infection and Neurologic Manifestations

Background This study provides a detailed imaging assessment in a large series of patients infected with coronavirus disease 2019 (COVID-19) and presenting with neurologic manifestations. Purpose To review the MRI findings associated with acute neurologic manifestations in patients with COVID-19. Materials and Methods This was a cross-sectional study conducted between March 23 and May 7, 2020, at the Pitié-Salpêtrière Hospital, a reference center for COVID-19 in the Paris area. Adult patients were included if they had a diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with acute neurologic manifestations and referral for brain MRI. Patients with a prior history of neurologic disease were excluded. The characteristics and frequency of different MRI features were investigated. The findings were analyzed separately in patients in intensive care units (ICUs) and other departments (non-ICU). Results During the inclusion period, 1176 patients suspected of having COVID-19 were hospitalized. Of 308 patients with acute neurologic symptoms, 73 met the inclusion criteria and were included (23.7%): thirty-five patients were in the ICU (47.9%) and 38 were not (52.1%). The mean age was 58.5 years ± 15.6 [standard deviation], with a male predominance (65.8% vs 34.2%). Forty-three patients had abnormal MRI findings 2-4 weeks after symptom onset (58.9%), including 17 with acute ischemic infarct (23.3%), one with a deep venous thrombosis (1.4%), eight with multiple microhemorrhages (11.3%), 22 with perfusion abnormalities (47.7%), and three with restricted diffusion foci within the corpus callosum consistent with cytotoxic lesions of the corpus callosum (4.1%). Multifocal white matter-enhancing lesions were seen in four patients in the ICU (5%). Basal ganglia abnormalities were seen in four other patients (5%). Cerebrospinal fluid analyses were negative for SARS-CoV-2 in all patients tested (n = 39). Conclusion In addition to cerebrovascular lesions, perfusion abnormalities, cytotoxic lesions of the corpus callosum, and intensive care unit-related complications, we identified two patterns including white matter-enhancing lesions and basal ganglia abnormalities that could be related to severe acute respiratory syndrome coronavirus 2 infection. © RSNA, 2020 Online supplemental material is available for this article.

Atypical Deep Cerebral Vein Thrombosis with Hemorrhagic Venous Infarction in a Patient Positive for COVID-19

There is growing evidence that Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) has a neurotropic and neuroinvasive potential. In particular, neurologic complications associated with the infection by SARS-CoV-2 include strokes that may result from a dysregulated inflammatory response to the infection. We report an atypical deep cerebral vein thrombosis complicated with hemorrhagic venous infarction in a patient positive for SARS-CoV-2 with no risk factors for thrombosis.

CD8+ T-cell encephalitis mimicking PRES in AIDS: a case report

Background

Diverse mechanisms including infections, autoimmune inflammatory reactions, neoplasms, and degeneration are involved in the central nervous system in cases of acquired immune deficiency syndrome. In such cases, it is difficult to determine the precise pathogenesis by radiological examination and laboratory testing.

Case presentation

We report a 37-year-old Japanese woman who had untreated hypertension and gender identity disorder and had been taking testosterone injections since she was 19 years old. She developed a headache and visual field deficits together with elevated blood pressure. According to radiological findings, she was initially suspected as having posterior reversible encephalopathy syndrome in the right parieto-occipital lobe with reversible cerebral vasoconstriction syndrome. Human immunodeficiency virus antibody was positive and the CD4⁺ T-lymphocyte count was 140 cells/μl. Therefore, antiretroviral therapy was started. Antiretroviral therapy suppressed the activity of acquired immune deficiency syndrome but worsened her visual symptoms and expanding radiological lesions. Brain biopsy led to the diagnosis of CD8⁺ encephalitis, and she also fulfilled the diagnosis of paradoxical immune reconstitution inflammatory syndrome. Corticosteroid therapy alleviated her symptoms.

Conclusions

This is a rare case of CD8⁺ encephalitis, with an exacerbation owing to paradoxical immune reconstitution inflammatory syndrome after antiretroviral therapy, which radiologically mimicked posterior reversible encephalopathy syndrome. Corticosteroid therapy was effective; thus, it is important to provide a pathological diagnosis in such cases.

Diagnostic and therapeutic issues of inflammatory diseases of the elderly

Inflammatory diseases of the central nervous system (CNS) mainly occur during early adulthood and multiple sclerosis (MS) represents the overwhelming majority of these disorders. Nevertheless, MS only rarely begins after 50 years and a diagnosis of late-onset MS should only be done when clinical as well as radiological and biological findings are typical of MS since the probability of misdiagnosis is higher in elderly patients. Indeed, in patients aged over 50 years, along with a relative decrease of MS incidence, other inflammatory diseases of the CNS but also differential diagnoses including neoplastic as well as infectious disorders should be thoroughly searched to avoid diagnostic mistakes and the prescription of inadequate and potentially harmful immunomodulatory/immunosuppressive therapies. Moreover, aging is associated with diverse immune changes also known as immunosenescence resulting in, notably, higher risk of comorbidities (including vascular diseases) and infections which need to be considered when planning medical treatments of elderly patients with inflammatory diseases of the CNS. Herein, therapeutic and diagnostic challenges faced by neurologists are reviewed to ease patient management.

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.

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.

The "milky way" galaxy of HIV-related central nervous system immune reaction syndromes

The landscape of central nervous system HIV infection is rapidly changing, leading to the recognition of a new constellation of overlapping syndromes and to a better insight for the elder ones. Among these, progressive multifocal leukoencephalopathy (PML) still poses several diagnostic and therapeutic challenges; nevertheless, recent developments in understanding PML in patients with multiple sclerosis may have benefitted HIV-positive patients suffering from PML too. We describe a peculiar case of PML-immune reconstitution inflammatory syndrome (IRIS) presenting a punctate pattern with "milky way" appearance on magnetic resonance imaging. Despite the fact that brain imaging and histopathology remain the mainstays for extricating through the expanding galaxy of HIV-related central nervous system dysimmune syndromes and although punctate pattern has been already well acknowledged as a suggestive finding of PML among patients on natalizumab, this radiological presentation is still poorly recognised in AIDS-related PML cases, leading to possible life-threatening diagnostic delays. This is also the first report about intravenous immunoglobulin treatment in AIDS-related PML-IRIS; the favourable clinical and radiological outcome of our case and the preliminary administrations of intravenous immunoglobulins in natalizumab-associated PML-IRIS from literature support probable benefits also among HIV-positive patients.

Unusual CLIPPERS presentation and role of MRI examination in the proper diagnostic assessment: A case report

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CLIPPERS is a recently described, underestimated CNS inflammatory disorder involving midbrain and cerebellum.

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Unusual clinical presentation can make the diagnosis particularly challenging to the clinician.

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MRI plays a pivotal role in the correct diagnostic assessment, helping discriminate CLIPPERS from potential mimickers.

Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids syndrome (CLIPPERS) is a newly described, underestimated CNS inflammatory disorder involving predominantly the midbrain and the cerebellum. CLIPPERS pathogenesis is largely unknown, and its clinical manifestations are polymorphic and sometimes confounding. Recently clinical, radiological and pathological diagnostic criteria have been proposed to discriminate CLIPPERS from potential mimickers, but the diagnosis still remains challenging. Here we present the case of a patient with radiological findings consistent with CLIPPERS but with atypical clinical presentation, highlighting the importance of a proper diagnostic assessment.

[Misleading cerebral arterial wall gadolinium-enhancement in malignant lymphoma]

A previously healthy, 77-year-old woman presented with gradual cognitive decline and acute gait imbalance. On admission, despite no obvious paralysis, she tilted to the right. Her Mini-Mental State Examination score was slightly low (23/30). Gadolinium-enhanced, high-resolution T₁-weighted MRI showed abnormal arterial wall enhancement at the bilateral middle cerebral and right internal carotid arteries. The combination of arterial and parenchymal enhancement limited to the central nervous system (CNS), normal laboratory data including soluble interleukin-2 receptor, and random skin and bone-marrow biopsies was suggested of primary angiitis of the CNS (PACNS). However, a biopsy specimen from the right insula showed CD20-positive lymphoma cells indicative of diffuse large B-cell lymphoma. After receiving chemotherapy, above-mentioned abnormal findings were significantly improved. Considering the increasing clinical application of high resolution MRI, there is a risk that patients may receive a presumptive diagnosis of PACNS and immunosuppressive treatment without biopsy confirmation. It should be noted that a combination of abnormal arterial wall and linear parenchymal enhancement similar to that found for PACNS on high-resolution MRI may occur in patients with primary central nervous system lymphoma.

Neuroradiological features of lymphomatosis cerebri: A systematic review of the English literature with a new case report

Lymphomatosis cerebri is a rare form of diffusely infiltrating primary central nervous system (CNS) lymphoma (PCNSL). The neuroradiological findings of lymphomatosis cerebri have not been adequately characterized, as the relevant literature consists only of case reports and small case series. The present study describes an unusual presentation of lymphomatosis cerebri in a 56-year-old immunocompetent woman who presented with diffusely infiltrating lesions with perivascular curvilinear enhancement on initial magnetic resonance imaging (MRI) and multiple nodules on the later follow-up computed tomography (CT) scan. A systematic review of the literature is also performed searching PubMed between January 1996 and December 2016 to collect all pertinent case reports and series written in the English language with pathologically confirmed lymphomatosis cerebri and diffuse infiltrative PCNSL without cohesive masses on initial MRI. A total of 45 cases were identified from 39 articles and the present case report. The patient ages ranged from 28 to 85 years (mean, 57.3 years). Only 3 patients (6.7%) were immunosuppressed (acquired immune deficiency syndrome patients). The most common clinical presentation was cognitive changes or dementia (46.7%). Cerebrospinal fluid analysis in all cases was non-specific. Diffuse and asymmetric abnormal T2-hyperintensity in deep and subcortical white matter was observed in all cases. Gray matter involvement (17.8%), spreading along the corticospinal tract (35.6%) and a slight mass effect (51.1%) also were observed. Contrast-enhanced patterns on MRI could be divided into three forms of non-enhancement (64.4%) and non-mass-like enhancement (35.6%) on initial MRI, as well as nodular or mass-like enhancement on the later follow-up MRI (15.6%). There were non-specific findings on magnetic resonance spectroscopy for 4 patients, on positron emission tomography/CT for 12 patients and on single-photon emission CT for 1 patient. Diagnosis was established by brain biopsy in 35 cases (77.8%) and autopsy in 9 cases (20%), involving B-cell lymphoma in 40 cases (88.9%) and T-cell lymphoma in 4 cases (8.9%). In conclusion, lymphomatosis cerebri, namely diffuse PCNSL or diffuse lymphoma of the CNS, is characterized by rapidly progressive dementia in the elderly, diffusely infiltrated CNS white matter along the corticospinal tract, possible involvement of the gray matter, a slight mass effect and varied contrast-enhancement patterns on MRI. Non-enhancement or non-mass-like enhancement on MRI may be a special form of diffuse PCNL during disease development and progression.

CLIPPERS

PURPOSE OF REVIEW

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a recently described treatable, inflammatory, brainstem predominant encephalomyelitis. The diagnosis of CLIPPERS is challenging without a specific biomarker, and thus it is important to consider if both the clinical and radiographic features are consistent with the diagnosis, or rather a disease mimicker.

RECENT FINDINGS

Many patients with CLIPPERS-like lesions have been described in the literature with follow-up revealing a range of alternative diagnoses, such as malignancies, vasculitis, and other specific inflammatory diseases. As a result, some have proposed that CLIPPERS might represent a pre-malignancy state or simply an initial clinical syndrome of a variety of possible etiologies. We describe the typical clinical, radiographic, and pathological features of CLIPPERS and emphasize consideration for alternative diagnoses when findings are not classic. A recommended diagnostic evaluation and initial treatment plan is provided.

Therapeutic Approaches in CLIPPERS

OPINION STATEMENT

CLIPPERS for chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids, is a steroid-sensitive and steroid-dependent brainstem inflammatory disease of unknown origin. Since its first description in 2010, about 60 cases have been reported throughout the world. The mean age at onset is 50 years and men seem to be more frequently affected. In patients without chronic corticosteroid therapy or immunosuppressive agents, the disease had a relapsing remitting course, and the mean annualized relapse rate was 0.5. During attacks, although clinical and radiological improvement after high doses of corticosteroids was systematically observed, patients could display subsequent disability and hindbrain atrophy. Since no progressive course was observed, clinical and radiological sequelae were correlated with previous severe attacks. Therefore, maintaining the disease in remission may prevent the accumulation of disability. In the literature, no relapse occurred when chronic corticosteroid therapy was maintained above 20 mg per day. However, steroids side effects led to propose corticosteroid-sparing therapies. Unfortunately, no controlled therapy studies for CLIPPERS have been performed yet, and no therapeutic recommendations exist. Using the PubMed database, all articles having the following keywords "chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids" and "CLIPPERS" have been analysed. Considering that the mean annual relapse rate was 0.5, and that no relapse occurred when corticosteroid therapy was maintained above 20 mg per day, the therapeutic efficiency of corticosteroid-sparing agents was considered as "probable" when patients had a relapse-free period ≥24 months, in the absence of concomitant corticosteroid therapy. Corticosteroid-sparing agents whose efficiency is "probable" are methotrexate in two cases, cyclophosphamide in one case and hydroxychloroquine in one case. Considering the risk benefit ratio of corticosteroid-sparing agents, methotrexate seems to be the most suitable. Nevertheless, randomized controlled trials testing the different corticosteroid-sparing agents in CLIPPERS are necessary.

Chronic Graft-versus-host Disease Presenting with Multiple Punctate Intracranial Lesions on Contrast-enhanced Magnetic Resonance Imaging

Central nervous system graft-versus-host disease can present quite a diagnostic challenge. We herein present a case of histologically-confirmed chronic graft versus host disease (GVHD) involving the central nervous system that occurred at 19 months after peripheral blood stem cell transplantation. Cranial magnetic resonance imaging showed areas of confluent hyperintensity in the deep/subcortical white matter with multiple punctate and curvilinear gadolinium enhancements, suggesting the disruption of the blood-brain barrier. A brain biopsy revealed perivascular CD3-positive T cell infiltration around the small vessels. We propose that the detection of punctate-enhanced lesions by magnetic resonance imaging may be a useful finding that facilitates the early diagnosis of chronic GVHD involving the central nervous system.

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.