Tumefactive Demyelination Lesions: Report on three cases.

PURPOSE: Tumefactive demyelination (TD) lesion and its subtype Balo's concentric sclerosis (BCS), are rare manifestations of central nervous system demyelinating disease. Because of its rarity, physicians might hesitate in reaching a diagnosis or initiating steroid pulse therapy. This study aims at pinpointing the key neuroimaging features to distinguish TD lesions from surgical conditions, and illustrating the clinical outcomes of patients with TD lesions. CASE REPORT: Two of the three patients had solitary TD lesions, one 47-year-old man presenting with newly onset seizure and another 54-year-old women suffering from progressive hemiparesis. The male patient underwent craniotomy for mass excision without further steroid therapy, while the female patient received methylprednisolone pulse therapy only. Both patients remained free of clinical and radiological relapses over the past 6-7 years, leading to the diagnosis of clinically isolated syndrome. The third case is a 30-year-old woman with subacute onset of dysarthria and hemiparesis. She had two BCS lesions along with other demyelinating lesions in the juxtacortical and periventricular regions, cerebellar peduncles, and spinal cord, fulfilling dissemination in time and space. Her neurological deficits resolved after pulse therapy, and she received long-term disease modifying therapy for multiple sclerosis. CONCLUSION: This study underscores the diverse neuroimaging and clinical presentations of patients with TD lesions, and emphasizes the importance of clinical vigilance regarding this rare condition.

Pediatric tumefactive multiple sclerosis case (with baló-like lesions), diagnostic and treatment challenges.

BACKGROUND: Multiple sclerosis (MS) is a demyelinating disease of the central nervous system, rare during childhood. MS variations, like tumefactive MS and Balo concentric sclerosis, constitute puzzling to treat diagnostic dilemmas for pediatric patients. Differential diagnosis, mainly from brain tumors, is an absolute necessity. In addition, apart from treating acute attacks, immunomodulatory alternatives are limited. CASE: We present a 12.5-year-old boy diagnosed, 5 years ago, with tumefactive relapsing-remitting MS, with severe recurrent clinical attacks. Definite diagnosis of demyelination was achieved via combined brain imaging including magnetic resonance (MR) imaging, MR spectroscopy and computed tomography, avoiding brain biopsy. Acute attacks showed satisfactory response to aggressive treatment choices, like plasmapheresis and cyclophosphamide, but age-appropriate immunomodulating treatment was available, only 2 years later. Finally, after a last radiological relapse, when he was 10 years old, fingolimod was initiated. He has been clinically and radiologically stable since, presenting an excellent treatment tolerance.

[TUMOR-LIKE EFFECT AS INITIAL PRESENTATION OF PEDIATRIC MULTIPLE SCLEROSIS].

INTRODUCTION: In both children and adults, magnetic resonance imaging of the brain in cases of multiple sclerosis (MS) has typical indications, where one of the key points for differentiating between demyelinating processes and place-taking processes is the fact that most of the lesions that appear in multiple sclerosis do not cause a mass effect or much edema around them. There are several uncommon subtypes of multiple sclerosis that can appear specifically in adolescents, presenting with a stormy clinical course and accompanied by brain lesions that resemble space-occupying lesions. These include Marburg disease, Balò's concentric sclerosis, and tumefactive MS. These unusual presentations raise the question regarding the ability to distinguish between neoplastic and demyelinating processes. In this article we present two case studies that illustrate this diagnostic dilemma and an accompanying literature review.

Delineating selective vulnerability of inhibitory interneurons in Alpers' syndrome.

AIMS: Alpers' syndrome is a severe neurodegenerative disease typically caused by bi-allelic variants in the mitochondrial DNA (mtDNA) polymerase gene, POLG, leading to mtDNA depletion. Intractable epilepsy, often with an occipital focus, and extensive neurodegeneration are prominent features of Alpers' syndrome. Mitochondrial oxidative phosphorylation (OXPHOS) is severely impaired with mtDNA depletion and is likely to be a major contributor to the epilepsy and neurodegeneration in Alpers' syndrome. We hypothesised that parvalbumin-positive(+) interneurons, a neuronal class critical for inhibitory regulation of physiological cortical rhythms, would be particularly vulnerable in Alpers' syndrome due to the excessive energy demands necessary to sustain their fast-spiking activity. METHODS: We performed a quantitative neuropathological investigation of inhibitory interneuron subtypes (parvalbumin+, calretinin+, calbindin+, somatostatin interneurons+) in postmortem neocortex from 14 Alpers' syndrome patients, five sudden unexpected death in epilepsy (SUDEP) patients (to control for effects of epilepsy) and nine controls. RESULTS: We identified a severe loss of parvalbumin+ interneurons and clear evidence of OXPHOS impairment in those that remained. Comparison of regional abundance of interneuron subtypes in control tissues demonstrated enrichment of parvalbumin+ interneurons in the occipital cortex, while other subtypes did not exhibit such topographic specificity. CONCLUSIONS: These findings suggest that the vulnerability of parvalbumin+ interneurons to OXPHOS deficits coupled with the high abundance of parvalbumin+ interneurons in the occipital cortex is a key factor in the aetiology of the occipital-predominant epilepsy that characterises Alpers' syndrome. These findings provide novel insights into Alpers' syndrome neuropathology, with important implications for the development of preclinical models and disease-modifying therapeutics.

Antibody signatures in patients with histopathologically defined multiple sclerosis patterns.

Early active multiple sclerosis (MS) lesions can be classified histologically into three main immunopathological patterns of demyelination (patterns I-III), which suggest pathogenic heterogeneity and may predict therapy response. Patterns I and II show signs of immune-mediated demyelination, but only pattern II is associated with antibody/complement deposition. In pattern III lesions, which include Baló's concentric sclerosis, primary oligodendrocyte damage was proposed. Serum antibody reactivities could reflect disease pathogenesis and thus distinguish histopathologically defined MS patterns. We established a customized microarray with more than 700 peptides that represent human and viral antigens potentially relevant for inflammatory demyelinating CNS diseases, and tested sera from 66 patients (pattern I n = 12; II n = 29; III n = 25, including 8 with Baló's), healthy controls, patients with Sjögren's syndrome and stroke patients. Cell-based assays were performed for aquaporin 1 (AQP1) and AQP4 antibody detection. No single peptide showed differential binding among study cohorts. Because antibodies can react with different peptides from one protein, we also analyzed groups of peptides. Patients with pattern II showed significantly higher reactivities to Nogo-A peptides as compared to patterns I (p = 0.02) and III (p = 0.02). Pattern III patients showed higher reactivities to AQP1 (compared to pattern I p = 0.002, pattern II p = 0.001) and varicella zoster virus (VZV, compared to pattern II p = 0.05). In patients with Baló's, AQP1 reactivity was also significantly higher compared to patients without Baló's (p = 0.04), and the former revealed distinct antibody signatures. Histologically, Baló's patients showed loss of AQP1 and AQP4 in demyelinating lesions, but no antibodies binding conformational AQP1 or AQP4 were detected. In summary, higher reactivities to Nogo-A peptides in pattern II patients could be relevant for enhanced axonal repair and remyelination. Higher reactivities to AQP1 peptides in pattern III patients and its subgroup of Baló's patients possibly reflect astrocytic damage. Finally, latent VZV infection may cause peripheral immune activation.

Heterogeneity of Baló's concentric sclerosis: a study of eight cases with different therapeutic concepts.

BACKGROUND: Baló's Concentric Sclerosis (BCS) is a rare heterogeneous demyelinating disease with a variety of phenotypes on Magnetic Resonance Imaging (MRI). Existing literature lacks data especially on the therapeutic approach of the disease which we intended to elucidate by means of suggesting a new possible BCS classification and introducing different therapeutic concepts based on each BCS-subgroup characteristics. METHODS: We present a retrospective study of eight treated patients with BCS-type lesions, emphasizing on MRI characteristics and differences on therapeutic maneuvers. RESULTS: Data analysis showed: at disease onset the BCS-type lesion was tumefactive (size ≥2 cm) in 6 patients, with a mean size of 2.7 cm (± 0.80 SD); a coexistence of MS-like plaques on brain MRI was identified in 7 patients of our cohort. The mean age was 26.3 years (±7.3 SD) at disease onset and the mean follow-up period was 56.8 months (range 9-132 months). According to radiological characteristics and response to therapies, we further categorized them into 3 subgroups: a) Group-1; BCS with or without coexisting nonspecific white matter lesions; poor response to intravenous methylprednisolone (IVMP); treated with high doses of immunosuppressive agents (4 patients), b) Group-2; BCS with typical MS lesions; good response to IVMP; treated with MS-disease modifying therapies (2 patients), c) Group-3; BCS with typical MS lesions; poor response to IVMP; treated with rituximab (2 patients). CONCLUSIONS: Our study introduces a new insight regarding the categorization of BCS into three subgroups depending on radiological features at onset and during the course of the disease, in combination with the response to different immunotherapies. Immunosuppressive agents such as cyclophosphamide are usually effective in BCS. However, therapeutic alternatives like anti-CD20 monoclonal antibodies or more classical disease-modifying MS therapies can be considered when BCS has also mixed lesions similar to MS. Future studies with a larger sample size are necessary to further establish these findings, thus leading to better treatment algorithms and improved clinical outcomes.

Myelinoclastic diffuse sclerosis (Schilder's disease) is immunologically distinct from multiple sclerosis: results from retrospective analysis of 92 lumbar punctures.

BACKGROUND: Myelinoclastic diffuse sclerosis (MDS; also termed Schilder's disease) is a rare inflammatory demyelinating disorder of the central nervous system characterised by demyelination of vast areas of the white matter. It is unclear whether MDS is a variant of multiple sclerosis (MS) or a disease entity in its own right. OBJECTIVE: To compare the cerebrospinal fluid (CSF) features of MDS with those of MS. METHODS: Retrospective analysis of the CSF profile of all patients with MDS reported in the medical literature between 1960 and 2018. RESULTS: The most striking finding was a substantial lack of oligoclonal bands (OCBs) in MDS, which were absent in at least 77% (30/39) of all lumbar punctures (LP) in the total cohort and in 86% in the subgroup of patients with normal very long-chain fatty acid serum ratios (VLCFA). Almost all cases published in the past 15 years were negative for OCBs. These findings are in contrast to MS, in which OCBs are present in up to 98% of cases (p < 0.00001 when compared with reference works in MS; both in adult and in pediatric patients). CSF pleocytosis was absent in at least 79% (46/58) of all LP (p < 0.0001 vs. MS) and in 92% (24/26) of LPs in the VLCFA-tested subgroup. CSF total protein levels were elevated in 56% of all LPs (p < 0.0001 vs. MS) and in 63% of LPs in the VLCFA-tested subgroup and were often higher than in typical MS (> 100 mg/dL in 13/22; up to 220 mg/dL). EBV serum antibodies, which are present in virtually all patients with MS, and the so-called MRZ (measles/rubella/zoster) reaction, a highly specific marker of MS, were absent in all of the few patients tested. In addition, we discuss further differences between MS and MDS, taking into account also Schilder's original comprehensive case description from 1912. CONCLUSION: In the majority of patients diagnosed with MDS, CSF features differ significantly from those typically found in MS and are more similar to those previously reported in patients with myelin oligodendrocyte glycoprotein-immunoglobulin G (IgG)-positive encephalomyelitis, aquaporin-4-IgG-positive neuromyelitis optica spectrum disorders or Baló's concentric sclerosis. Our data suggest that MDS and MS are immunopathologically distinct entities in the majority of cases.

Biophysical characterization Of Alpers encephalopathy associated mutants of human mitochondrial phenylalanyl-tRNA synthetase.

Mutations in nucleus-encoded mitochondrial aminoacyl-tRNA synthetases (mitaaRSs) lead to defects in mitochondrial translation affecting the expression and function of 13 subunits of the respiratory chain complex leading to diverse pathological conditions. Mutations in the FARS2 gene encoding human mitochondrial phenylalanyl-tRNA synthetase (HsmitPheRS) have been found to be associated with two different clinical representations, infantile Alpers encephalopathy and spastic paraplegia. Here we have studied three pathogenic mutants (Tyr144Cys, Ile329Thr, and Asp391Val) associated with Alpers encephalopathy to understand how these variants affect the biophysical properties of the enzyme. These mutants have already been reported to have reduced aminoacylation activity. Our study established that the mutants are significantly more thermolabile compared to the wild-type enzyme with reduced solubility in vitro. The presence of aggregation-prone insoluble HsmitPheRS variants could have a detrimental impact on organellar translation, and potentially impact normal mitochondrial function. © 2019 IUBMB Life, 71(8): 1141-1149, 2019 © 2019 IUBMB Life, 71(8):1141-1149, 2019.

[First description of Schilder's disease : Paul Ferdinand Schilder and his struggle for the delimitation of a new entity]. / Die Erstbeschreibung der Schilder-Krankheit : Paul Ferdinand Schilder und sein Ringen um die Abgrenzung einer neuen Entität.

Paul Ferdinand Schilder was born in Vienna in 1886 and died in New York in 1940. He is nowadays remembered predominantly for his contributions to modern psychiatry and psychotherapy; however, he was also a neurologist and neuroscientist and in particular in his early years, he researched and published on neuropathological topics. This paper focuses on his scientific work during his years in Middle Germany (1909-1914), where he worked with Gabriel Anton in Halle and Paul Flechsig in Leipzig. During those years, he laid the foundations for his definition, clinical classification and differentiation of encephalitis periaxialis diffusa. Today, this inflammatory brain disease is known as Schilder's disease and is of some importance as a rare differential diagnosis of multiple sclerosis (MS), especially in children. Schilder's reflections and findings were based on his scrupulous and detailed analysis of only a few medical histories, which also comprised histological neuropathological examinations, as well as on his extensive and critical review of the relevant literature of the time. His aim was to differentiate encephalitis periaxialis diffusa from brain tumors, MS and Heubner's diffuse sclerosis. Schilder's scientific achievement, made in relatively young years, is still impressive even to the present day due do its thoroughness and accuracy as well as the enormous workload and ambition it required. Even though ambitious, Schilder was always prepared to critically review his own ideas.

Baló's concentric sclerosis is immunologically distinct from multiple sclerosis: results from retrospective analysis of almost 150 lumbar punctures.

BACKGROUND: Baló's concentric sclerosis (BCS) is a rare inflammatory demyelinating disorder of the central nervous system characterised by concentric layers of demyelination. It is unclear whether BCS is a variant of multiple sclerosis (MS) or a disease entity in its own right. OBJECTIVE: To compare the cerebrospinal fluid (CSF) features of BCS to those of MS. METHODS: Retrospective analysis of the CSF profile of all patients with BCS reported in the medical literature between 1980 and 2017. RESULTS: In total, the results of 146 lumbar punctures (LP) in 132 patients were analysed. The most striking finding was a lack of CSF-restricted oligoclonal bands (OCB) in 66% (56/85) of all LP in the total BCS group, in 74% (14/19) in the subgroup of patients with both MRI and histological evidence for BCS, and in 82% (18/22) in the subgroup of patients with highest radiological confidence (high MRI quality, ≥ 3 layers of demyelination). OCB disappeared in 1/2 initially OCB-positive patients. These findings are in stark contrast to MS, in which OCB are present in ≥ 95% of patients and are thought to remain stably detectable over the entire course of disease (p < 0.000001). OCB frequency was low both in 'historic' patients (1980-2009; 37%) and in more recent patients (2010-2017; 31%). OCB-positive and OCB-negative patients did not differ significantly with regard to age, sex, disease duration, number of Baló-like lesions on MRI, number of relapses, treatment or final outcome. In accordance with the high rate of OCB negativity, Link's IgG index was negative in 63% of all tested samples (p < 0.000001 vs. MS). CSF pleocytosis was present in 28% (27/96; p < 0.000001 vs. MS) and elevated CSF total protein levels in 41% (31/76) of samples. CONCLUSION: OCB and IgG index frequencies in BCS are much more similar to those reported in neuromyelitis optica or myelin oligodendrocyte glycoprotein antibody-associated encephalomyelitis than to those in MS. Our findings suggest that in most cases BCS-like lesions denote the presence of a disease entity immunologically distinct from MS. In addition, we provide data on the demographics, clinical course and radiological features of BCS based on the largest cohort analysed to date.

Atypical inflammatory demyelinating lesions and atypical multiple sclerosis.

Atypical idiopathic inflammatory demyelinating disorders (IIDDs) of the brain have long been known to be disorders closely related to multiple sclerosis (MS), despite having distinctive clinical and radiological characteristics. Originally, they mostly corresponded to acute-onset variants of MS that classically had poor prognoses, such as Baló's concentric sclerosis, Marburg variant of MS and Schilder's disease, and their relationship with MS was based on their shared pathological findings and the co-occurrence of these variants in patients with typical MS. More recently, other atypical disorders, such as solitary sclerosis, have also been described as belonging to the MS spectrum, raising the question of their links with MS. Meanwhile, multiple MS mimics have been described and need to be considered in the differential diagnosis of MS. In addition, thorough characterization of these atypical entities, including advanced MRI and biological studies, is now warranted to further improve their management.

The presence of anaemia negatively influences survival in patients with POLG disease.

BACKGROUND: Mitochondria play an important role in iron metabolism and haematopoietic cell homeostasis. Recent studies in mice showed that a mutation in the catalytic subunit of polymerase gamma (POLG) was associated with haematopoietic dysfunction including anaemia. The aim of this study was to analyse the frequency of anaemia in a large cohort of patients with POLG related disease. METHODS: We conducted a multi-national, retrospective study of 61 patients with confirmed, pathogenic biallelic POLG mutations from six centres, four in Norway and two in the United Kingdom. Clinical, laboratory and genetic data were collected using a structured questionnaire. Anaemia was defined as an abnormally low haemoglobin value adjusted for age and sex. Univariate survival analysis was performed using log-rank test to compare differences in survival time between categories. RESULTS: Anaemia occurred in 67% (41/61) of patients and in 23% (14/61) it was already present at clinical presentation. The frequency of anaemia in patients with early onset disease including Alpers syndrome and myocerebrohepatopathy spectrum (MCHS) was high (72%) and 35% (8/23) of these had anaemia at presentation. Survival analysis showed that the presence of anaemia was associated with a significantly worse survival (P = 0.004). CONCLUSION: Our study reveals that anaemia can be a feature of POLG-related disease. Further, we show that its presence is associated with significantly worse prognosis either because anaemia itself is impacting survival or because it reflects the presence of more serious disease. In either case, our data suggests anaemia is a marker for negative prognosis.

Valproic acid-induced hepatotoxicity in Alpers syndrome is associated with mitochondrial permeability transition pore opening-dependent apoptotic sensitivity in an induced pluripotent stem cell model.

UNLABELLED: Valproic acid (VPA) is widely used to treat epilepsy, migraine, chronic headache, bipolar disorder, and as adjuvant chemotherapy, but potentially causes idiosyncratic liver injury. Alpers-Huttenlocher syndrome (AHS), a neurometabolic disorder caused by mutations in mitochondrial DNA polymerase gamma (POLG), is associated with an increased risk of developing fatal VPA hepatotoxicity. However, the mechanistic link of this clinical mystery remains unknown. Here, fibroblasts from 2 AHS patients were reprogrammed to induced pluripotent stem cells (iPSCs) and then differentiated to hepatocyte-like cells (AHS iPSCs-Hep). Both AHS iPSCs-Hep are more sensitive to VPA-induced mitochondrial-dependent apoptosis than controls, showing more activated caspase-9 and cytochrome c release. Strikingly, levels of both soluble and oligomeric optic atrophy 1, which together keep cristae junctions tight, are reduced in AHS iPSCs-Hep. Furthermore, POLG mutation cells show reduced POLG expression, mitochondrial DNA (mtDNA) amount, mitochondrial adenosine triphosphate production, as well as abnormal mitochondrial ultrastructure after differentiation to hepatocyte-like cells. Superoxide flashes, spontaneous bursts of superoxide generation, caused by opening of the mitochondrial permeability transition pore (mPTP), occur more frequently in AHS iPSCs-Hep. Moreover, the mPTP inhibitor, cyclosporine A, rescues VPA-induced apoptotic sensitivity in AHS iPSCs-Hep. This result suggests that targeting mPTP opening could be an effective method to prevent hepatotoxicity by VPA in AHS patients. In addition, carnitine or N-acetylcysteine, which has been used in the treatment of VPA-induced hepatotoxicity, is able to rescue VPA-induced apoptotic sensitivity in AHS iPSCs-Hep. CONCLUSION: AHS iPSCs-Hep are more sensitive to the VPA-induced mitochondrial-dependent apoptotic pathway, and this effect is mediated by mPTP opening. Toxicity models in genetic diseases using iPSCs enable the evaluation of drugs for therapeutic targets.

Exploring the overlap between multiple sclerosis, tumefactive demyelination and Baló's concentric sclerosis.

The availability of magnetic resonance imaging (MRI) has led to increasing recognition that multiple sclerosis (MS), tumefactive demyelination (TD) and Baló's concentric sclerosis (BCS) share many overlapping features. Baló-like lesions, which exhibit limited features of BCS, may represent an intermediate between BCS and typical MS demyelination. Lesions labeled as tumefactive are typically larger, but otherwise have much in common with conventional MS lesions, and TD and BCS lesions can also overlap. In this article, we explore the similarities between typical MS, TD and BCS cases, and reflect on the potential insights that intermediate or overlapping phenotypes may contribute towards an understanding of MS immunopathogenesis, and question whether these atypical forms of demyelination should be classified as separate demyelinating diseases, as different lesional manifestations of demyelination of any cause or as part of a spectrum with conventional MS.

"Clues on Balo's concentric sclerosis evolution from serial analysis of ADC values".

Balò's sclerosis is considered a rare variant of multiple sclerosis characterized by demyelination with concentric rings. Advanced magnetic resonance studies allow nowadays early diagnosis and prompt treatment. However, the pathophysiology of lesion evolution is still matter of debate, as detailed in our literature review. Based on a clear-cut Balò's lesion analysis, we describe early changes in DWI and ADC values within the different layers, favoring the concept of a centrifugal growth.

A 17-Year-Old Girl With Acute Onset of Hemiparesis.

The presentation of acute-onset hemiparesis in a teenager can be challenging and offers a wide differential diagnosis. We discuss the approach to the patient (which should begin with thorough history taking and physical examination) and advanced imaging as directed by the patient's signs and symptoms. We report the case of an otherwise well 17-year-old girl who presented to the pediatric emergency department with a 2-day history of left-sided weakness and difficulty ambulating. Her eventual diagnosis of Balo concentric sclerosis, a rare form of multiple sclerosis, is discussed.

Yeast cells expressing the human mitochondrial DNA polymerase reveal correlations between polymerase fidelity and human disease progression.

Mutations in the human mitochondrial polymerase (polymerase-γ (Pol-γ)) are associated with various mitochondrial disorders, including mitochondrial DNA (mtDNA) depletion syndrome, Alpers syndrome, and progressive external opthamalplegia. To correlate biochemically quantifiable defects resulting from point mutations in Pol-γ with their physiological consequences, we created "humanized" yeast, replacing the yeast mtDNA polymerase (MIP1) with human Pol-γ. Despite differences in the replication and repair mechanism, we show that the human polymerase efficiently complements the yeast mip1 knockouts, suggesting common fundamental mechanisms of replication and conserved interactions between the human polymerase and other components of the replisome. We also examined the effects of four disease-related point mutations (S305R, H932Y, Y951N, and Y955C) and an exonuclease-deficient mutant (D198A/E200A). In haploid cells, each mutant results in rapid mtDNA depletion, increased mutation frequency, and mitochondrial dysfunction. Mutation frequencies measured in vivo equal those measured with purified enzyme in vitro. In heterozygous diploid cells, wild-type Pol-γ suppresses mutation-associated growth defects, but continuous growth eventually leads to aerobic respiration defects, reduced mtDNA content, and depolarized mitochondrial membranes. The severity of the Pol-γ mutant phenotype in heterozygous diploid humanized yeast correlates with the approximate age of disease onset and the severity of symptoms observed in humans.