Acute demyelination, neuropathological diagnosis, and clinical evolution

Tumefactive demyelinating disorders as stroke mimics: Description of cases and systematic review of the literature

BACKGROUND

tumefactive multiple sclerosis (TmMS) is a rare subtype of a demyelinating disease that develops over time. Cases of hyperacute presentations mimicking cerebrovascular disorders have been reported; however, detailed clinical and demographic data are lacking.

METHODS

this study aimed to systematically review the literature on tumefactive demyelinating disorders presenting as strokes. After screening the PubMed, PubMed Central, and Web of Science databases, 39 articles describing 41 patients were identified, including 2 historical patients from our center.

RESULTS

23 (53.4%) patients were diagnosed with multiple sclerosis variants (vMS), 17 (39.5%) with inflammatory demyelinating variants (vInf), and 3 with tumors; however, only 43.5% of cases were verified histologically. In subgroup analysis, vMS differed from vInf in several aspects. Inflammatory cerebral spinal fluid parameters, including pleocytosis, proteinorachia was more commonly observed in vInf [11 (64.7%) vs. 1 (5.2%), P = 0.001 and 13/17 (76.4%) vs. 6/23 (31.5%), P = 0.02] than that in vMS. Neurological deterioration and fatal outcomes were more commonly observed in vInf [13/17 (76.4%) vs. 7/23 (30.4%), P = 0.003, and 11/17 (64.7%) vs. 0/23 (0%), P = 0.0001] than that in vMS.

CONCLUSIONS

Clinicodemographic data might aid in recognizing different subtypes of TmMS and warrant consideration of unconventional therapies because outcomes may be poor in the vInf of TmMS.

Integrative and comparative single-cell analysis reveals transcriptomic difference between human tumefactive demyelinating lesion and glioma

Tumefactive demyelinating lesion (TDL) is an immune-mediated disease which can be misdiagnosed as glioma. At present, there is no study comparing difference between the two disorders at the cellular level. Here, we perform integrative and comparative single-cell RNA sequencing (ScRNA-seq) transcriptomic analysis on TDL and glioma lesions. At single-cell resolution, TDL is comprised primarily of immune cells, which is completely different from glioma. The integrated analysis reveals a TDL-specific microglial subset involving in B cell activation and proliferation. Comparative analysis highlights remyelination function of glial cells and demyelination function of T cells in TDL. Subclustering and pseudotime trajectory analysis of T cells in TDL reveal their heterogeneity and diverse functions involving in TDL pathogenesis and recovery process. Our study identifies substantial differences between TDL and glioma at single-cell resolution. The observed heterogeneity and potentially diverse functions of cells in TDL may be critical in disease progression.

Integrative and comparative single-cell analysis reveals transcriptomic difference between human tumefactive demyelinating lesion and glioma.

Tumor-Like Multiple Sclerosis: Report of Four Cases and Literature Review

Aims and background

Classical multiple sclerosis plaques usually have typical features on gadolinium-enhanced MRI scan. This non-neoplastic demyelinating process of the central nervous system generally does not produce focal space-occupying lesions associated with ring enhancement. However, atypical appearance of demyelinating lesions simulating a brain tumor is a possible well-known phenomenon.

Methods

We present our experience with 4 cases of multiple sclerosis indistinguishable clinically and neuroradiologically from a cerebral tumor. All patients underwent surgery.

Results

Histological examinations of all cases were positive for multiple sclerosis plaques.

Conclusions

The presented cases demonstrate the importance of considering a demyelinating disease in the differential diagnosis of a tumor-like brain lesion.

Acute multiple sclerosis lesion pathology does not predict subsequent clinical course-a biopsy study

BACKGROUND

Knowledge of the clinical outcome in tumefactive demyelination remains limited.

AIMS

This study aims to characterise the natural history of biopsy-proven, pathogen-free, cerebral demyelination in an adult Irish population.

METHODS

We identified all patients with biopsy-proven demyelination in a single neuropathology centre between 1999 and 2017. A baseline, and at least one follow-up MRI scan was available in each instance (mean of 3 scans per patient), together with both the presenting and most recent clinical details including disability level and disease-modifying drugs.

RESULTS

In 21 patients, white matter biopsies showed the following: macrophages with myelin debris, myelin-axonal dissociation, reactive astrocytes and occasional lymphocytes. During a mean follow-up time of 8 years (± 4.4), 17 patients developed MS, confirmed both clinically and on MRI, using the 2010 McDonald criteria: 11 relapsing remitting (RR) MS, four secondary progressive and two primary progressive MS. Four patients had a monophasic illness with lesion regression, without clinical or radiological evidence of any further disease activity on follow-up. The patients with progressive MS had significantly higher levels of physical disability than either the RRMS or monophasic patients.

CONCLUSION

Uniform white matter subacute demyelination is associated with a diverse clinical course ranging from a monophasic illness to progressive MS, suggesting that extraneous factors distinct from the basic pathology significantly influence the clinical course in MS.

The Role of Neurosurgery in the Treatment of Intracranial Tumor-Like Inflammatory Lesions

BACKGROUND

Different inflammatory diseases can manifest as intracranial lesions. They may be indistinguishable from intracranial neoplasms in the clinical setting, imaging studies, or laboratory studies. The value of surgery in the diagnosis and the treatment of such lesions is still unclear.

METHODS

A total of 3066 reports of histopathologic examinations over a 10-year period were reviewed. Forty patients with an inflammatory intracranial lesion were identified. Clinical, radiologic, and follow-up data were analyzed and the diagnostic and therapeutic value of surgery was assessed.

RESULTS

We identified 24 women and 16 men (mean age, 47 years). The diameter of the lesion varied between 1 and 5.5 cm (mean, 2.6 cm). The location of the inflammatory lesion was intracerebral supratentorial (n = 18, 45%), intrasellar/suprasellar (n = 5, 12.5%), cerebellar (n = 5, 12.5%), in the brainstem (n = 4, 10%), in the cerebellopontine angle (n = 3, 7.5%), meningeal (n = 3, 7.5%), and at other locations (n = 6, 15%). Seventeen patients underwent surgical removal of the mass lesion, whereas in 23 patients a biopsy was taken. The lesions were classified into 7 groups: specific (infectious) granuloma (n = 10, 25%), unspecific granuloma (n = 7, 17.5%), idiopathic inflammatory pseudotumor (n = 5, 12.5%), demyelinating lesions (n = 5, 12.5%) encapsulated hematoma (n = 4, 10%), organized cerebral infarction (n = 3, 7.5%), and vasculitis (n = 4, 10%). Surgery was judged as valuable in 35 patients (87.5%).

CONCLUSIONS

The differential diagnosis of intracranial inflammatory lesions involves a wide spectrum. Surgery has a diagnostic and/or therapeutic value in most entities and clinical circumstances. However, attention must be taken to avoid surgery without a therapeutic or diagnostic value for the patient.

Value of 18F-FET PET in Patients With Suspected Tumefactive Demyelinating Disease-Preliminary Experience From a Retrospective Analysis

PURPOSE

To investigate the diagnostic value of F-fluoroethyl-L-tyrosine (FET) positron emission tomography (PET) in patients with suspected tumefactive demyelinating disease.

METHODS

We retrospectively examined FET-PET and MR imaging of 21 patients (12 female, 9 male) with known demyelinating disease and newly diagnosed tumefactive lesions. The maximum standardized uptake value (SUVmax), time activity curves (TAC) and lesion-to-background ratio (TBR) of these lesions were calculated. The standard of reference consisted of biopsy and/or follow-up imaging. FET parameters of true neoplastic lesions and tumefactive demyelinating lesions were compared using Mann-Whitney U-test and receiver operating characteristic (ROC) analysis.

RESULTS

Nine patients (42.9%) had neoplastic lesions, 12 patients (57.1%) had tumefactive demyelinating lesions. TBRmax, SUVmax and TAC were significantly different between demyelinating lesions and neoplastic lesions: Tumors had a higher TBRmax (3.53 ± 1.09 vs. 1.48 ± 0.31, respectively; P < 0.001) and SUVmax (3.95 ± 1.59 vs. 1.86 ± 0.50, respectively; P < 0.001) than tumefactive demyelinating lesions. The TAC of tumors was significantly higher compared to tumefactive demyelinating lesions at all time points (P < 0.05). ROC analysis revealed that a TBRmax threshold of 2.2 and a SUVmax threshold of 2.5 could reliably differentiate tumor and tumefactive demyelination (area under the curve, 1.000 and 0.958, respectively).

CONCLUSION

In patients with demyelinating disease, FET-PET parameters TBRmax (cut-off 2.2) and SUVmax (cut-off 2.5) are able to distinguish tumefactive demyelinations from true neoplastic lesions.

Occurrence and long-term outcome of tumefactive demyelinating lesions in multiple sclerosis

Although tumefactive multiple sclerosis is a well recognized variant of multiple sclerosis, prognostic uncertainty still exists about long term prognosis. The aim of this study was to estimate the occurrence and long term outcome of tumefactive demyelinating lesions (TDLs) in a cohort of multiple sclerosis patients. We reviewed brain MRI of 443 patients referred to our MS clinic. All patients meeting the McDonald criteria for multiple sclerosis and showing at least one TDL were included. Kaplan-Meier estimates of disease-free survival in patient cohort were compared with control group without TDLs using a log-rank test. Seven cases with TDLs were identified (occurrence 1.58 %). Tumefactive demyelinating lesion recurrence was 16.6 %. Cumulative proportion of patients free from clinical relapse and from new T2 lesions was lower in the control group although not reaching statistical significance (30 vs 50 %; P = 0.666 and 21.7 vs 33.3 %; P = 0.761, respectively). Disability progression analysis showed a not significant trend towards lower probability of remaining progression free for TDL patients (50 vs 61 %; P = 0.295). Occurrence of tumefactive demyelinating lesions in our cohort was higher than those reported in other studies. Overall, TDLs were not predictive of poor outcome in terms of disability progression.

Benign course of tumour-like multiple sclerosis. Report of five cases and literature review

BACKGROUND

Multiple sclerosis (MS) with initial neuroradiological features suggestive of brain tumour (tumour-like MS) may represent a challenging diagnosis.

METHODS

Among the patients seen at the MS centre of our Institution between 2000 and 2010, we identified cases presenting with a large (diameter>2 cm), well-defined lesion, suggestive of brain tumour on initial brain magnetic resonance imaging (MRI). Only patients with at least 10 years follow-up were included.

RESULTS

Five young women with MS who presented with a tumour-like lesion on initial brain MRI are described. All cases presented with sudden-onset neurological deficits due to a single large brain lesion compatible with neoplasm at MRI. Two cases underwent brain stereotactic biopsy, both misdiagnosed as astrocytoma. However, the subsequent clinical and MRI follow-up was consistent with MS in all cases. Unnecessary surgery and radiotherapy were responsible for disability in two cases. In three cases, the course of the disease remains benign after more than 13 years from symptoms onset.

CONCLUSIONS

Our report of clinical, radiological and pathological features of five tumour-like MS cases confirms that it is mandatory to consider a demyelinating process in the differential diagnosis of tumour-like brain lesions. Many tumour-like MS cases may have a favourable long term prognosis.

Diffusion-weighted imaging characteristics of biopsy-proven demyelinating brain lesions

OBJECTIVES

To describe lesional diffusion-weighted imaging characteristics in a cohort of patients with biopsy-proven CNS inflammatory demyelinating disease (IDD) and compare diffusion characteristics of ring-enhancing CNS IDD lesions vs abscesses and tumors.

METHODS

Forty prebiopsy apparent diffusion coefficient (ADC) maps were reviewed from 30 patients with CNS IDD. Lesions were analyzed for size, T2-weighted (T2W) hypointense rim, enhancement, and ADC pattern. ADC patterns of CNS IDD ring-enhancing lesions were compared with a published cohort of 35 patients with ring-enhancing tumors and abscesses.

RESULTS

IDD lesions displayed a spectrum of peripheral ADC patterns at the lesion edge: restricted diffusion (low ADC), 33%; increased diffusion (high ADC), 60%; and normal diffusion (homogeneously isointense), 7%. Of biopsied lesions, 93% enhanced (ring, 52%; heterogeneous, 34%; homogeneous, 7%). A hypointense T2W rim was observed in 53%. A ring pattern on ADC (isointense or dark) was associated with T2W hypointense rims (p = 0.02) but not with ring enhancement. On serial imaging, 4 of 7 (57%) patients demonstrated changes in ADC patterns. Peripheral restriction was more common in IDD (p = 0.006) than in tumors or abscesses, whereas central restriction was only observed in abscesses. Restricted lesions in the same stage were more common in the non-IDD cohort (42% vs 20%), with a uniform restricted pattern seen only in abscesses.

CONCLUSIONS

In ring-enhancing lesions, peripheral diffusion restriction is more common in IDD than in tumors/abscesses, whereas central restriction is more common among abscesses. Rapid ADC pattern changes in IDD probably reflect dynamic lesion evolution and may distinguish IDD from tumors.

Perfusion CT imaging of brain tumors: an overview

Perfusion imaging of brain tumors has been performed by using various tracer and nontracer modalities and can provide additional physiologic and hemodynamic information, which is not available with routine morphologic imaging. Tumor vascular perfusion parameters obtained by using CT or MR perfusion have been used for tumor grading, prognosis, and treatment response in addition to differentiating treatment/radiation effects and non-neoplastic lesions from neoplasms. This article is an overview of the utility of PCT for assessment of brain tumors and describes the technique, its advantages, and limitations.

Pseudoneoplasms of the Nervous System

Context.—Pseudoneoplasms of the nervous system vary greatly in nature. Ranging from inflammatory to autoimmune, infectious, malformative, reactive, degenerative, and radiation induced, they all mimic true tumors. Thus, they have the potential to mislead clinicians, radiologists, and pathologists alike. Their clinical and/or neuroimaging and histologic features are readily misinterpreted as tumor. Knowledge of the pitfalls is essential to avoid mismanagement, specifically overtreatment. In such instances, pathologists must take the entire clinical picture into consideration, acquainting themselves with presenting symptoms, physical findings, and neuroimaging.

Objective.—To present 10 examples of pseudoneoplasms of the nervous system, analyze the basis for their mimicry, and discuss their differential diagnosis.

Data Sources.—Review of the pertinent literature related to pseudoneoplasms of the nervous system and review of the consultation files of one of the authors (B.W.S.).

Conclusions.—The identification of tumor mimics may be difficult under the best of circumstances, and maintaining a broad differential diagnosis as well as application of a variety of immunocytochemical and occasionally ultrastructural and/or molecular genetic methods is essential to arrive at a correct diagnosis.

Can permeability measurements add to blood volume measurements in differentiating tumefactive demyelinating lesions from high grade gliomas using perfusion CT?

Tumefactive demyelinating lesions (TDLs) can mimic a neoplasm on conventional imaging and may necessitate biopsy for diagnosis. The purpose of this study was to differentiate TDLs from high grade gliomas based on physiologic (permeability) and hemodynamic (blood volume) parameters using perfusion CT. Five patients who presented with tumefactive enhancing lesions on initial MRI that mimicked a neoplasm underwent perfusion CT. We compared the perfusion CT parameters of these patients with those of 24 patients with high grade gliomas. TDLs showed lower permeability surface area product (PS) (0.8 +/- 0.2 vs 2.4 +/- 1.4 ml/100 g/min, P-value 0.014) and lower cerebral blood volume (CBV) (1.0 +/- 0.2 vs 2.8 +/- 1.2 ml/100 g, P-value 0.006) as compared to high grade gliomas. TDLs show lower PS and CBV as compared to high grade gliomas, to which they can mimic on conventional MR imaging, due to lack of neoangiogenesis and vascular endothelial proliferation and hence perfusion CT can be used to differentiate the two entities.

Clinical and radiographic spectrum of pathologically confirmed tumefactive multiple sclerosis

Atypical imaging features of multiple sclerosis lesions include size >2 cm, mass effect, oedema and/or ring enhancement. This constellation is often referred to as ‘tumefactive multiple sclerosis’. Previous series emphasize their unifocal and clinically isolated nature, however, evolution of these lesions is not well defined. Biopsy may be required for diagnosis. We describe clinical and radiographic features in 168 patients with biopsy confirmed CNS inflammatory demyelinating disease (IDD). Lesions were analysed on pre- and post-biopsy magnetic resonance imaging (MRI) for location, size, mass effect/oedema, enhancement, multifocality and fulfilment of Barkhof criteria. Clinical data were correlated to MRI. Female to male ratio was 1.2 : 1, median age at onset, 37 years, duration between symptom onset and biopsy, 7.1 weeks and total disease duration, 3.9 years. Clinical course prior to biopsy was a first neurological event in 61%, relapsing–remitting in 29% and progressive in 4%. Presentations were typically polysymptomatic, with motor, cognitive and sensory symptoms predominating. Aphasia, agnosia, seizures and visual field defects were observed. At follow-up, 70% developed definite multiple sclerosis, and 14% had an isolated demyelinating syndrome. Median time to second attack was 4.8 years, and median EDSS at follow-up was 3.0. Multiple lesions were present in 70% on pre-biopsy MRI, and in 83% by last MRI, with Barkhof criteria fulfilled in 46% prior to biopsy and 55% by follow-up. Only 17% of cases remained unifocal. Median largest lesion size on T2-weighted images was 4 cm (range 0.5–12), with a discernible size of 2.1 cm (range 0.5–7.5). Biopsied lesions demonstrated mass effect in 45% and oedema in 77%. A strong association was found between lesion size, and presence of mass effect and/or oedema (P< 0.001). Ring enhancement was frequent. Most tumefactive features did not correlate with gender, course or diagnosis. Although lesion size >5 cm was associated with a slightly higher EDSS at last follow-up, long-term prognosis in patients with disease duration >10 years was better (EDSS 1.5) compared with a population-based multiple sclerosis cohort matched for disease duration (EDSS 3.5; P< 0.001). Given the retrospective nature of the study, the precise reason for biopsy could not always be determined. This study underscores the diagnostically challenging nature of CNS IDDs that present with atypical clinical or radiographic features. Most have multifocal disease at onset, and develop RRMS by follow-up. Although increased awareness of this broad spectrum may obviate need for biopsy in many circumstances, an important role for diagnostic brain biopsy may be required in some cases.

MRI characteristics of atypical idiopathic inflammatory demyelinating lesions of the brain : A review of reported findings

BACKGROUND

Idiopathic inflammatory demyelinating lesions (IIDL) of the brain usually present with a morphologic pattern characteristic of multiple sclerosis (MS). Atypical appearances of IIDLs also exist, however, and can pose significant diagnostic problems and uncertainty regarding prognosis and adequate therapy. We attempted to improve upon this situation by reviewing the literature.

METHODS

We performed a PubMed search from January 1984 through December 2004 for articles in English reporting on IIDLs which had been considered as morphologically atypical (66 articles; 270 cases reported). From these publications 69 individual patient reports allowed the extraction of adequate information on magnetic resonance imaging (MRI) and associated disease characteristics.

RESULTS

Reported atypical IIDLs most frequently manifested as large ring-like lesions (n = 27) which are now considered quite suggestive of an antibodymediated form of MS. Truly atypical IIDLs were less common and exhibited appearances which we termed megacystic (n = 8), Balolike (n = 11) and diffusely infiltrating (n = 11). Despite limitations imposed by the absence of original data the inter-rater agreement in defining these subtypes of atypical IIDLs was moderate to substantial (kappa 0.48-0.68) and we noted trends for their association with certain demographic, clinical and paraclinical variables.

INTERPRETATION

We suggest that IIDLs reported as atypical in the literature can be segregated into several distinct subtypes based on their MRI appearance. The recognition of these patterns may be useful for the differential diagnosis and for a future classification. Because of the limitations inherent in our review this will have to be confirmed by a prospective registry.

Tuberculous encephalopathy: a reappraisal

Forty years ago Dastur and Udani described a form of diffuse cerebral damage in tuberculosis, which they called tuberculous encephalopathy. Their pathological and clinical observations led them to propose an immune pathogenesis. Although there have been no convincing independently reported series, the entity is now established in the tuberculosis literature. We review the literature on tuberculous encephalopathy, and suggest alternative aetiopathogenetic explanations for the appearances of the brain in these cases. We propose that tuberculosis is one of many infections which may be associated with a range of immune, drug-related, hypoxic-ischaemic and toxic diffuse brain pathologies.

Tumefactive demyelinating lesions: conventional and advanced magnetic resonance imaging

In rare instances, demyelinating disorders present with radiological features that mimic a brain tumour. This often leads to biopsy, which--apart from carrying significant morbidity--frequently turns out as nondiagnostic or dispensable. We therefore set out to assess the contribution of repeated conventional magnetic resonance imaging (MRI), 1H-MR spectroscopy and magnetization transfer imaging in establishing a correct diagnosis of tumefactive demyelinating lesions (TDLs). We studied two females and one male, who presented with TDLs that led to brain biopsy in two cases, for up to three years. TDLs were characterized by the following features: (a) delayed or absent response to high-dose steroids together with progressive lesion growth over several weeks; (b) late or sparse enhancement, ill-defined borders, signal inhomogeneity and considerable concomitant oedema; and (c) normalization of initial increases in lipid and lactate peaks within three to four weeks, followed by persistent, marked reductions of the neuronal marker NAA and MTR values around or below 30%. These imaging characteristics reflected the histological correlate of marked demyelination in the absence of significant inflammation. MRI techniques thus appear to have the potential to establish a correct diagnosis of this subtype of TDLs. Awareness of these possibilities might obviate the need for biopsy at least in some cases in future.

Functional imaging of a large demyelinating lesion

PURPOSE

To determine the metabolic characterization of a large solitary demyelinating lesion.

METHODS

Magnetic Resonance Spectroscopy (MRS) and Positron Emission Tomography (PET) studies with 2-deoxy-2-[F-18]fluoro-d-glucose (FDG), carbon-11-methionine (methionine) and carbon-11-choline (choline) were done on the demyelinating lesion.

RESULTS

The demyelinating lesion exhibited a low glucose uptake, prominent methionine uptake and a minimal choline uptake on the PET studies. MRS data revealed an increased choline to creatine (cho/cr) ratio and a decreased N-acetyl-aspartate to creatine (NAA/cr) ratio, which demonstrated a return to near normal ratios on follow-up study.

CONCLUSION

The report summarizes the metabolic characteristics of a demyelinating plaque.

Multinucleated astrocytes in old demyelinated plaques in a patient with multiple sclerosis

A 51-year-old woman with MS of 26 years duration is reported. The patient's MS history began at the age of 25 years with an initial relapsing-remitting course, followed by slow progression without distinct relapses. She became bed-ridden at the age of 40 years. A post-mortem examination revealed numerous demyelinated plaques that exhibited fibrillary gliosis with Rosenthal fibers, but without lymphocytic cuffing or foamy macrophages. Activated microglia were found mainly in the marginal portion of the plaques. These plaques were consistent with so-called 'slowly expanding plaques'. Interestingly, multinucleated astrocytes were observed within the plaques, being more numerous in the area where microglial infiltration had occurred. These findings suggest that mild persistent inflammatory processes are present even in old plaques and that certain inflammatory stimuli cause multinucleation of astrocytes. This might explain the gradual deterioration without definite relapses observed in the late stage of MS.

Monophasic, solitary tumefactive demyelinating lesion: neuroimaging features and neuropathological diagnosis

The characteristic clinicoradiological findings of multiple sclerosis and acute disseminated encephalomyelitis (ADEM), demonstrating a recurrent progressive course in the former and monophasicity in the latter associated with multiple discrete white matter lesions with variable enhancement on MRI, are not a diagnostic challenge. On the other hand, the less typical radiological presentation of a solitary tumefactive demyelinating lesion mimics a neoplasm, and often necessitates a biopsy. Nonetheless, histopathological examination is an imperfect gold standard and the recognition of certain imaging features may facilitate the correct diagnosis.

Acute focal demyelinating disease simulating brain tumors: histopathologic guidelines for an accurate diagnosis

The object of the present study was to determine the histopathological guidelines for accurate diagnosis of cases of acute focal demyelinating disease that simulates brain tumors. The surgical pathology of three such cases is assessed. Histopathological keys to the diagnosis of such cases are as follows. First, a pattern of sheets of atypical gemistocytic astrocytes in the white matter that show well-formed processes and that are adequately distanced from each other argues against a diagnosis of neoplasm. Second, uniform distribution of foamy macrophages aligned along axons, with occasional focal collections surrounding blood vessels and in the absence of any associated coagulative necrosis argues against the presence of a tumor. Third, perivascular chronic inflammatory infiltration, especially a mixture of lymphocytes and macrophages, favors the diagnosis of demyelination plaque. In such cases the lymphocytes will be predominantly T cells. Fourth, pleomorphic astrocytic proliferation with a lack of vascular endothelial proliferation should raise the suspicion that the lesion may not be a brain tumor. These diagnostic keys should be followed when diagnosing cases that are suspected to be demyelination processes rather than brain tumors. The presence of demyelination plaque should then be confirmed by imaging modalities such as staining with myelin-and axon-specific stains.