Multiple sclerosis and brain tumor: a diagnostic challenge

Multiple Sclerosis and the Choroid Plexus: Emerging Concepts of Disease Immunopathophysiology

BACKGROUND

The coexistence of multiple sclerosis and intracranial neoplasms is very rare, and whether this occurrence can be explained by a causal relationship or by coincidence remains a matter of debate. Possible roles of the choroid plexus as a site of tumor cell invasion and lymphocyte infiltration into the central nervous system have been hypothesized in recent studies.

METHODS

We describe a 13-year-old boy with concurrent multiple sclerosis and choroid plexus papilloma, then review the published literature with a focus on the pathophysiologic mechanisms of neuroinflammation in multiple sclerosis and the potential role of the choroid plexus in this process.

RESULTS

A growing body of evidence suggests that both physical and functional dysregulation of the choroid plexus may be a common mechanism underlying the pathophysiology of central nervous system inflammation.

CONCLUSIONS

In multiple sclerosis, the choroid plexus could act as a gateway for lymphocyte entry from the peripheral blood into the central nervous system at its earlier stages. However, future studies are needed to identify whether structural alterations of the choroid plexus play a role in the pathophysiology of multiple sclerosis and to provide suitable models to determine their consequences.

Inaugural tumor-like multiple sclerosis: clinical presentation and medium-term outcome in 87 patients

BACKGROUND

Tumefactive demyelinating lesions of the central nervous system can be the initial presentation in various pathological entities [multiple sclerosis (the most common), Balo's concentric sclerosis, Schilder's disease and acute disseminated encephalomyelitis] with overlapping clinical presentation. The aim of our study was to better characterize these patients.

METHODS

Eighty-seven patients (62 women and 25 men) from different MS centers in France were studied retrospectively. Inclusion criteria were (1) a first clinical event (2) MRI showing one or more large demyelinating lesions (20 mm or more in diameter) with mass-like features. Patients with a previous demyelinating event (i.e. confirmed multiple sclerosis) were excluded.

RESULTS

Mean age at onset was 26 years. The most common initial symptoms (67% of the patients) were hemiparesis or hemiplegia. Aphasia, headache and cognitive disturbances (i.e. atypical symptoms for demyelinating diseases) were observed in 15, 18 and 15% of patients, respectively. The mean largest diameter of the tumefactive lesions was 26.9 mm, with gadolinium enhancement in 66 patients (81%). Twenty-one patients (24%) had a single tumefactive lesion. During follow-up (median time 5.7 years) 4 patients died, 70 patients improved or remained stable and 12 worsened. 86% of patients received initial corticosteroid treatment, and 73% received disease-modifying therapy subsequently. EDSS at the end of the follow-up was 2.4 ± 2.6 (mean ± SD).

CONCLUSION

This study provides further evidence that the clinical course of MS presenting with large focal tumor-like lesions does not differ from that of classical relapsing-remitting MS, once the noisy first relapsing occurred.

Adult Brain Tumors: Clinical Applications of Magnetic Resonance Spectroscopy

Proton magnetic resonance spectroscopy (H-MRS) may be helpful in suggesting tumor histology and tumor grade and may better define tumor extension and the ideal site for biopsy compared with conventional magnetic resonance (MR) imaging. A multifunctional approach with diffusion-weighted imaging, perfusion-weighted imaging, and permeability maps, along with H-MRS, may enhance the accuracy of the diagnosis and characterization of brain tumors and estimation of therapeutic response. Integration of advanced imaging techniques with conventional MR imaging and the clinical history help to improve the accuracy, sensitivity, and specificity in differentiating tumors and nonneoplastic lesions.

Multifocal Tumefactive Demyelination Mimicking Intracranial Neoplasm

Demyelinating disease presenting with clinical and radiologic features similar to a brain tumour is referred to as tumefactive demyelination. These lesions pose considerable diagnostic uncertainty. This is partly due to the atypical neurologic symptoms that the patient can present with as a consequence of the size, location, and potential for associated mass effect and oedema. The MRI appearance of these lesions can aid in preoperative diagnosis and assist with the final pathologic interpretation. We report a case of tumefactive demyelination where MRI played a vital role in arriving at a diagnosis. The diagnosis was confirmed histopathologically.

Tumefactive demyelinating disease with isolated spinal cord involvement

Tumefactive multiple sclerosis (TMS) is an unusual variant of demyelinating disease. TMS has a variable and unknown progression and presents with features similar to a neoplasm making the determination a diagnostic challenge to clinicians. This report presents one of the very few reported cases of isolated spinal cord TMS, and the second case to describe TMS of the lower spinal cord, given that the lesions are typically cervical. This case study presents a diagnostic approach based on clinical, laboratory, and imaging characteristics, as well as sheds some light on the response to therapy and disease evolution.

Proton MR spectroscopy improves discrimination between tumor and pseudotumoral lesion in solid brain masses

BACKGROUND AND PURPOSE

Differentiating between tumors and pseudotumoral lesions by conventional MR imaging may be a challenging question. This study aims to evaluate the potential usefulness and the added value that single-voxel proton MR spectroscopy could provide on this discrimination.

MATERIALS AND METHODS

A total of 84 solid brain lesions were retrospectively included in the study (68 glial tumors and 16 pseudotumoral lesions). Single-voxel spectra at TE 30 ms (short TE) and 136 ms (long TE) were available in all cases. Two groups were defined: "training-set" (56 cases) and "test-set" (28 cases). Tumors and pseudotumors were compared in the training-set with the Mann-Whitney U test. Ratios between resonances were defined as classifiers for new cases, and thresholds were selected with receiver operating characteristic (ROC) curves. The added value of spectroscopy was evaluated by 5 neuroradiologists and assessed with the Wilcoxon signed-rank test.

RESULTS

Differences between tumors and pseudotumors were found in myo-inositol (mIns); P < .01) at short TE, and N-acetylaspartate (NAA; P < .001), glutamine (Glx; P < .01), and choline (CHO; P < .05) at long TE. Classifiers suggested tumor when mIns/NAA ratio was more than 0.9 at short TE and also when CHO/NAA ratio was more than 1.9 at long TE. Classifier accuracy was tested in the test-set with the following results: short TE, 82% (23/28); long TE, 79% (22/28). The neuroradiologists' confidence rating of the test-cases on a 5-point scale (0-4) improved between 5% (from 2.86-3) and 27% (from 2.25-2.86) with spectroscopy (mean, 17%; P < .01).

CONCLUSIONS

The proposed ratios of mIns/NAA at short TE and CHO/NAA at long TE provide valuable information to discriminate between brain tumor and pseudotumor by improving neuroradiologists' accuracy and confidence.

Characterization of tumefactive demyelinating lesions using MR imaging and in-vivo proton MR spectroscopy

Background and Objectives

Diagnosis of tumefactive demyelinating lesions (TDLs) is challenging to both clinicians and radiologists. Our objective in this study was to analyze and characterize these lesions clinically, biochemically, electrophysiologically, and on imaging.

Methods

A retrospective analysis with prospective follow-up of 18 cases of TDLs was performed. Imaging included T2-, T1-weighted, fluid-attenuated inversion recovery (FLAIR), post-contrast T1-weighted, diffusion weighted imaging (DWI), and proton magnetic resonance spectroscopy (PMRS).

Results

All the lesions appeared hyperintense on T2 and FLAIR images. Increased Apparent diffusion coefficient (ADC) (0.93–2.21 × 10−3 mm2/s) in centre of the lesion was seen in 14/18 cases; however, peripheral restriction (ADC values 0.55–0.64 × 10−3 mm2/s) was noted in 11/18 cases. In all, 13/18 cases showed contrast enhancement with open ring ( n = 5), complete ring ( n = 1), minimal ( n = 4), and infiltrative ( n = 3) pattern of enhancement. Nine of these 13 cases also showed venular enhancement. On PMRS, nine showed glutamate/glutamine (Glx) at 2.4 ppm.

Conclusion

Clinical features along with several MRI characteristics such as open ring enhancement, peripheral restriction on DWI, venular enhancement, and presence of Glx on spectroscopy may be rewarding in differentiating TDLs from neoplastic lesions.

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.

Recurrent tumefactive demyelination in a child

A 13-year-old female presented with two episodes of hemiplegia and hemianopia involving opposite sides, each time associated with seizures. On both occasions, the magnetic resonance (MR) scan showed a giant demyelinating, peripherally enhancing lesion with mass effect. MR spectroscopy (MRS) was indistinguishable from a tumor. At the first episode, she had undergone tumor decompression but the histopathology revealed an acute demyelinating lesion with no evidence of tumor. Each time there was partial clinical recovery and resolution of the radiological lesion, the patient having received corticosteroids during both of the episodes. She also developed hemiballismus postoperatively which resolved on withdrawing phenytoin. It is suggested that a trial of corticosteroids be given in suspected tumefactive demyelinating lesions, although they may be indistinguishable from a tumor.

Late-onset multiple sclerosis mimicking brain tumor: a case report

Multiple sclerosis (MS) is a demyelinating disease that predominantly affects those aged in their twenties to their forties. We recently observed a case of rapidly progressive late-onset MS in an elderly patient with a large, single lesion on magnetic resonance imaging (MRI), which was difficult to distinguish from a brain tumor. This case is reported here with a review of the literature. A 69-year-old woman who presented with left hemiparesis was admitted to our institute. A tumor lesion was strongly suspected from the MRI finding of a large solitary lesion adjacent to the right lateral ventricle. Her left hemiparesis became rapidly worse, so we decided to perform stereotactic biopsy. Histopathological examination indicated that the patient had a demyelinating disease such as multiple sclerosis. Steroid pulse therapy was started after the operation and led to a marked improvement of the symptoms. With follow-up for more than 1 year after discharge, she has shown no sign of relapse. Late-onset MS should be suspected if edema or mass effect is not visualized around the lesion on MRI, bearing in mind that late-onset MS can have a progressive course in elderly patients.

Pediatric tumefactive demyelination: case series and review of the literature

Tumefactive demyelinating lesions may be misdiagnosed as brain neoplasms or abscesses. In this paper, we present four cases of pediatric tumefactive demyelination. Twelve cases of pediatric tumefactive demyelination previously reported in the English literature are also summarized. We describe the neuroimaging characteristics and clinical presentation of tumefactive demyelination and how these features may be used in differentiating demyelination from other mass lesions.

In vivo differentiation of astrocytic brain tumors and isolated demyelinating lesions of the type seen in multiple sclerosis using 1H magnetic resonance spectroscopic imaging

We used computer pattern recognition of proton magnetic resonance spectroscopic image data to differentiate between brain tumors and large, isolated, demyelinating lesions of the type seen in multiple sclerosis. Leave-one-out linear discriminant analyses correctly classified resonance profiles from five acute demyelinating lesions, 20 low-grade astrocytomas, 22 anoplastic astrocytomas, and 24 glioblastomas. Classification of nonacute lesions will require further development, as the metabolic profiles of demyelinating lesions evolve over time.

MR imaging of multiple sclerosis simulating brain tumor

Multiple sclerosis may sometimes present as a mass lesion that is indistinguishable from brain tumor both clinically and radiologically. We describe two cases of multiple sclerosis simulating brain tumor on computed tomography (CT) scans and magnetic resonance (MR) images, one of which was proved and another was suggestive to be demyelinating disease by biopsy. Steroid therapy produced regression of the lesions of MR images and CT scans. Our cases and others in the literature suggest strategies for detecting multiple sclerosis presenting as a mass lesion.

Multiple sclerosis masquerading as a mass lesion

Six patients presenting with new neurological deficits underwent magnetic resonance imaging (MRI) that displayed mass lesions leading to diagnoses of tumor or abscess. Biopsy revealed demyelinating lesions.