Tumefactive demyelinating lesions: conventional and advanced magnetic resonance imaging

Kidney Transplant Recipient With Tumefactive Demyelinating Lesions: A Case Report and Literature Review

Tumefactive demyelinating lesions (TDLs) are rare and specific types of inflammatory demyelinating lesions. Its clinical manifestations are nonspecific, and the imaging findings are similar to those of other intracranial space-occupying lesions, which are usually misdiagnosed as tumors or abscesses and require a pathologic examination to confirm the diagnosis. Tumefactive demyelinating lesions after kidney transplantation are even rarer. This article reports a case of TDLs after kidney transplantation. A 60-year-old female patient underwent kidney transplantation 15 years ago and took anti-rejection drugs such as tacrolimus, tacrolimus, and corticosteroids after surgery. The patient was admitted with headache and left limb weakness, and magnetic resonance imaging of the head showed multiple space-occupying lesions with surrounding edema. The patient underwent a stereotactic biopsy of the encephalopathy lesion, and postoperative pathology confirmed TDLs. She was treated with corticosteroids and discharged after the improvement of her symptoms. Here, to our knowledge, we report the first case of TDLs after kidney transplantation. We report this case to provide clinicians with useful information on intracranial demyelinating disease after kidney transplantation.

Additional Diagnostic Value of Unenhanced Computed Tomography plus Diffusion-Weighted Imaging Combined with Routine Magnetic Resonance Imaging Findings of Early-Stage Gliblastoma

PURPOSE

This study was performed to determine whether diffusion-weighted imaging (DWI) plus unenhanced computed tomography (CT) of the brain increases the diagnostic value of routine magnetic resonance (MR) imaging findings of early-stage glioblastoma.

METHODS

Postcontrast MR images of eight unenhanced lesions that had been pathologically diagnosed as glioblastoma were retrospectively examined. The location, margin, signal intensity, and attenuation on MR imaging and CT were assessed.

RESULTS

On MR imaging, all lesions were ill-defined, small, and isointense to hypointense on T1-weighted images and hyperintense on T2-weighted images. Four patients had perilesional edema. In seven patients, DWI showed an inhomogeneous hyperintense lesion (n = 1) or isointense lesion with a hyperintense region (n = 1) or isointense lesion with a hyperintense region (n = 1) or isointense lesion with a hyperintense region (n = 1) or isointense lesion with a hyperintense region (n = 1) or isointense lesion with a hyperintense region (n = 1) or isointense lesion with a hyperintense region (n = 1) or isointense lesion with a hyperintense region (n = 1) or isointense lesion with a hyperintense region (n = 1) or isointense lesion with a hyperintense region (.

CONCLUSIONS

MR imaging was the most sensitive imaging method for depicting early-stage glioblastoma. The CT finding of a hyperattenuated or isoattenuated region combined with the DWI finding of the same region containing an inhomogeneous hyperintense lesion or isointense lesion with a hyperintense region may be a specific diagnostic sign for early-stage glioblastoma. DWI plus unenhanced CT added diagnostic value to the routine MR imaging findings of early-stage glioblastoma.

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.

Primary CNS Lymphomas: Challenges in Diagnosis and Monitoring

Primary Central Nervous System Lymphoma (PCNSL) is a rare neoplasm that can involve brain, eye, leptomeninges, and rarely spinal cord. PCNSL lesions most typically enhance homogeneously on T1-weighted magnetic resonance imaging (MRI) and appear T2-hypointense, but high variability in MRI features is commonly encountered. Neurological symptoms and MRI findings may mimic high grade gliomas (HGGs), tumefactive demyelinating lesions (TDLs), or infectious and granulomatous diseases. Advanced MRI techniques (MR diffusion, spectroscopy, and perfusion) and metabolic imaging, such as Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) or amino acid PET (usually employing methionine), may be useful in distinguishing these different entities and monitoring the disease course. Moreover, emerging data suggest a role for cerebrospinal fluid (CSF) markers in predicting prognosis and response to treatments. In this review, we will address the challenges in PCNSL diagnosis, assessment of response to treatments, and evaluation of potential neurotoxicity related to chemotherapy and radiotherapy.

Inflammatory demyelinating diseases of the central nervous system

Inflammatory demyelinating diseases are a heterogeneous group of disorders, which occur against the background of an acute or chronic inflammatory process. The pathologic hallmark of multiple sclerosis (MS) is the presence of focal demyelinated lesions with partial axonal preservation and reactive astrogliosis. Demyelinated plaques are present in the white as well as gray matter, such as the cerebral or cerebellar cortex and brainstem nuclei. Activity of the disease process is reflected by the presence of lesions with ongoing myelin destruction. Axonal and neuronal destruction in the lesions is a major substrate for permanent neurologic deficit in MS patients. The MS pathology is qualitatively similar in different disease stages, such as relapsing remitting MS or secondary or primary progressive MS, but the prevalence of different lesion types differs quantitatively. Acute MS and Balo's type of concentric sclerosis appear to be variants of classic MS. In contrast, neuromyelitis optica (NMO) and spectrum disorders (NMOSD) are inflammatory diseases with primary injury of astrocytes, mediated by aquaporin-4 antibodies. Finally, we discuss the histopathology of other inflammatory demyelinating diseases such as acute disseminated encephalomyelitis and myelin oligodendrocyte glycoprotein antibody-associated demyelination. Knowledge of the heterogenous immunopathology in demyelinating diseases is important, to understand the clinical presentation and disease course and to find the optimal treatment for an individual patient.

Coexistence of Multiple Sclerosis and Brain Tumor: An Uncommon Diagnostic Challenge

Nonneoplastic demyelinating processes of the brain with mass effect on magnetic resonance imaging can cause diagnostic difficulties. It requires differential diagnosis between the tumefactive demyelinating lesion and the coexistence of neoplasm. We document the case of 41-year-old woman with clinical and radiological findings suggestive of multiple sclerosis. Additional investigations confirmed the coexistence of astrocytoma. This report emphasizes the importance of considering brain tumors in the differential diagnosis of primary demyelinating disease presenting with a cerebral mass lesion.

Clinicoradiologic features distinguish tumefactive multiple sclerosis from CNS neoplasms

BACKGROUND

There are limited data to guide clinicians in differentiating tumefactive multiple sclerosis (TMS) from CNS neoplasms. Identifying distinguishing features will inform diagnosis and management and avoid unnecessary diagnostic biopsy. Our study aimed to determine the clinical and radiologic features that differentiate TMS from glioma and CNS lymphoma (CNSL) in patients who present with tumefactive lesions.

METHODS

We retrospectively reviewed all patients with tumefactive lesions and histologically proven or clinically diagnosed TMS, glioma, or CNSL at our tertiary center from 1999 to 2012. Two independent blinded neuroradiologists rated MRI brain scans at presentation. We correlated patients' demographic, clinical, laboratory, and radiologic data to final diagnosis.

RESULTS

A total of 133 patients (10 TMS, 85 glioma, 38 CNSL) were analyzed. Patients with TMS were younger and a greater proportion were women. Presenting symptoms did not distinguish between diagnoses. TMS lesions were smaller compared to glioma and CNSL, had no or mild mass effect, and were always associated with contrast enhancement. Radiologic features that were more frequent in TMS lesions were incomplete rim (open-ring) enhancement, incomplete peripheral diffusion restriction, and mixed T2 signal and CT hypoattenuation of MRI-enhancing components (all p < 0.05).

CONCLUSIONS

Radiologic features but not presenting symptoms are useful in distinguishing TMS from CNS neoplasms.

Performance of Apparent Diffusion Coefficient Values and Conventional MRI Features in Differentiating Tumefactive Demyelinating Lesions From Primary Brain Neoplasms

OBJECTIVE

Tumefactive demyelinating lesions (TDLs) remain one of the most common brain lesions to mimic a brain tumor, particularly primary CNS lymphoma (PCNSL) and high-grade gliomas. The purpose of our study was to evaluate the ability of apparent diffusion coefficient (ADC) values and conventional MRI features to differentiate TDLs from PCNSLs and high-grade gliomas.

MATERIALS AND METHODS

Seventy-five patients (24 patients with TDLs, 28 with PCNSLs, and 23 with high-grade gliomas) with 168 brain lesions (70 TDLs, 68 PCNSLs, and 30 high-grade gliomas) who underwent DWI before surgery or therapy were included in the study. Minimum ADC (ADC(min)) and average ADC (ADC(avg)) values were calculated for each lesion. ANOVA and ROC analyses were performed. ROC analyses were also performed for the presence of incomplete rim enhancement and for the number of lesions. Multiple-variable logistic regression with ROC analysis was then performed to evaluate performance in multiple-variable models.

RESULTS

ADC(min) was statistically significantly higher (p < 0.01) in TDLs (mean, 0.886; 95% CI, 0.802-0.931) than in PCNSLs (0.547; 95% CI, 0.496-0.598) and high-grade gliomas (0.470; 95% CI, 0.385-0.555). (All ADC values in this article are reported in units of × 10(-3) mm(2)/s.) ADC(avg) was statistically significantly higher (p < 0.01) in TDLs (mean, 1.362; 95% CI, 1.268-1.456) than in PCNSLs (0.990; 95% CI, 0.919-1.061) but not in high-grade gliomas (1.216; 95% CI, 1.074-1.356). Multiple-variable models showed statistically significant individual effects and superior diagnostic performance on ROC analysis.

CONCLUSION

TDLs can be diagnosed on preoperative MRI with a high degree of specificity; MRI features of incomplete rim enhancement, high ADC values, and a large number of lesions individually increase the probability and diagnostic confidence that a lesion is a TDL.

A case of tumor-like inflammatory demyelinating disease with progressive brain and spinal cord involvement

CONTEXT

Tumor-like inflammatory demyelinating disease (TIDD) usually occurs in the brain and rarely occurs in the spinal cord. TIDD appears to be very similar to tumors such as gliomas on imaging, which may lead to incorrect or delayed diagnosis and treatment.

CASE REPORT

Because of headache and incoherent speech, a 24-year-old Chinese male presented to our hospital with a two-week history of respiratory infections. After dexamethasone treatment, his symptoms still got worse and surgery was performed for diagnostic purposes. Histological examination revealed that the lesion was inflammatory. Further lesions appeared in the spine (T3 and T4 levels) after two months and in the right occipital lobe after three months. After intravenous immunoglobulin (IVIG) and methylprednisolone treatment, his symptoms improved.

CONCLUSION

Progressive lesions may damage the brain and spinal cord, and long-term prednisolone and IVIG therapy are beneficial in TIDD patients.

Cerebral tumefactive demyelinating lesions

Tumefactive demyelinating lesions (TDLs), are a rare demyelinating pathological disease in the central neurological system, which have been proven to be a diagnostic dilemma to neurosurgeons. The clinical presentation and radiographic appearance of these lesions often results in their misdiagnosis as intracranial tumors, such as gliomas, which leads to unnecessary surgical resection and adjunct radiation. In the present study, the clinical and radiographic features of 14 patients with cerebral TDLs who underwent surgical treatment between January 2004 and January 2009 were reviewed and analyzed. The surgical methods used included biopsy and resection, while steroid therapy was indicated when TDLs were confirmed by histopathological analysis. The patients were followed-up and the outcomes were evaluated using the Karnofsky performance scale (KPS). The main clinical presentations included: Hemiplegia (8 cases), increased intracranial pressure (4 cases) and seizures (general in 1 case; partial in 3 cases). On magnetic resonance imaging scans, 12/14 TDL cases demonstrated an isolated local subcortical mass and 6/14 cases (42.9%) demonstrated enhancing veins coursing undistorted through the lesion. The postoperative complications included: Hemiplegia (2 cases) and mortality (1 case). A total of 9 cases underwent microsurgical total resection, and 5 cases received stereotactic biopsy that was followed with high-dose methylprednisolone therapy. The follow-up study demonstrated that 2 cases presented recurrence with multiple sclerosis and the KPS scores for 13/14 patients (92.9%) were ≥80. In conclusion, the clinical and radiographic features of TDLs may help to establish the correct diagnosis prior to surgery, in order to avoid unnecessary resection or adjunctive therapy. Using steroid therapy, the majority of patients with TDLs appeared to achieve satisfactory prognosis.

Atypical idiopathic inflammatory demyelinating lesions (IIDL): conventional and diffusion-weighted MR imaging (DWI) findings in 42 cases

INTRODUCTION

The purpose of this study was to evaluate MR imaging characteristics with conventional and advanced MR imaging techniques in patients with IIDL.

METHODS

MR images of the brain in 42 patients (20 male, 22 female) with suspected or known multiple sclerosis (MS) from four institutions were retrospectively analyzed. Lesions were classified into five different subtypes: (1) ring-like lesions; (2) Balo-like lesions; (3) diffuse infiltrating lesions; (4) megacystic lesions; and (5) unclassified lesions. The location, size, margins, and signal intensities on T1WI, T2WI, and diffusion-weighted images (DWI), and the ADC values/ratios for all lesions, as well as the contrast enhancement pattern, and the presence of edema, were recorded.

RESULTS

There were 30 ring-like, 10 Balo-like, 3 megacystic-like and 16 diffuse infiltrating-like lesions were detected. Three lesions were categorized as unclassified lesions. Of the 30 ring-like lesions, 23 were hypointense centrally with a hyperintense rim. The mean ADC, measured centrally, was 1.50 ± 0.41 × 10(-3) mm(2)/s. The mean ADC in the non-enhancing layers of the Balo-like lesions was 2.29 ± 0.17 × 10(-3) mm(2)/s, and the mean ADC in enhancing layers was 1.03 ± 0.30 × 10(-3) mm(2)/s. Megacystic lesions had a mean ADC of 2.14 ± 0.26 × 10(-3)mm(2)/s. Peripheral strong enhancement with high signal on DWI was present in all diffuse infiltrating lesions. Unclassified lesions showed a mean ADC of 1.43 ± 0.13 mm(2)/s.

CONCLUSION

Restriction of diffusion will be seen in the outer layers of active inflammation/demyelination in Balo-like lesions, in the enhancing part of ring-like lesions, and at the periphery of infiltrative-type lesions.

Atypical idiopathic inflammatory demyelinating lesions: prognostic implications and relation to multiple sclerosis

Atypical lesions of a presumably idiopathic inflammatory demyelinating origin present quite variably and may pose diagnostic problems. The subsequent clinical course is also uncertain. We, therefore, wanted to clarify if atypical idiopathic inflammatory demyelinating lesions (AIIDLs) can be classified according to previously suggested radiologic characteristics and how this classification relates to prognosis. Searching the databases of eight tertiary referral centres we identified 90 adult patients (61 women, 29 men; mean age 34 years) with ≥ 1 AIIDL. We collected their demographic, clinical and magnetic resonance imaging data and obtained follow-up (FU) information on 77 of these patients over a mean duration of 4 years. The AIIDLs presented as a single lesion in 72 (80 %) patients and exhibited an infiltrative (n = 35), megacystic (n = 16), Baló (n = 10) or ring-like (n = 16) lesion appearance in 77 (86 %) patients. Additional multiple sclerosis (MS)-typical lesions existed in 48 (53 %) patients. During FU, a further clinical attack occurred rarely (23-35 % of patients) except for patients with ring-like AIIDLs (62 %). Further attacks were also significantly more often in patients with coexisting MS-typical lesions (41 vs. 10 %, p < 0.005). New AIIDLs developed in six (7 %), and new MS-typical lesions in 29 (42 %) patients. Our findings confirm the previously reported subtypes of AIIDLs. Most types confer a relatively low risk of further clinical attacks, except for ring-like lesions and the combination with MS-typical lesions.

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.

Immune mediated diseases and immune modulation in the neurocritical care unit

This chapter will review the spectrum of immune-mediated diseases that affect the nervous system and may result in an admission to the neurological intensive care unit. Immunomodulatory strategies to treat acute exacerbations of neurological diseases caused by aberrant immune responses are discussed, but strategies for long-term immunosuppression are not presented. The recommendations for therapeutic intervention are based on a synthesis of the literature, and include recommendations by the Cochrane Collaborative, the American Academy of Neurology, and other key organizations. References from recent publications are provided for the disorders and therapies in which randomized clinical trials and large evidenced-based reviews do not exist. The chapter concludes with a brief review of the mechanisms of action, dosing, and side effects of commonly used immunosuppressive strategies in the neurocritical care unit.

The next generation of positron emission tomography radiopharmaceuticals in oncology

Although (18)F-fluorodeoxyglucose ((18)F-FDG) is still the most widely used positron emission tomography (PET) radiotracer, there are a few well-known limitations to its use. The last decade has seen the development of new PET probes for in vivo visualization of specific molecular targets, along with important technical advances in the production of positron-emitting radionuclides and their related labeling methods. As such, a broad range of new PET tracers are in preclinical development or have recently entered clinical trials. The topics covered in this review include labeling methods, biological targets, and the most recent preclinical or clinical data of some of the next generation of PET radiopharmaceuticals. This review, which is by no means exhaustive, has been separated into sections related to the PET radionuclide used for radiolabeling: fluorine-18, for the labeling of agents such as FACBC, FDHT, choline, and Galacto-RGD; carbon-11, for the labeling of choline; gallium-68, for the labeling of peptides such as DOTATOC and bombesin analogs; and the long-lived radionuclides iodine-124 and zirconium-89 for the labeling of monoclonal antibodies cG250, and J591 and trastuzumab, respectively.

Characteristic neuroimaging in patients with tumefactive demyelinating lesions exceeding 30 mm

BACKGROUND AND PURPOSE

Features of tumefactive demyelinating lesion (TDL) on magnetic resonance imaging (MRI) can facilitate the differential diagnosis of TDL and neoplastic lesions, but vary considerably among patients. The larger TDL grows, the more difficult it becomes to differentiate TDL from neoplastic lesions. The purpose of this study was to elucidate typical MRI features in 12 patients with large TDL (>30 mm in diameter).

METHODS

We identified 12 patients with large TDL (six men, six women; age range 17-64 years, median age 27 years) and studied the clinical histories and the results of laboratory and various radiological studies in these patients. All cases of clinically definite multiple sclerosis were diagnosed in accordance with McDonald's revised criteria.

RESULTS

Common MRI features of large TDLs included variable degrees of mass effect (71%) and edema (100%), a T2 hypointense rim (79%), venular enhancement (57%), and peripheral restriction on diffusion-weighted images (50%). Ring enhancement (38%), open-ring enhancement (31%), or decreased N-acetylaspartate ratios on magnetic resonance spectroscopy (22%) were less frequently observed. Brain angiography demonstrated venous dilatations on and around the TDL.

CONCLUSIONS

The diagnosis of large TDL is challenging. Our findings suggest that multiple venous dilatations on and around TDLs on angiography can facilitate diagnosis.

Pitfalls in the diagnosis of a tumefactive demyelinating lesion: A case report

Introduction

In rare instances, demyelinating disorders manifest as tumefactive lesions that simulate brain tumors. We report a patient with a space-occupying lesion in the parietal lobe, which presented a serious diagnostic dilemma, between a rare tumefactive demyelinating disease, such as Balo concentric sclerosis and a glioma. This case report highlights important diagnostic clues in the differential diagnosis of Balo concentric sclerosis.

Case presentation

A 20-year-old Caucasian woman with acute onset of left-sided weakness and numbness was admitted to hospital with neurologic signs of left-sided hemiparesis and hypoesthesia. Brain magnetic resonance imaging showed a mass lesion of abnormal signal intensity with concentric enhancing rings in the right parietal lobe, without perifocal edema. The characteristic concentric pattern detected on the magnetic resonance images was highly suggestive of Balo disease, and corticosteroids were administered. Evoked potentials, cerebrospinal fluid analysis, and magnetic spectroscopy findings were not specific, and glioma was also included in the differential diagnosis. A stereotactic biopsy was not diagnostic.

After one month the patient showed moderate clinical improvement, and during 12 months follow-up, no further relapses occurred. In the follow-up magnetic resonance imaging, the concentric pattern had completely disappeared, and only a low-signal, gliotic lesion remained.

Conclusion

We hope this case presentation will advance our understanding of clinical and radiologic appearance of Balo concentric sclerosis, which is a rare demyelinating disease. Although this is a specific entity, it has a broader clinical impact across medicine, because it must be differentiated from other space-occupying lesions in the central nervous system.

Emergent neuroimaging of intracranial infection/inflammation

Infectious and inflammatory processes of the intracranial compartment often result in acute clinical presentations. The possible causes are legion. Clues to the diagnosis involve clinical presentation, laboratory analysis, and neuroimaging. This article reviews some of the salient factors in understanding intracranial infection/ inflammation, including pathophysiology and neuroimaging protocols/findings, and provides some examples and a few "pearls and pitfalls."

Added value and diagnostic performance of intratumoral susceptibility signals in the differential diagnosis of solitary enhancing brain lesions: preliminary study

BACKGROUND AND PURPOSE

It has been reported that high-resolution susceptibility-weighted imaging (HR-SWI) is a promising tool for assessing brain tumor characterization noninvasively. The purpose of this study was to determine the added value and diagnostic performance of HR-SWI for differentiating solitary enhancing brain lesions (SELs) by assessing intratumoral susceptibility signals (ITSSs).

MATERIALS AND METHODS

Sixty-four consecutive patients with SELs, without previous surgery, were retrospectively reviewed. We performed 2 consensus reviews, by using conventional MR images alone and with adjunctive HR-SWI. We applied an ITSS grading system based on the degree of the ITSS. Then, we compared the presence and grade of the ITSSs among specific pathologic types of SELs.

RESULTS

Two observers diagnosed tumor pathology accurately in 43 (67%) of 64 SELs after reviewing the conventional images alone and 50 (78%) of 64 SELs after reviewing the adjunctive HR-SWI (P = .016, McNemar test). ITSSs were seen in 25 (100%) of 25 glioblastoma multiformes (GBMs), in 2 (40%) of 5 anaplastic astrocytomas, and in 11 (73%) of 15 metastatic tumors. Although the ITSSs were unable to distinguish between GBMs and solitary metastatic tumors, differentiation between GBMs and solitary metastatic tumors was achieved (P = .01) by using a high ITSS degree (grade 3). Moreover, the ITSSs could discriminate high-grade gliomas from lymphomas and nontumorous lesions with a specificity of 100% (P < .0001).

CONCLUSIONS

The use of ITSSs on HR-SWIs significantly improves the accuracy for the differential diagnosis of SELs compared with the use of conventional MR imaging alone.

Acute tumefactive demyelinating lesions in a pediatric patient with known diagnosis of multiple sclerosis: review of the literature and treatment proposal

Tumefactive demyelinating lesions are a known but uncommon complication of multiple sclerosis, a disease rarely reported in children. This is the case of a 16-year-old African American patient with multiple sclerosis, who developed 2 tumefactive demyelinating lesions. Review of the literature and our own experience helped formulate an algorithm for therapeutic options during an acute attack.

Tumefactive demyelinating lesions: nine cases and a review of the literature

Tumefactive demyelinating lesions (TDLs) are misdiagnosed frequently. To investigate the characteristics of TDLs, clinical and radiological data from nine cases with TDLs were analyzed after admission. All cases underwent surgery and pathological examination; some received postoperative steroid therapy. Onsets were mostly within 3 weeks and main presentation included intracranial hypertension, extremity weakness, epilepsy, and visual disturbance. Symptoms in children were acute and severe, frequently including headache, vomiting, and visual disturbance. Most intracephalic lesions were in cerebral hemispheres. All intraspinal lesions were in cervical segments. Radiological features included mass effect, perifocal edema and enhancement (of which open-ring enhancement was diagnostic), and decreased relative cerebral blood volume. Intraoperative frozen section did not confirm the diagnosis, while postoperative paraffin section did confirm it (by evidence of macrophage infiltration). The patients responded well to steroid therapy and no relapse was found during following up. Thus, intensive analysis of both clinical and radiological data may provide some clues for diagnosis. For suspected cases, it is advisable to take steroid therapy or undergo advanced radiological examinations, such as serial magnetic resonance spectroscopy. However, in difficult cases, pathological evidence is beneficial to a final diagnosis.

Monofocal large inflammatory demyelinating lesion, mimicking brain glioma

Here we report two cases of pathologically confirmed tumor-like demyelinating lesions. In comparison with common primary demyelinating diseases, our cases demonstrated atypical radiologic features, such as a large monofocal lesion with mild brain edema, and open ring-like or focal enhancement on magnetic resonance images, suggesting brain tumors. The clinical manifestations included focal neurologic signs due to the lesions, monophasic episodes without relapse over a long follow-up period, and efficacy of oral corticosteroid therapy. Histological analysis of brain biopsy specimens showed the inflammatory demyelination and preserved axons without tumor cells. The present cases suggest the importance of considering inflammatory demyelinating disease in the different diagnosis of monofocal tumor-like lesion.

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.

Solitary Brain Lesions Enhancing at MR Imaging: Evaluation with Fluorine 18–Fluorocholine PET

PURPOSE

To prospectively determine whether differences between benign and malignant brain lesions can be depicted with fluorine 18 ((18)F) fluorocholine positron emission tomography (PET).

MATERIALS AND METHODS

Thirty consecutive patients (14 women, 16 men; age range, 26-79 years) with solitary brain lesions that were enhanced at magnetic resonance (MR) imaging underwent whole-brain (18)F-fluorocholine PET after giving informed consent in this institutional review board-approved, HIPAA-compliant study. Histopathologic diagnoses were made in 24 cases (13 high-grade gliomas, eight metastases to the brain, and three benign lesions). In six cases, benign lesions were diagnosed on the basis of longitudinal follow-up MR findings. The maximum standardized uptake value (SUV(max)) for lesion and peritumoral regions was measured on PET images, and a lesion-to-normal tissue uptake ratio (LNR) was calculated. Differences were assessed with one-way analysis of variance, Fisher exact, and Student t tests.

RESULTS

Differences in SUV(max) between high-grade gliomas (1.89 +/- 0.78 [mean +/- standard deviation]), metastases (4.11 +/- 1.68), and benign lesions (0.59 +/- 0.31) were significant (P < .0001). LNRs also differed significantly (5.15 +/- 2.51, 10.91 +/- 2.14, and 1.28 +/- 0.32, respectively; P < .0001). These differences were also significant at pairwise analysis. The peritumoral LNR exceeded 2.0 in seven high-grade gliomas and no metastases (P = .02). In 14 radiation-treated patients, the lesions classified as benign demonstrated significantly less uptake compared with the recurrent tumors (SUV(max): 0.72 +/- 0.38 vs 2.27 +/- 1.24, P < .01; LNR: 1.36 +/- 0.43 vs 5.88 +/- 3.66, P < .01).

CONCLUSION

High-grade gliomas, metastases, and benign lesions can be distinguished on the basis of measured fluorocholine uptake. Increased peritumoral fluorocholine uptake is a distinguishing characteristic of high-grade gliomas.

Brain tumor imaging and cancer management: the neuro-oncologists perspective

Brain tumors remain a significant cause of morbidity and mortality and are often refractory to treatment. Neuroimaging, in particular magnetic resonance imaging (MRI) and associated techniques, has become an important tool for the neuro-oncologist in the management of brain tumors. Magnetic resonance imaging is the most sensitive method to demonstrate the presence of a mass in the brain and can often narrow the differential diagnosis with nonneoplastic lesions such as cerebral abscess and subacute infarction. Once the diagnosis has been confirmed, MRI is essential for initial treatment planning, including surgical resection and radiation therapy. In selected patients, serial MRI will also be necessary to evaluate for response during adjuvant chemotherapy and to monitor for treatment-induced toxicity. New magnetic resonance techniques such as magnetic resonance spectroscopy, diffusion-weighted imaging, and perfusion-based imaging methods will also be discussed where applicable.

Pitfalls in the diagnosis of brain tumours

Establishing the diagnosis of a brain tumour is not always a straightforward process. Many non-neoplastic neurological diseases can mimic brain neoplasms on neuroimaging or on histological examination, including multiple sclerosis, stroke, pyogenic abscess, toxoplasmosis, tuberculosis, cysticercosis, fungal infections, syphilis, sarcoidosis, Behçet disease, radiation necrosis, venous thrombosis, and others. Conversely, several types of brain neoplasms, such as glioblastomas, low-grade gliomas, CNS lymphomas, and brain metastases, can present in the absence of typical tumefactive lesions, posing significant diagnostic challenges. In this Review, we discuss the process of accurately establishing the diagnosis of brain tumours, focusing on pitfalls commonly encountered in clinical practice. We also discuss the rational use and limitations of new diagnostic techniques, such as diffusion-weighted MRI, perfusion-weighted MRI, magnetic resonance spectroscopy, single-photon emission tomography, and positron emission tomography, as well as new tools for histological examination, such as immunohistochemistry and molecular genetics analysis.