Astrocytoma-like multiple sclerosis

Increased Radiosurgery Toxicity Associated With Treatment of Vestibular Schwannoma in Multiple Sclerosis

OBJECTIVE

Explore the risk of radiation-induced neurotoxicity in patients with multiple sclerosis (MS) treated with stereotactic radiosurgery (SRS) and better understand the pathophysiology of radiation-induced injury in the central nervous system (CNS).

PATIENTS/INTERVENTION

We present the clinical course and magnetic resonance imaging (MRI) findings of a 52-year-old woman with a history of relapsing remitting MS, who developed radiation-induced neurotoxicity following CyberKnife SRS (25 Gy in five fractions) for a left-sided vestibular schwannoma (VS).

MAIN OUTCOME MEASURE

Risk of radiation-induced damage following SRS to the CNS, including radiation type and dose, toxicity, and time to symptom onset, in patients with MS.

RESULTS

Our patient developed increased imbalance (grade 2 toxicity) 3 months following CyberKnife SRS. Brain MRI showed new fluid-attenuated inversion recovery (FLAIR) hyperintensity in the pons and cerebellum. Neurotoxicity from SRS is rare. However, our literature review showed that 19 patients with MS who underwent intracranial radiation therapy sustained radiation-induced toxicity. The potential mechanisms for increased toxicity in MS could be due to a combination of demyelination, inflammatory, and/or vascular changes. Efficacy of treatments including steroids, bevacizumab, and hyperbaric oxygen therapy is currently unknown.

CONCLUSION

Treatment options of SRS and surgery for VS should be carefully considered as patients with known MS may be at increased risk for radiation-induced damage following SRS to the CNS. Thoughtful radiosurgical planning and dosing accounting for this inherent risk is essential for managing patients with MS and VS.

Machine learning-based differentiation between multiple sclerosis and glioma WHO II°-IV° using O-(2-[18F] fluoroethyl)-L-tyrosine positron emission tomography

INTRODUCTION

This study aimed to test the diagnostic significance of FET-PET imaging combined with machine learning for the differentiation between multiple sclerosis (MS) and glioma II°-IV°.

METHODS

Our database was screened for patients in whom FET-PET imaging was performed for the diagnostic workup of newly diagnosed lesions evident on MRI and suggestive of glioma. Among those, we identified patients with histologically confirmed glioma II°-IV°, and those who later turned out to have MS. For each group, tumor-to-brain ratio (TBR) derived features of FET were determined. A support vector machine (SVM) based machine learning algorithm was constructed to enhance classification ability, and Receiver Operating Characteristic (ROC) analysis with area under the curve (AUC) metric served to ascertain model performance.

RESULTS

A total of 41 patients met selection criteria, including seven patients with MS and 34 patients with glioma. TBR values were significantly higher in the glioma group (TBRmax glioma vs. MS: p = 0.002; TBRmean glioma vs. MS: p = 0.014). In a subgroup analysis, TBR values significantly differentiated between MS and glioblastoma (TBRmax glioblastoma vs. MS: p = 0.0003, TBRmean glioblastoma vs. MS: p = 0.0003) and between MS and oligodendroglioma (ODG) (TBRmax ODG vs. MS: p = 0.003; TBRmean ODG vs. MS: p = 0.01). The ability to differentiate between MS and glioma II°-IV° increased from 0.79 using standard TBR analysis to 0.94 using a SVM based machine learning algorithm.

CONCLUSIONS

FET-PET imaging may help differentiate MS from glioma II°-IV° and SVM based machine learning approaches can enhance classification performance.

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.

Diffuse glioblastoma resembling acute hemorrhagic leukoencephalitis

We report the case of a young man with sudden onset of diplopia after an upper respiratory tract infection. Based on the first radiological findings acute hemorrhagic leukoencephalitis, a variant of acute disseminated encephalomyelitis, was suspected and treatment with high dose intravenous dexamethasone was started but it was stopped for intolerance. The patient clinically worsened, developing gait instability, ataxia and ophthalmoplegia; brain MRI performed 20 days later showed severe progression of the disease with subependymal dissemination. After brain biopsy of the right temporal lesion the histological diagnosis was glioblastoma. These findings suggest that MRI features of acute hemorrhagic leukoencephalitis may dissimulate the diagnosis of diffuse glioma/glioblastoma. This case underscores the importance of considering diffuse glioma in the differential diagnosis of atypical signs and symptoms of acute hemorrhagic leukoencephalitis and underlines the relevant role of integrating neuroradiologic findings with neuropathology.

Tumefactive demyelination: clinical, imaging and follow-up observations in thirty-nine patients

PURPOSE

We describe the clinical, neuroimaging and pathological features and therapeutic outcome in a large cohort of 39 patients with tumefactive demyelination.

MATERIALS AND METHODS

A retrospective audit of 39 patients with 'tumefactive demyelination' was performed. The demographic, clinical, MR imaging and pathological details were reviewed.

RESULTS

The clinical course was monophasic (n = 22) or relapsing-remitting (n = 17). Common neurological manifestations at presentation included hemiparesis - 27; ataxia - 11; vomiting - 10; headache -9; ophthalmoplegia - 7; seizure - 5; impaired vision - 4; aphasia - 4; visual field defects - 3; papilloedema - 5; extrapyramidal - 5; intellectual decline - 5; behavioural disturbances - 3; altered sensorium - 5. MRI revealed fronto-parietal lesions, which were isolated in 14 (36%) patients. Moderate perilesional oedema and/or mass effect was noted in 12 (30.8%) patients. Post-contrast MR sequences revealed partial ring enhancement in 15, complete ring in seven, patchy enhancement in six, uniform enhancement in two and lack of enhancement in nine cases. Clinical and MR characteristics did not help distinguish between monophasic and relapsing-remitting subgroups. In the monophasic group, 53.8% had complete recovery, while 38.5% had partial improvement (follow-up duration, 8.31 ± 9.3 months). In the relapsing-remitting subgroup, the median time to relapse was 4 months (n = 12, follow-up, 37.8 ± 39.4 months). Patients with monophasic course or single relapse received steroids. Patients with more than one relapse received cyclophosphamide (2), mycophenolate (1), azathioprine (1) or methotrexate (1).

CONCLUSIONS

A high proportion of cases of tumefactive demyelination follow a relapsing course, thus necessitating a long-term follow-up. MRI, although helpful in diagnosis, does not predict monophasic or relapsing-remitting course. Guidelines for the management of acute episodes and prevention of relapses are required.

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.

A 45-year old male with left-sided hemihypesthesia

A 45-year-old man presented with progressive brainstem and cerebellar dysfunction. Extensive immunological and radiological investigations were not able to differentiate between an intrinsic brain tumor and a demyelinating disease. Stereotactic biopsies of the brainstem were performed; the findings of abundant Rosenthal fibers, interjacent spindle-shaped and gemistocytic cells partially with dark and irregularly formed nuclei favored primarily the diagnosis of a malignant astrocytoma, although a demyelinating disease could not be definitely excluded. Facing the fulminant clinical course radio- and chemotherapy was initiated; however, the patient died of sepsis-associated multi-organ failure three and a half years after disease onset. Post mortem pathology finally revealed lesions with central amorphic necrosis surrounded by areas of significant demyelination, astrocytosis, microglia cells and macrophages typical for MS. Although criteria for establishing MS are well known, a correct diagnosis can be extremely challenging in small stereotactic specimens, where so-called pathological hallmarks are spared and unusual pathological findings are predominant.

Radiation-induced optic neuritis after pituitary adenoma radiosurgery in a patient with multiple sclerosis: case report

OBJECTIVE AND IMPORTANCE

To describe a rare case of optic neuritis onset after Gamma Knife stereotactic radiosurgery.

CLINICAL PRESENTATION

Nine years after transsphenoidal subtotal resection of a pituitary adenoma, this 43-year-old woman had elevated serum prolactin levels and headaches.

INTERVENTION

Gamma Knife stereotactic radiosurgery to residual pituitary tumor.

CONCLUSION

To our knowledge, this is the first report of radiation-induced optic neuritis after radiosurgery in a patient with multiple sclerosis.

Intracranial lesions mimicking neoplasms

CONTEXT

A broad spectrum of nonneoplastic conditions can mimic a brain tumor, both clinically and radiologically. In this review we consider these, taking into consideration the following etiologic categories: infection, demyelination, vascular diseases, noninfectious inflammatory disorders, and iatrogenic conditions. We give an overview of such diseases, which represent a potential pitfall for pathologists and other clinicians involved in patient care, and present selected cases from each category.

OBJECTIVE

To illustrate the radiologic and pathologic features of nontumoral intracranial lesions that can clinically and radiologically mimic neoplasia.

DATA SOURCES

Case-derived material and literature review.

CONCLUSIONS

A variety of nonneoplastic lesions can present clinically and radiologically as primary or metastatic central nervous system tumors and result in surgical biopsy or resection of the lesion. In such situations, the pathologist has an important role to play in correctly determining the nature of these lesions. Awareness of the entities that can present in this way will assist the pathologist in the correct diagnosis of these lesions.

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.

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.

Multiple sclerosis, brain radiotherapy, and risk of neurotoxicity: the Mayo Clinic experience

PURPOSE

The aim of this study was a retrospective assessment of neurotoxicity in patients with multiple sclerosis (MS) receiving external beam radiotherapy (EBRT) to the brain.

METHODS AND MATERIALS

We studied 15 consecutively treated patients with MS who received brain EBRT. Neurologic toxicity was assessed with the Common Toxicity Criteria v.3.0.

RESULTS

Median follow-up for the 5 living patients was 6.0 years (range, 3.3-27.4 years). No exacerbation of MS occurred in any patient during EBRT. Five patients had Grade 4 neurologic toxicity and 1 had possible Grade 5 toxicity. Kaplan-Meier estimated risk of neurotoxicity greater than Grade 4 at 5 years was 57% (95% confidence interval, 27%-82%). Toxicity occurred at 37.5 to 54.0 Gy at a median of 1.0 year (range, 0.2-4.3 years) after EBRT. Univariate analysis showed an association between opposed-field irradiation of the temporal lobes, central white matter, and brainstem and increased risk of neurotoxicity (p < 0.04). Three of 6 cases of toxicity occurred in patients treated before 1986.

CONCLUSIONS

External beam radiotherapy of the brain in patients with MS may be associated with an increased risk of neurotoxicity compared with patients without demyelinating illnesses. However, this risk is associated with treatment techniques that may not be comparable to modern, conformal radiotherapy.