Non-neoplastic demyelinating process mimicking a disseminated malignant brain tumour

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.

Evolution and long term outcome in patients presenting with large demyelinating lesions as their first clinical event

OBJECTIVES

To describe the long term evolution and outcome of a homogeneous cohort of patients (n=14) with large demyelinating lesions (LDLs) as the first clinical event from a group of idiopathic inflammatory demyelinating diseases of central nervous system.

METHODS

Detailed review of LDLs from December 2002-January 2007 was made. Patients had at least two magnetic resonance imaging (MRI) and minimum follow-up of 2years. The disability was assessed using Estimated Expanded Disability Status Scale (EDSS) and Rappaport Disability Rating Scale (DRS) at onset and last follow-up.

RESULTS

Fourteen consecutive LDL patients (male=7), with mean age 32.7years and mean follow-up of 45.5months were included. Motor deficits (79%) and cognitive symptoms (43%) marked the onset, none had optic neuritis. All except two responded to steroids. Follow-up MRI showed complete resolution in 43%, 57% showing marked reduction in size. On follow-up, 2 relapsed. Mean EDSS and DRS at presentation were 5.93 and 9.07 and at last follow-up were 1.75 and 2.25 (p<0.001).

CONCLUSIONS

Our data suggests that, patients presenting with LDLs as their first clinical event behaves distinctly in their presentation, imaging characteristics, prognosis and long term outcome as compared to MS and ADEM. Albeit significant disability at the onset, these patients show an excellent response to treatment with good functional recovery in long term and rare relapses.

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.

Astrocytoma-like multiple sclerosis

Multiple sclerosis (MS) may sometimes mimic clinically and radiologically a brain tumor. The initial recognition of such cases is essential as it might avoid a surgical intervention and supplementary treatment. However, even in patients who underwent surgery, the appropriate preparation of the specimen is of crucial importance for the correct pathological diagnosis since tumors and non-neoplastic demyelinating lesions share some common histopathological features. We present such a case of multiple sclerosis presenting with features of an astrocytoma and was treated with surgery and additional radiotherapy.