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.