A Tumefactive Multiple Sclerosis Lesion in the Brain: An Uncommon Site with Atypical Magnetic Resonance Image Findings

Tumefactive multiple sclerosis (MS) is an uncommon manifestation of multiple sclerosis (1). The characteristic MRI findings for this demyelinating disease are a large isolated mass in the white matter with incomplete rim enhancement, slight perilesional edema and a mass effect (2, 3). The clinical features of tumefactive MS are variable and polysymptomatic, depending on the location and size of the mass (4). Patients with this lesion commonly present with headache, cognitive abnormalities, and sub-acute progressive motor and/or sensory symptoms (5). Most patients with this type of MS manifest only a single acute clinical presentation, whereas those with typical MS present with recurrent episodes of neurological symptoms (4, 6). For these reasons tumefactive MS is indistinguishable from glial neoplasm, lymphoma, abscess or other similar types of lesions (2). Thus, awareness of the characteristic MRI appearance of these lesions can be helpful for correctly diagnosing this condition in a noninvasive manner (6). We report herein a case of pathologically confirmed tumefactive MS in an uncommon location, which showed atypical magnetic resonance (MR) imaging findings and a good response to steroid therapy. We also summarize the typical MR imaging findings for tumefactive MS that can be used to differentiate this lesion from others.