Yamada et al. Journal of Medical Case Reports 2012, 6:104 http://www.jmedicalcasereports.com/content/6/1/104 C A S E R E P O R T JOURNAL OF MEDICAL CASE REPORTS Open Access Tumefactive multiple sclerosis requiring emergent biopsy and histological investigation to confirm the diagnosis: a case report So Yamada1, Shoko Merrit Yamada1*, Hiroshi Nakaguchi1, Mineko Murakami1, Katsumi Hoya1, Akira Matsuno1, Kazuto Yamazaki2 and Yasuo Ishida2 Abstract Introduction: Tumefactive multiple sclerosis is a demyelinating disease that demonstrates tumor-like features on magnetic resonance imaging. Although diagnostic challenges without biopsy have been tried by employing radiological studies and cerebrospinal fluid examinations, histological investigation is still necessary for certain diagnosis in some complicated cases. Case presentation: A 37-year-old Asian man complaining of mild left leg motor weakness visited our clinic. Magnetic resonance imaging demonstrated high-signal lesions in bilateral occipital forceps majors, the left caudate head, and the left semicentral ovale on fluid-attenuated inversion recovery and T2-weighted imaging, and these lesions were enhanced by gadolinium-dimeglumin. Tumefactive multiple sclerosis was suspected because the enhancement indistinctly extended along the corpus callosum on magnetic resonance imaging and scintigraphy showed a low malignancy of the lesions. But oligoclonal bands were not detected in cerebrospinal fluid. In a few days, his symptoms fulminantly deteriorated with mental confusion and left hemiparesis, and steroid pulse therapy was performed. In spite of the treatment, follow-up magnetic resonance imaging showed enlargement of the lesions. Therefore, emergent biopsy was performed and finally led to the diagnosis of demyelinating disease. The enhanced lesion on magnetic resonance imaging disappeared after one month of prednisolone treatment, but mild disorientation and left hemiparesis remained as sequelae. Conclusions: Fulminant aggravation of the disease can cause irreversible neurological deficits. Thus, an early decision to perform a biopsy is necessary for exact diagnosis and appropriate treatment if radiological studies and cerebrospinal fluid examinations cannot rule out the possibility of brain tumors. Introduction Tumefactive multiple sclerosis (tMS) is a demyelinating disease. Because of its tumor-like features on magnetic resonance imaging (MRI) [1,2], histological investigation had played an important role for definite diagnosis of tMS [3,4]. Recently, without biopsy, some tMS cases were diagnosed by magnetic resonance spectroscopy (MRS), positron emission tomography (PET), cerebrosp- inal fluid (CSF) examination, and response to steroid treatment [5-9]. However, the diagnosis of tMS without histological confirmation is no more than speculation in * Correspondence: merrityamada@hotmail.co.jp 1Department of Neurosurgery, Teikyo University Chiba Medical Center, 3426- 3 Anesaki, Ichihara-city, Chiba-prefecture 299-0111, Japan Full list of author information is available at the end of the article some complicated cases. We report the case of a patient who had tMS and who required emergent biopsy for exact diagnosis because of rapid enlargement of lesions on MRI after steroid pulse therapy. Case presentation A 37-year-old Asian man who complained of a two- month history of dizziness visited our clinic. Neurologi- cal examinations using the manual muscle test revealed a left leg motor weakness of 5-/5 on the Medical Research Council (MRC) scale [10,11]. MRI demon- strated high-signal lesions in bilateral occipital forceps majors, the left caudate head, and the left semicentral ovale on both fluid-attenuated inversion recovery (FLAIR) and T2-weighted (T2W) imaging (Figure 1, © 2012 Yamada et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.