18 F-FDG PET/CT in Tumefactive Multiple Sclerosis Anna Margherita Maffione, MD,* Lucia Rampin, MD,* Gaia Grassetto, MD,* Roberto L’Erario, MD,Þ Patrick M Colletti, MD,þ and Domenico Rubello, MD* Abstract: A 35-year-old man underwent contrast-enhanced MRI and 18 F- FDG PET/CT for acute peripheral paresthesia, vision loss, muscle weakness, and difficulty walking. T2-weighted MRI demonstrated multiple bright periventricular supratentorial and infratentorial white matter lesions, includ- ing 2 with nodularity. Both nodular lesions showed moderate focal FDG up- take (SUV max , 6.9 in both cases). Cerebrospinal fluid analysis showed increased levels of immunocytes and oligoclonal antibody bands. A diagno- sis of acute onset tumefactive multiple sclerosis was made. Key Words: PET, multiple sclerosis, MRI, FDG, active plaque (Clin Nucl Med 2014;39: 750Y751) REFERENCES 1. Lakhanpal SK, Maravilla JR. Multiple sclerosis. In: Stark DD, Bradley WG, eds. Magnetic Resonance Imaging. 3rd ed. St Louis, MO: Mosby; 1999. 2. Altintas A, Petek B, Isik N, et al. Clinical and radiological characteristics of tumefactive demyelinating lesions: follow-up study. Mult Scler . 2012;18: 1448Y1453. 3. Chen W, Silverman DH, Delaloye S, et al. 18 F-FDOPA PET imaging of brain tumors: comparison study with 18 F-FDG PET and evaluation of diagnostic ac- curacy. J Nucl Med. 2006;47:904Y911. 4. Gay FW, Drye TJ, Dick GW, et al. The application of multifactorial cluster analysis in the staging of plaques in early multiple sclerosis. Identification and characterization of the primary demyelinating lesion. Brain. 1997;120(Pt 8): 1461Y1483. 5. Adams CW, Poston RN, Buk SJ. Pathology, histochemistry and immunocyto- chemistry of lesions in acute multiple sclerosis. J Neurol Sci. 1989;92:291Y306. 6. Niccolini F, Su P, Politis M. Positron emission tomography in multiple sclerosis. Clin Nucl Med. 2014. [Epub ahead of print]. 7. Kiferle L, Politis M, Muraro PA, et al. Positron emission tomography imaging in multiple sclerosis-current status and future applications. Eur J Neurol. 2011;18: 226Y231. 8. Bakshi R, Miletich RS, Kinkel PR, et al. High-resolution fluorodeoxyglucose positron emission tomography shows both global and regional cerebral hypo- metabolism in multiple sclerosis. J Neuro Imag. 1998;8:228Y234. INTERESTING IMAGE 750 www.nuclearmed.com Clinical Nuclear Medicine & Volume 39, Number 8, August 2014 Received for publication January 15, 2014; revision accepted February 12, 2014. From the Departments of *Nuclear Medicine, PET Unit, and †Neurology, Santa Maria della Misericordia Hospital, Rovigo, Italy; and ‡Department of Radiol- ogy, University of Southern California, Los Angeles, CA. Conflicts of interest and sources of funding: none declared. Reprints: Domenico Rubello, MD, Department of Nuclear Medicine, Santa Maria della Misericordia Hospital, Rovigo, Italy, Viale Tre Martiri, 140, 45100 Rovigo, Italy. E-mail: domenico.rubello@libero.it. Copyright * 2014 by Lippincott Williams & Wilkins ISSN: 0363-9762/14/3908Y0750 Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.