18 F-FDG PET/CT of Brown Adipose Tissue Hyperactivation Associated With Pregnancy and Paraganglioma Anna Margherita Maffione, MD,* Lucia Rampin, MD,* Sotirios Chondrogiannis, MD,* Maria Cristina Marzola, MD,* Patrick M. Colletti, MD,† and Domenico Rubello, MD* Abstract: This 32-year-old woman presented with pregnancy-related arte- rial hypertension unresponsive to antihypertensive therapy. During cesarean delivery, a lobulated retroperitoneal mass was discovered. 18 F-FDG PET/CT performed 18 days postpartum demonstrated the hyperactive retroperitoneal mass and extensive hyperactivated brown adipose tissue. The mass was sur- gically removed, revealing a para-aortic multicentric paraganglioma. After surgery, blood pressure normalized, and serum chromogranin A and urinary metanephrines normalized. Brown adipose tissue hypermetabolism disap- peared on follow-up FDG PET. Her initial FDG PET demonstrated brown adipose tissue hyperactivation, which may have been caused by the combi- nation of hormonal changes in pregnancy and the paraganglioma. Key Words: 18 F-FDG, arterial hypertension, blood pressure, brown adipose tissue (BAT), metanephrine, paraganglioma, PET/CT, pregnancy (Clin Nucl Med 2017;00: 00–00) REFERENCES 1. Alkhawaldeh K, Alavi A. Quantitative assessment of FDG uptake in brown fat using standardized uptake value and dual-time-point scanning. Clin Nucl Med. 2008;33:663–667. 2. Clarke JR, Brglevska S, Lau EW, et al. Atypical brown fat distribution in young males demonstrated on PET/CT. Clin Nucl Med. 2007;32:679–682. 3. Minotti AJ, Shah L, Keller K. Positron emission tomography/computed tomography fusion imaging in brown adipose tissue. Clin Nucl Med. 2004;29:5–11. 4. Cheng W, Zhu Z, Jin X, et al. Intense FDG activity in the brown adipose tissue in omental and mesenteric regions in a patient with malignant pheochromocy- toma. Clin Nucl Med. 2012;37:514–515. 5. Champigny O, Hitier Y. Lipoprotein lipase activity in skeletal muscle and brown adipose tissue of pregnant and lactating rats. J Nutr. 1987;117:349–354. 6. Dong A, Wang Y, Lu J, et al. Hypermetabolic mesenteric brown adipose tissue on dual-time point FDG PET/CT in a patient with benign retroperitoneal pheochromocytoma. Clin Nucl Med. 2014;39:e229–e232. 7. Joshi PV, Lele VR. Unexpected visitor on FDG PET/CT—brown adipose tis- sue (BAT) in mesentery in a case of retroperitoneal extra-adrenal pheochro- mocytoma: is the BAT activation secondary to catecholamine-secreting pheochromocytoma? Clin Nucl Med. 2012;37:e119–e120. 8. Banzo J, Ubieto MA, Berisa MF, et al. Extensive hypermetabolic pattern of brown adipose tissue activation on 18 F-FDG PET/CT in a patient diagnosed of catecholamine-secreting para-vesical paraganglioma. Rev Esp Med Nucl Imagen Mol. 2013;32:397–399. 9. Puar T, van Berkel A, Gotthardt M, et al. Genotype-dependent brown adipose tissue activation in patients with pheochromocytoma and paraganglioma. J Clin Endocrinol Metab. 2016;101:224–232. Received for publication July 17, 2017; revision accepted July 25, 2017. From the *Nuclear Medicine and PET Department, Santa Maria della Misericordia Hospital, Rovigo, Italy; and † Department of Radiology, University of Southern California, Los Angeles, CA. Conflicts of interest and sources of funding: none declared. Correspondence to: Anna Margherita Maffione, MD, Department of Nuclear Medicine, Santa Maria della Misericordia Hospital, Viale Tre Martiri, 140, 45100 Rovigo, Italy. E-mail: maffionemarghe@libero.it. Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0363-9762/17/0000–0000 DOI: 10.1097/RLU.0000000000001819 INTERESTING IMAGE Clinical Nuclear Medicine • Volume 00, Number 00, Month 2017 www.nuclearmed.com 1 Copyright © 2017 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. This paper can be cited using the date of access and the unique DOI number which can be found in the footnotes.