Pheochromocytoma in Multiple Endocrine Neoplasia Type 2A Positive 123 I MIBG With Negative CT and Equivocal 131 I MIBG Imaging Shirou Ishii, MD, Fumio Shishido, MD, Masayuki Miyajima, MD, Kotaro Sakuma, MD, andKen Kikuchi, MD Abstract: An 123 I metaiodobenzylguanidine (MIBG) planar image showed abnormal uptake in the left adrenal gland and thyroid in a 24-year-old woman with multiple endocrine neoplasia type 2A. 131 I MIBG showed abnormal uptake in the thyroid but not in the adrenal gland. Abdominal CT with 2-mm thin slices demonstrated a normal adrenal gland. Postoperative pathologic findings were consistent with medullary carcinoma in both thyroid lobes and a small 1-mm pheochromocytoma in the left adrenal gland. 123 I MIBG could clearly show the small pheochromocytoma, which was negative in thin-slice CT and equivocal in 131 I MIBG. Key Words: pheochromocytoma, MIBG, multiple endocrine neoplasia, medullary thyroid carcinoma (Clin Nucl Med 2012;37: 596Y598) REFERENCES 1. Rufini V, Calcagni ML, Baum RP. Imaging of neuroendocrine tumors. Semin Nucl Med. 2006;36:228Y247. 2. Lumachi F, Tregnaghi A, Zucchetta P, et al. Sensitivity and positive predictive value of CT, MRI and 123I-MIBG scintigraphy in localizing pheochromocy- tomas: a prospective study. Nucl Med Commun. 2006;27:583Y587. 3. Berglund AS, Hulthen UL, Manhem P, et al. Metaiodobenzylguanidine (MIBG) scintigraphy and computed tomography (CT) in clinical practice. Primary and secondary evaluation for localization of pheochromocytomas. J Intern Med. 2001;49:247Y251. 4. Jacobson AF, Deng H, Lombard J, et al. 123I-meta-iodobenzylguanidine scintigraphy for the detection of neuroblastoma and pheochromocytoma: results of a meta-analysis. J Clin Endocrinol Metab. 2010;95:2596Y2606. 5. Lenders JW, Eisenhofer G, Mannelli M, et al. Phaeochromocytoma. Lancet. 2005;36:665Y675. 6. Rodriguez JM, Balsalobre M, Ponce JL, et al. Pheochromocytoma in MEN 2A syndrome. Study of 54 patients. World J Surg. 2008;32:2520Y2526. 7. Shulkin BL, Shapiro B, Francis IR, et al. Primary extra-adrenal pheochromo- cytoma: positive 123 I MIBG imaging with negative 131 I MIBG imaging. Clin Nucl Med. 1986;11:851Y854. 8. Mozley PD, Kim CK, Mohsin J, et al. The efficacy of iodine-123-MIBG as a screening test for pheochromocytoma. J Nucl Med. 1994;35:1138Y1144. 9. Fukuoka M, Taki J, Mochizuki T, et al. Comparison of diagnostic value of 123 I MIBG and high-dose 131 I MIBG scintigraphy including incremental value of SPECT/CT over planar image in patients with malignant pheochromocytoma/ paraganglioma and neuroblastoma. Clin Nucl Med. 2011;36:1Y7. INTERESTING IMAGE 596 www.nuclearmed.com Clinical Nuclear Medicine & Volume 37, Number 6, June 2012 Received for publication November 4, 2011; revision accepted December 29, 2011. From the Department of Radiology, Fukushima Medical University, Hikarigaoka, Fukushima, Japan. Conflicts of interest and sources of funding: none declared. Reprints: Shirou Ishii, MD, Department of Radiology, Fukushima Medical Uni- versity Hospital, 1 Hikarigaoka, Fukushima, Japan. E-mail: shirou@fmu.ac.jp. Copyright * 2012 by Lippincott Williams & Wilkins ISSN: 0363-9762/12/3706-0596 Copyright © 2012 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.