Incidental findings in the post-treatment whole body iodine scan (WBIS) sometimes have a broad list of differentials. We present a case of differentiated thyroid carcinoma (DTC), pT3aN1b, with family history of DTC. She was treated with adjuvant 131I therapy (5.55 GBq). The patient's post-treatment WBIS revealed a large, round iodine-avid area above the bladder, which was attributed to a massive uterine fibroid. Physical examination as well as radiologic correlation with SPECT/CT were also concordant. Fibroids can trap the radioiodine by various mechanisms. This case serves as a reminder of an uncommon pitfall in WBIS, particularly in women of reproductive age.
Haugen BR, Alexander EK, Bible KC, Doherty GM, Mandel SJ, Nikiforov YE, Pacini F, Randolph GW, Sawka AM, Schlumberger M, Schuff KG, Sherman SI, Sosa JA, Steward DL, Tuttle RM, Wartofsky L. 2015 American thyroid association management guidelines for adult patients with thyroid nodules and differentiated thyroid cancer: the american thyroid association guidelines task force on thyroid nodules and differentiated thyroid cancer. Thyroid. 2016 Jan;26(1):1-133.
Stewart EA, Cookson CL, Gandolfo RA, Schulze-Rath R. Epidemiology of uterine fibroids: a systematic review. BJOG. 2017 Sep;124(10):1501-12.
Spinos N, Terzis G, Crysanthopoulou A, Adonakis G, Markou KB, Vervita V, Koukouras D, Tsapanos V, Decavalas G, Kourounis G, Georgopoulos NA. Increased frequency of thyroid nodules and breast fibroadenomas in women with uterine fibroids. Thyroid. 2007 Dec;17(12):1257-9.
Braganza MZ, Berrington de González A, Schonfeld SJ, Wentzensen N, Brenner AV, Kitahara CM. Benign breast and gynecologic conditions, reproductive and hormonal factors, and risk of thyroid cancer. Cancer Prev Res (Phila). 2014 Apr;7(4):418-25.
Kim MH, Park YR, Lim DJ, Yoon KH, Kang MI, Cha BY, Lee KW, Son HY. The relationship between thyroid nodules and uterine fibroids. Endocr J. 2010;57(7):615-21.
Sun LM, Chung LM, Lin CL, Kao CH. Uterine Fibroids Increase the Risk of Thyroid Cancer. Int J Environ Res Public Health. 2020 May 28;17(11):3821.
Guenego A, Mesrine S, Dartois L, Leenhardt L, Clavel-Chapelon F, Kvaskoff M, Boutron-Ruault MC, Bonnet F. Relation between hysterectomy, oophorectomy and the risk of incident differentiated thyroid cancer: The E3N cohort. Clin Endocrinol (Oxf). 2019 Feb;90(2):360-8.
Oh JR, Ahn BC. False-positive uptake on radioiodine whole-body scintigraphy: physiologic and pathologic variants unrelated to thyroid cancer. Am J Nucl Med Mol Imaging. 2012;2(3):362-85.
Teo TY, Menda Y, Mcneely P, Kahn D, Graham M. False-positive radioactive iodine uptake in uterine fibroids. Clin Med Rev Case Rep. 2015;2:71.
Almohamad FA, Ahmad T, Ahmad B, Hussain K, Hadid L, Zein M, Ahmad M. False-positive radioiodine accumulation in a huge pelvic mass after thyroidectomy for papillary carcinoma, a case report from Syria. J Surg Case Rep. 2018 Feb 28;2018(2):rjy028.
Benbassat CA, Mechlis-Frish S, Hirsch D. Clinicopathological characteristics and long-term outcome in patients with distant metastases from differentiated thyroid cancer. World J Surg. 2006 Jun;30(6):1088-95.
Jang HY, Kim BH, Kim WJ, Jeon YK, Kim SS, Kim YK, Kim IJ. False-positive radioiodine uptake in a functional ovarian cyst in a patient treated with total thyroidectomy for papillary cancer. Intern Med. 2013 Oct 15;52(20):2321–3.
Lazarus JH, Richards AR, MacPherson MJ, Dinnen JS, Williams ED, Owen GM, Wade JS. Struma ovarii: a case report. Clin Endocrinol (Oxf). 1987 Dec;27(6):715-20.
Emami-Ardekani A, Amini H, Harsini S, Fard-Esfahani A, Eftekhari M. Unusual false-positive results of whole-body 131I scintigraphy: Four different case scenarios. Iran J Nucl Med. 2019;27(2):149-153.
Saber Tanha, A., Rabani, F., Raeisi, N., & Askari, E. (2024). False-positive radioactive iodine uptake in a large uterine fibroid. Iranian Journal of Nuclear Medicine, 32(2), 241-243. doi: 10.22034/irjnm.2024.129529.1602
MLA
Amin Saber Tanha; Faeze Rabani; Nasrin Raeisi; Emran Askari. "False-positive radioactive iodine uptake in a large uterine fibroid". Iranian Journal of Nuclear Medicine, 32, 2, 2024, 241-243. doi: 10.22034/irjnm.2024.129529.1602
HARVARD
Saber Tanha, A., Rabani, F., Raeisi, N., Askari, E. (2024). 'False-positive radioactive iodine uptake in a large uterine fibroid', Iranian Journal of Nuclear Medicine, 32(2), pp. 241-243. doi: 10.22034/irjnm.2024.129529.1602
VANCOUVER
Saber Tanha, A., Rabani, F., Raeisi, N., Askari, E. False-positive radioactive iodine uptake in a large uterine fibroid. Iranian Journal of Nuclear Medicine, 2024; 32(2): 241-243. doi: 10.22034/irjnm.2024.129529.1602