Journal List > Int J Thyroidol > v.9(2) > 1082743

Int J Thyroidol. 2016 Nov;9(2):180-184. Korean.
Published online November 30, 2016.  https://doi.org/10.11106/ijt.2016.9.2.180
Copyright © 2016. the Korean Thyroid Association. All rights reserved.
Incidental Detection of Struma Ovarii on the Whole Body Scan in a Differentiated Thyroid Cancer Patient
Hye-Seon Oh,1 Eyun Song,1 Dong Eun Song,2 and Won Bae Kim1
1Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
2Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Correspondence: Won Bae Kim, MD, PhD, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea. Tel: 82-2-3010-3913, Fax: 82-2-3010-6962, Email: kimwb@amc.seoul.kr
Received April 19, 2016; Revised June 14, 2016; Accepted June 20, 2016.

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


Abstract

Post-therapeutic whole body scan (RxWBS) after radioactive iodine (RAI) remnant ablation (RRA) is useful for detect recurrent or metastatic foci of differentiated thyroid carcinoma (DTC) after total thyroidectomy. However, there is rare possibility of false positive iodine uptake in WBS. Here, we report a case of a 72-year-old woman, who underwent RRA after total thyroidectomy due to follicular variant papillary thyroid carcinoma. There is an abnormal iodine uptake in RxWBS in pelvic cavity. Additional single photon emission computed tomography (SPECT)-computed tomography (CT) imaging showed an intensive I-131 avid mass in left ovary. There was a multiple calcified mass in left ovary and enhancing wall thickening in left ureter with hydronephrosis in contrast enhanced CT. She underwent hysterectomy, oophorectomy, left ureterectomy and nephrectomy and diagnosed as mature cystic teratoma with thyroid tissues and ureter cancer. Struma ovarii should be considered if there was abnormal RAI uptake in pelvic cavity. I-131 SPECT-CT is useful for differential diagnosis of abnormal iodine uptakes in WBS.

Keywords: Differentiated thyroid cancer; Iodine uptake; Teratoma; Struma ovarii

Figures


Fig. 1
Representative radiologic and pathologic images of the thyroid cancer. Thyroid ultrasonograhy (US) images (A, B) thyroid US reveals 5.5-cm-sized hypoechoic nodule with smooth margin at the lower pole of right thyroid lobe (A) and another isoechoic 0.7-cm-sized nodule with irregular margin at the mid pole of left thyroid lobe (B). (C) Core needle biopsy for the right thyroid nodule revealed histological features of suspicious for follicular neoplasm with thin tumor capsule and microfollicular proliferation (H&E staining, magnification ×200). (D) Large well-demarcated ovoid mass (5.5×4.2×3.7 cm) on lower pole of right lobe and several ovoid nodules were in surgical specimen after total thyroidectomy showed. (E) Tumor on right lobe revealed encapsulated invasive follicular variant of papillary carcinoma (FV-PTC) with capsular invasion (H&E staining, magnification ×200). (F) Tumor cells of encapsulate invasive FV-PTC revealed mild nuclear atypia including enlarged nuclei, pale chromatin, irregular nuclear membrane and oval nuclear shape, supporting the diagnosis of FV-PTC (H&E staining, magnification ×400).
Click for larger image


Fig. 2
Representative radiologic and pathologic images of the mature cystic teratoma. (A) Posttherapeutic whole body scan at 7 days after the administration 2.96 GBq I-131 showed multifocal thyroid bed uptake due to remnants of normal thyroid and intensive uptake on pelvic area. (B) Additional single photon emission computed tomography (SPECT)-computed tomography (CT) image at 21 days after I-131 remnant ablation showed 8.5-cm-sized intensive radioiodine-avid mass in left ovary or uterine fundus. (C) Abdominopelvic CT showed multiple calcified mass (hollow arrow) with contrast enhancement in left ovary and enhancing wall thickening in left distal ureter (read arrow) with hydronephrosis (arrowhead). (D) Mature cystic teratoma was found on left ovary with struma ovarii component composed of hyperplastic thyroid follicles (H&E staining, magnification ×40). (E) Focal adenomatous hyperplasia was identified in the areas of struma ovarii (H&E staining, magnification ×200).
Click for larger image

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