Int J Thyroidol.  2016 Nov;9(2):180-184. 10.11106/ijt.2016.9.2.180.

Incidental Detection of Struma Ovarii on the Whole Body Scan in a Differentiated Thyroid Cancer Patient

• Oh HS
• Song E
• Song DE
• Kim WB

• KMID: 2362355
• DOI: http://doi.org/10.11106/ijt.2016.9.2.180

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.

Keyword

Differentiated thyroid cancer; Iodine uptake; Teratoma; Struma ovarii

MeSH Terms

Aged
Diagnosis, Differential
Female
Humans
Hydronephrosis
Hysterectomy
Iodine
Nephrectomy
Ovariectomy
Ovary
Struma Ovarii*
Teratoma
Thyroid Gland*
Thyroid Neoplasms*
Thyroidectomy
Tomography, Emission-Computed, Single-Photon
Ureter
Ureteral Neoplasms
Whole Body Imaging*
Iodine

Figure

• 

  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 x200). (D) Large well-demarcated ovoid mass (5.5x4.2x3.7 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 x200). (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 x400).

• 

  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 x40). (E) Focal adenomatous hyperplasia was identified in the areas of struma ovarii (H&E staining, magnification x200).

Reference

References

1. Haugen BR, Alexander EK, Bible KC, Doherty GM, Mandel SJ, Nikiforov YE, et al. 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; 26(1):1–133.

2. Yi KH, Park YJ, Koong SS, Kim JH, Na DG, Ryu JS, et al. Revised Korean Thyroid Association management guidelines for patients with thyroid nodules and thyroid cancer. Endocrinol Metab. 2010; 25(4):270–97.

3. Luster M, Clarke SE, Dietlein M, Lassmann M, Lind P, Oyen WJ, et al. Guidelines for radioiodine therapy of differentiated thyroid cancer. Eur J Nucl Med Mol Imaging. 2008; 35(10):1941–59.

4. 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.

5. Carlisle MR, Lu C, McDougall IR. The interpretation of 131I scans in the evaluation of thyroid cancer, with an emphasis on false positive findings. Nucl Med Commun. 2003; 24(6):715–35.

6. Yu XM, Schneider DF, Leverson G, Chen H, Sippel RS. Follicular variant of papillary thyroid carcinoma is a unique clinical entity: a population-based study of 10,740 cases. Thyroid. 2013; 23(10):1263–8.

7. Englum BR, Pura J, Reed SD, Roman SA, Sosa JA, Scheri RP. A bedside risk calculator to preoperatively distinguish follicular thyroid carcinoma from follicular variant of papillary thyroid carcinoma. World J Surg. 2015; 39(12):2928–34.

8. Bae JS, Choi SK, Jeon S, Kim Y, Lee S, Lee YS, et al. Impact of NRAS mutations on the diagnosis of follicular neoplasm of the thyroid. Int J Endocrinol. 2014; 2014:289834.

9. Filetti S, Bidart JM, Arturi F, Caillou B, Russo D, Schlumberger M. Sodium/iodide symporter: a key transport system in thyroid cancer cell metabolism. Eur J Endocrinol. 1999; 141(5):443–57.

10. Jeong SY, Lee J. Nuclear imaging of differentiated thyroid cancer: current status and future perspective. J Korean Thyroid Assoc. 2011; 4(1):8–17.

11. Hassan FU, Mohan HK. Clinical utility of SPECT/CT imaging post-radioiodine therapy: does it enhance patient management in thyroid cancer? Eur Thyroid J. 2015; 4(4):239–45.

12. Lao M, Koike J, Chauhan S, Schiano M, Plata M. Struma ovarii with a focus of follicular variant of papillary thyroid cancer: a case report. W V Med J. 2008; 104(4):12–4.

13. Chiofalo MG, Misso C, Insabato L, Lastoria S, Pezzullo L. Hyperthyroidism due to coexistence of Graves' disease and struma ovarii. Endocr Pract. 2007; 13(3):274–6.

14. Jammah AA, Driedger A, Rachinsky I. Incidental finding of ovarian teratoma on posttherapy scan for papillary thyroid cancer and impact of SPECT/CT imaging. Arq Bras Endocrinol Metabol. 2011; 55(7):490–3.

15. van Wijk JP, Broekhuizen-de Gast HS, Smits AJ, Schipper ME, Zelissen PM. Scintigraphic detection of benign ovarian teratoma after total thyroidectomy and radioactive iodine for differentiated thyroid cancer. J Clin Endocrinol Metab. 2012; 97(4):1094–5.

16. Yazici B, Oral A, Omur O, Yazici A. Radioiodine uptake in an ovarian mature teratoma detected with SPECT/CT. Clin Nucl Med. 2015; 40(2):e157–60.