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Abstract
Background and Objectives
To classify the metastases to the thyroid gland arising from non-thyroidal malignancies on ultrasound (US).
Materials and Methods
We enrolled 45 consecutive patients with metastases to the thyroid gland from 2005 to 2012. We classified metastases into 4 types; type I: diffuse non-mass forming lesion, type II: a solitary suspicious nodule, type III: multiple suspicious nodules, and type IV: nodule(s) with no suspicion. We subcategorized type I into two subtypes; type IA: diffusely infiltrative lesion, type IB: diffuse micronodulation.
Results
The most frequent primary malignancy of thyroid metastases was lung cancer. The patients with thyroid metastases were 26 (57.8%) in type I; type IA: 16 (35.6%), type IB: 10 (22.2%), 14 (31.1%) in type II, 3 (6.7%) in type III and 2 (4.4%) in type IV. Type I metastasis included 18 of 25 patients with lung cancer and all 3 patients with stomach cancer. Thirty patients (73.3%) having type IA, II or III revealed malignant findings on US, in contrast, 12 (26.7%) patients having type IB or IV revealed no suspicious findings.
Conclusion
Type I (diffuse non-mass forming lesion) was the most common in thyroid metastases. A quarter of thyroid metastases revealed no suspicious findings on US. Thyroid metastases can be considered as a differential diagnosis, when diffuse non-mass forming lesions or nodules with no suspicion are revealed on thyroid US.
References
1. Kim TY, Kim WB, Gong G, Hong SJ, Shong YK. Metastasis to the thyroid diagnosed by fine-needle aspiration biopsy. Clin Endocrinol (Oxf). 2005; 62(2):236–41.
2. Chung AY, Tran TB, Brumund KT, Weisman RA, Bouvet M. Metastases to the thyroid: a review of the literature from the last decade. Thyroid. 2012; 22(3):258–68.
3. Chen H, Nicol TL, Udelsman R. Clinically significant, isolated metastatic disease to the thyroid gland. World J Surg. 1999; 23(2):177–80. discussion 181.
4. Czech JM, Lichtor TR, Carney JA, van Heerden JA. Neoplasms metastatic to the thyroid gland. Surg Gynecol Obstet. 1982; 155(4):503–5.
5. Chung SY, Kim EK, Kim JH, Oh KK, Kim DJ, Lee YH. et al. Sonographic findings of metastatic disease to the thyroid. Yonsei Med J. 2001; 42(4):411–7.
6. Calzolari F, Sartori PV, Talarico C, Parmeggiani D, Beretta E, Pezzullo L. et al. Surgical treatment of intrathyroid metastases: preliminary results of a multicentric study. Anticancer Res. 2008; 28(5B):2885–8.
7. Cichon S, Anielski R, Konturek A, Barczynski M, Cichon W. Metastases to the thyroid gland: seventeen cases operated on in a single clinical center. Langenbecks Arch Surg. 2006; 391(6):81–7.
8. Takashima S, Takayama F, Wang JC, Saito A, Kawakami S, Kobayashi S. et al. Radiologic assessment of metastases to the thyroid gland. J Comput Assist Tomogr. 2000; 24(4):539–45.
9. Moon WJ, Baek JH, Jung SL, Kim DW, Kim EK, Kim JY. et al. Ultrasonography and the ultrasound-based management of thyroid nodules: consensus statement and recommendations. Korean J Radiol. 2011; 12(1):1–14.
10. Abrams HL, Spiro R, Goldstein N. Metastases in carcinoma; analysis of 1000 autopsied cases. Cancer. 1950; 3(1):74–85.
11. Mortensen J, Woolner LB, Bennett WA. Secondary malignant tumors of the thyroid gland. Cancer. 1956; 9(2):306–9.
12. Junker K, Egeberg J, Kromann H, Nerup J. An autopsy study of the islets of Langerhans in acute-onset juvenile diabetes mellitus. Acta Pathol Microbiol Scand A. 1977; 85(5):699–706.
13. Wood K, Vini L, Harmer C. Metastases to the thyroid gland: the Royal Marsden experience. Eur J Surg Oncol. 2004; 30(6):83–8.
14. De Ridder M, Sermeus AB, Urbain D, Storme GA. Metastases to the thyroid gland-a report of six cases. Eur J Intern Med. 2003; 14(6):377–9.
15. Yeh HC, Futterweit W, Gilbert P. Micronodulation: ultrasonographic sign of Hashimoto thyroiditis. J Ultrasound Med. 1996; 15(12):813–9.
16. Duggal NM, Horattas MC. Metastatic renal cell carcinoma to the thyroid gland. Endocr Pract. 2008; 14(8):1040–6.
Fig. 1.
Type IA thyroid metastases in a 61-year-old male with lung cancer. Diffuse infiltrative hypoechoic lesion is demonstrated in the entire thyroid gland with multiple microcalcifications (white arrowhead). Diffuse infiltrative lesion reveals mild hypervascularity on color Doppler examination. Normal thyroid parenchyma is entirely replaced by the infiltrative lesion. On histology, obtained by core needle biopsy, malignant cells of metastatic adenocarcinoma with stromal fibrosis replace normal follicular structures entirely on the biopsy specimen (A: transverse plane, B: color Doppler examination, C: Hematoxylin & Eosin stain, ×40, D: cytokeratin stain, × 100).
Fig. 2.
Type IB thyroid metastases in an 86-year-old male with lung cancer. US demonstrates diffuse micronodulation (white arrowheads), which reveals innumerable small linear or curvilinear hypoechoic lesions in entire thyroid gland. Thyroid gland demonstrates marked hypervascularity in color Doppler examination. Histology, obtained by core needle biopsy, demonstrates relatively preserved follicular structures, in which the component of metastatic adenocarcinoma (arrowheads) is less than 10% areas of total biopsy specimen on microscopic evaluation (A: transverse plane, B: color Doppler examination, C: Hematoxylin & Eosin stain, ×100, D: thyroid transcription factor-1 stain, ×100).
Fig. 3.
Type II thyroid metastases in a 54-year-old female with head and neck cancer. A 2 cm suspicious malignant mass is demonstrated in the right mid-thyroid lobe on US. An additional probable benign nodule is observed in the ipsilateral thyroid lobe. Fine needle aspiration revealed metastatic squamous cell carcinoma (A: transverse plane, B: longitudinal plane).
Fig. 4.
Type III thyroid metastases in a 55-year-old male with lung cancer. Three suspicious malignant nodules are demonstrated in the right mid-thyroid lobe (A: transverse plane, arrow), left upper thyroid lobe (B: transverse plane, arrowhead) and left mid-thyroid lobe (C: transverse plane, arrowhead). Fine needle aspiration of a suspicious malignant nodule in the right thyroid lobe (arrow) shows metastatic carcinoma.
Fig. 5.
Type IV thyroid metastases in an 84-year-old male with renal cell carcinoma. Two thyroid nodules in left lobe don't demonstrate suspicious findings. Fine needle aspiration for the larger mass located superiorly (arrow) revealed metastatic carcinoma (A: transverse plane, B: longitudinal plane).
Table 1.
US classification and incidence of thyroid metastasis
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