Abstract
Introduction and Design
Endocrine pathologists, surgeons, and oncologists who manage patients with thyroid carcinomas confront many critical dilemmas. Controversies surrounding diagnostic criteria that distinguish benign from malignant thyroid follicular lesions have been brought to the attention of this community. In this article, we confront another controversy, the definition of a thyroid “capsule” to clarify what constitutes extrathyroidal extension (ETE) and its clinical significance in the management of patients with differentiated thyroid carcinomas.
Results and Conclusion
Our review of the anatomy of the thyroid gland confirms that this structure has no defined anatomical fibrous capsule. Moreover, the presence of adipose tissue within the thyroid gland and its pseudocapsule implies that thyroid tumor within fat tissue cannot be accepted as a criterion of ETE by that thyroid carcinoma. While invasion of skeletal muscle is a more reliable feature of ETE, at the isthmus, these fibers can be normally present within the gland, and this criterion does not have value. This implies that anatomical localization is a critical element in the determination of ETE. Clarification of such issues should be reflected in future revisions of the UICC/AJCC staging criteria to allow more rational management of patients with these increasingly common cancers.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Greene FL, Page DL, Fleming ID, et al. AJCC cancer staging manual. 6th ed. New York: Springer-Verlag; 2002.
Cooper DS, Doherty GM, Haugen BR, et al. The American Thyroid Association Guidelines Taskforce. Management guidelines for patients with thyroid nodules and differentiated thyroid cancer. Thyroid. 2006;16:109–42.
Shaha AR. TNM classification of thyroid carcinoma. World J Surg. 2007;31:879–87.
Dorion D, Lemaire D. Thyroid anatomy, March 5, 2008. http://emedicine.medscape.com/article/835535-overview. Accessed 31 May 2009.
Standring S. Thyroid gland. In: Stranding S, editor. Gray’s anatomy. The anatomical basis of clinical practice. 39th ed. Edinburg: Elsevier Churcill Livingstone; 2005. p. 560–4.
Stewart WB, Rizzolo LL. Embryology and surgical anatomy of the thyroid and parathyroid glands. In: Oertli D, Udelsman R, editors. Surgery of the thyroid and parathyroid glands. New York: Springer; 2007. p. 13–20.
Thyroid: Anatomy and Embryological Development. http://en.wikipedia.org/wiki/Thyroid. Accessed 31 May 2009.
Bliss RD, Gauger PG, Delbridge LW. Surgeon’s approach to the thyroid gland: surgical anatomy and the importance of technique. World J Surg. 2000;24:891–7.
Ghossein R. Update to the College of American Pathologists Reporting on thyroid carcinomas. Head Neck Pathol. 2009;3:86–93.
Komorowski RA, Hanson GA. Occult thyroid pathology in the young adult: an autopsy study of 138 patients without clinical disease. Hum Pathol. 1988;19:689–96.
Rosai J, Kuhn E, Carcangiu ML. Pitfalls in thyroid tumour pathology. Histopathology. 2006;49:107–20.
Hinrichsen C, Lisowski R. Posterior triangle of the neck. In: Hinrichsen C, Lisowski R, editors. Anatomy workbook. Vol 3. Singapore: World Scientific Publishing Company; 2007. p. 3–10.
Ranade AV, Rai R, Pai MM, et al. Anatomical variations of the thyroid gland: possible surgical implications. Singapore Med J. 2008;49:831–4.
Loukas M, Merbs W, Tubbs RS, et al. Levator glandulae thyroideae muscle with three slips. Anat Sci Int. 2008;83:273–6.
Caccetta TP, Kumar A, Ishak H. Lateral aberrant thyroid tissue presenting as a lateral neck mass. ANZ J Surg. 2005;75:1123–4.
DeLellis RA, Lloyd RV, Heitz PU, Eng C. World health organization classification of tumours. Pathology and genetics of tumours of endocrine organs. Lyon: IARC Press; 2004.
Hu A, Clark J, Payne RJ, et al. Extrathyroidal extension in well-differentiated thyroid cancer: macroscopic vs microscopic as a predictor of outcome. Arch Otolaryngol Head Neck Surg. 2007;133:644–9.
Ito Y, Tomoda C, Uruno T, et al. Prognostic significance of extrathyroid extension of papillary thyroid carcinoma: massive but not minimal extension affects the relapse-free survival. World J Surg. 2006;30:780–6.
Jukkola A, Bloigu R, Ebeling T, et al. Prognostic factors in differentiated thyroid carcinomas and their implications for current staging classifications. Endocr Relat Cancer. 2004;11:571–9.
Gluckman JL. Clinical manifestations of thyroid cancer. In: Johnson JT, Gluckman JL, editors. Carcinoma of the thyroid. Oxford, UK: Isis Medical Media; 1999. p. 33–7.
Ito Y, Tomoda C, Uruno T, et al. Minimal extrathyroid extension does not affect the relapse-free survival of patients with papillary thyroid carcinoma measuring 4 cm or less over the age of 45 years. Surg Today. 2006;36:12–8.
Tang W, Kakudo K, Nakamura MD Y, et al. Parathyroid gland involvement by papillary carcinoma of the thyroid gland. Arch Pathol Lab Med. 2002;126:1511–4.
Kakudo K, Tang W, Ito Y, et al. Parathyroid invasion, nodal recurrence, and lung metastasis by papillary carcinoma of the thyroid. J Clin Pathol. 2004;57:245–9.
Ito Y, Kakudo K, Hirokawa M, et al. Clinical significance of extrathyroid extension to the parathyroid gland of papillary thyroid carcinoma. Endocr J. 2009;56:251–5.
Elsheikh TM, Asa SL, Chan JK, et al. Interobserver and intraobserver variation among experts in the diagnosis of thyroid follicular lesions with borderline nuclear features of papillary carcinoma. Am J Clin Pathol. 2008;130:736–44.
Lloyd RV, Erickson LA, Casey MB, et al. Observer variation in the diagnosis of follicular variant papillary thyroid carcinoma. Am J Surg Pathol. 2004;28:1336–40.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Mete, O., Rotstein, L. & Asa, S.L. Controversies in Thyroid Pathology: Thyroid Capsule Invasion and Extrathyroidal Extension. Ann Surg Oncol 17, 386–391 (2010). https://doi.org/10.1245/s10434-009-0832-7
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1245/s10434-009-0832-7