AACE/ACE/AME Guidelines AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS, AMERICAN COLLEGE OF ENDOCRINOLOGY, AND ASSOCIAZIONE MEDICI ENDOCRINOLOGI MEDICAL GUIDELINES FOR CLINICAL PRACTICE FOR THE DIAGNOSIS AND MANAGEMENT OF THYROID NODULES – 2016 UPDATE APPENDIX

Thyroid nodules are detected in up to 50 to 60% of healthy subjects. Most nodules do not cause clinically significant symptoms, and as a result, the main challenge in their management is to rule out malignancy, with ultrasonography (US) and fine-needle aspiration (FNA) biopsy serving as diagnostic cornerstones. The key issues discussed in these guidelines are as follows: (1) US-based categorization of the malignancy risk and indications for US-guided FNA (henceforth, FNA), (2) cytologic classification of FNA samples, (3) the roles of immunocytochemistry and molecular testing applied to thyroid FNA, (4) therapeutic options, and (5) follow-up strategy. Thyroid nodule management during pregnancy and in children are also addressed. On the basis of US features, thyroid nodules may be categorized into 3 groups: low-, intermediateand high-malignancy risk. FNA should be considered for nodules ≤10 mm diameter only when suspicious US signs are present, while nodules ≤5 mm should be monitored rather than biopsied. A classification scheme of 5 categories (nondiagnostic, benign, indeterminate, suspicious for malignancy, or malignant) is recommended for the cytologic report. Indeterminate lesions are further subdivided into 2 subclasses to more accurately stratify the risk of malignancy. At present, no single cytochemical or genetic marker can definitely rule out malignancy in indeterminate nodules. Nevertheless, these tools should be considered together with clinical data, US signs, elastographic pattern, or results of other imaging techniques to improve the management of these lesions. Most thyroid nodules do not require any treatment, and levothyroxine (LT4) suppressive therapy is not recommended. Percutaneous ethanol injection (PEI) should be the first-line treatment option for relapsing, benign cystic lesions, while US-guided thermal ablation treatments may be considered for solid or mixed symptomatic benign thyroid nodules. Surgery remains the treatment of choice for malignant or suspicious nodules. The present document updates previous guidelines released in 2006 and 2010 by the American Association From 1Professor of Medicine, Mayo Clinic College of Medicine, Past President, American Association of Clinical Endocrinologists, Past President, American Thyroid Association; 2Director, Department of Endocrinology and Metabolism, Regina Apostolorum Hospital, Via San Francesco 50, 00041, Albano, Rome (Italy); 3Endocrine Division, Harvard Vanguard Medical Associates, Boston, Massachusetts, Division of Endocrinology, Beth Israel Deaconess Medical Center, Boston, Massachusetts; 4Endocrinology Associates, PA, Professor of Medicine, College of Medicine, University of Arizona (Phoenix and Tucson Campuses); 5Co-Director Memorial Center for Integrative Endocrine Surgery; 6Professor of Endocrinology at the University of Southern Denmark, Consultant Physician at the Department of Endocrinology and Metabolism at Odense University Hospital; 7Professor and Head Division of Endocrinology and Metabolism, Department of Oncology & Arnie Charbonneau Cancer Institute, Cummings School of Medicine, University of Calgary, Richmond Road Diagnosis and Treatment Centre (RRDTC), 1820 Richmond RD SW, Calgary AB T2T5C7; 8Director of the Endocrinology Unit, Centro Palmer, Reggio Emilia, Via Fratelli Cervi 75/b, Italy; 9Professor, University of Pisa, Section of Endocrinology, Department of Clinical and Experimental Medicine. *A complete list of the AACE/ACE/AME Thyroid Nodule Task Force can be found in the Acknowledgements section of this publication. Address correspondence to American Association of Clinical Endocrinologists, 245 Riverside Ave, Suite 200, Jacksonville, FL 32202. E-mail: publications@aace.com. DOI:10.4158/EP161208.GL To purchase reprints of this article, please visit: www.aace.com/reprints. Copyright © 2016 AACE. Thyroid Nodule Management, Endocr Pract. 2016;22(Suppl 1) 3 of Clinical Endocrinologists (AACE) and Associazione Medici Endocrinologi (AME).