Objectives: To determine the frequency of category 3 (atypia of undetermined significance [AUS]/follicular lesion of undetermined significance [FLUS]), category 4 (follicular neoplasm), and category 5 (suspicious for malignancy) of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), the risk of malignancy (ROM) and the risk of neoplasia (RON) in these categories. Study Design: A retrospective 6-year audit of 4,532 thyroid fine-needle aspirations (FNA) reported as per the TBSRTC from a single institution with cytohistological correlation in 335 cases. Results: The frequency of categories 3, 4, and 5 was 2.5, 3.9, and 0.5%, respectively; the upper and lower bound estimates of ROM being 58.3, 23.6, 75% and 5.1, 5, and 12.5%, respectively. AUS/FLUS (n = 116) cases were subcategorized as AUS, AUS-HC (Hürthle cell), AUS-PTC (AUS-papillary thyroid carcinoma not excluded), FLUS, FLUS-FH (favor hyperplasia), FLUS-HC, and FLUS-PTC. The AUS/FLUS malignancy ratio was 1:3.8. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of FNA thyroid was 80.5, 85.9, 80.7, 85.7, and 82.4%, respectively. Conclusion: Implementation of TBSRTC aided in achieving internal quality control in reporting thyroid FNA cytology. The AUS/FLUS frequency was 2.5%, which is at the lower range of the recommended rate and was associated with a higher than recommended upper bound estimate, but a comparable lower bound estimate of ROM.

Keywords:
Thyroid, Fine-needle aspiration, The Bethesda System for Reporting Thyroid Cytopathology, Indeterminate thyroid nodule, Risk of malignancy, Risk of neoplasia
1.
Nguyen GK, Lee MW, Ginsberg J, Wragg T, Bilodeau D: Fine-needle aspiration of the thyroid: an overview. Cytojournal 2005;2:12.
2.
Cibas ES, Ali SZ: The Bethesda System for Reporting Thyroid Cytopathology. Am J Clin Pathol 2009;132:658-665.
3.
Bongiovanni M, Spitale A, Faquin WC, Mazzucchelli L, Baloch ZW: The Bethesda System for Reporting Thyroid Cytopathology: a meta-analysis. Acta Cytol 2012;56:333-339.
4.
Mondal SK, Sinha S, Basak B, Roy DN, Sinha SK: The Bethesda system for reporting thyroid fine needle aspirates: a cytologic study with histologic follow-up. J Cytol 2013;30:94-99.
5.
Jo VY, Stelow EB, Dustin SM, Hanley KZ: Malignancy risk for fine-needle aspiration of thyroid lesions according to the Bethesda System for Reporting Thyroid Cytopathology. Am J Clin Pathol 2010;134:450-456.
6.
Wu HH, Rose C, Elsheikh TM: The Bethesda System for Reporting Thyroid Cytopathology: an experience of 1,382 cases in a community practice setting with the implication for risk of neoplasm and risk of malignancy. Diagn Cytopathol 2012;40:399-403.
7.
Fatman L, Michelow P: Thyroid cytopathology with an emphasis on the ‘atypical cells of uncertain significance' category: a 3-year audit with cytohistologic correlation. Acta Cytol 2015;59:17-25.
8.
Cochand-Priollet B, Schmitt FC, Tötsch M, Vielh P: The Bethesda terminology for reporting thyroid cytopathology: from theory to practice in Europe. Acta Cytol 2011;55:507-511.
9.
Yang J, Schnadig V, Logrono R, et al: Fine-needle aspiration of thyroid nodules: a study of 4703 patients with histologic and clinical correlations. Cancer 2007;111:306-315.
10.
MacDonald L, Yazdi HM: Fine needle aspiration biopsy of Hashimoto's thyroiditis. Sources of diagnostic error. Acta Cytol 1999;43:400-406.
11.
Schmidt T, Riggs MW, Speights VO Jr: Significance of nondiagnostic fine-needle aspiration of the thyroid. South Med J 1997;90:1183-1186.
12.
McHenry CR, Walfish PG, Rosen IB: Non-diagnostic fine needle aspiration biopsy: a dilemma in management of nodular thyroid disease. Am Surg 1993;59:415-419.
13.
Park JH, Yoon SO, Son EJ, Kim HM, Nahm JH, Hong S: Incidence and malignancy rates of diagnoses in the Bethesda system for reporting thyroid aspiration cytology: an institutional experience. Korean J Pathol 2014;48:133-139.
14.
Faquin WC, Wong LQ, Afrogheh AH, Ali SZ, Bishop JA, Bongiovanni M, Pusztaszeri MP, et al: Impact of reclassifying noninvasive follicular variant of papillary thyroid carcinoma on the risk of malignancy in The Bethesda System for Reporting Thyroid Cytopathology. Cancer Cytopathol 2016;124:181-187.
15.
Harvey AM, Mody DR, Amrikachi M: Thyroid fine-needle aspiration reporting rates and outcomes before and after Bethesda implementation within a combined academic and community hospital system. Arch Pathol Lab Med 2013;137:1664-1668.
16.
Onder S, Firat P, Ates D: The Bethesda System for Reporting Thyroid Cytopathology: an institutional experience of the outcome of indeterminate categories. Cytopathology 2014;25:177-184.
17.
Gocun PU, Karakus E, Bulutay P, Akturk M, Akin M, Poyraz A: What is the malignancy risk for atypia of undetermined significance? Three years' experience at a university hospital in Turkey. Cancer Cytopathol 2014;122:604-610.
18.
Strickland KC, Howitt BE, Marqusee E, Alexander EK, Cibas ES, Krane JF, Barletta JA: The impact of noninvasive follicular variant of papillary thyroid carcinoma on rates of malignancy for fine-needle aspiration diagnostic categories. Thyroid 2015;25:987-992.
19.
Olson MT, Clark DP, Erozan YS, Ali SZ: Spectrum of risk of malignancy in subcategories of ‘atypia of undetermined significance'. Acta Cytol 2011;55:518-525.
20.
Ratour J, Polivka M, Dahan H, Hamzi L, Kania R, Dumuis ML, et al: Diagnosis of follicular lesions of undetermined significance in fine-needle aspirations of thyroid nodules. J Thyroid Res 2013;2013:250347.
21.
Kholová I, Ludvíková M: Thyroid atypia of undetermined significance or follicular lesion of undetermined significance: an indispensable Bethesda 2010 diagnostic category or waste garbage? Acta Cytol 2014;58:319-329.
22.
McKee S, Wu H, Wang X, Cramer H, Lin J, Chen S: Hürthle cell neoplasms diagnosed by fine needle aspiration are not associated with an increased risk of malignancy. Acta Cytol 2014;58:235-238.
© 2017 S. Karger AG, Basel
2017
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.