Abstract
Although approximately 30% of FNAs result in indeterminate diagnoses, a comprehensive diagnostic approach to thyroid follicular cell tumors was provided by the Bethesda system. When histological type is uncertain, risk stratification based on cellular atypia and architectural atypia is the most objective approach and basic classification schema that covers all histological types of primary thyroid carcinomas and other benign conditions. The Bethesda system risk stratifies the indeterminate cytological category into three subcategories morphologically: low risk, intermediate risk, and high risk [1, 2]. Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance (AUS/FLUS) is the low risk indeterminate category, and all histological types of malignancy are found on histology. The Bethesda system recommended subcategorization of AUS/FLUS nodules, which are detailed and illustrated in this chapter.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Ali SZ, Cibas ES, editors. The Bethesda system for reporting thyroid cytopathology. Definitions, criteria and explanatory notes. New York: Springer; 2010. p. 1–166.
Ali SZ, Cibas ES. The Bethesda system for reporting thyroid cytopathology: definitions, criteria and explanatory notes. New York, NY: Springer; 2018. p. 1–236.
Kakudo K, Higuchi M, Hirokawa M, et al. Thyroid FNA cytology in Asian practice-active surveillance for indeterminate thyroid nodules reduces overtreatment of thyroid carcinomas. Cytopathology. 2017;28:455–66.
Bychkov A, Keelawat S, Agarwal S, et al. Impact of noninvasive follicular thyroid neoplasm with papillary-like nuclear features on the Bethesda system for reporting thyroid cytopathology: a multi-institutional study in five Asian countries. Pathology. 2018;50:411–7.
Renshaw AA. Focal features of papillary carcinoma of the thyroid in fine needle aspiration material are strongly associated with papillary carcinoma at resection. Am J Clin Pathol. 2002;118:208–10.
Weber D, Brainard J, Chen L. Atypical epithelial cells, cannot exclude papillary carcinoma, in fine needle aspiration of the thyroid. Acta Cytol. 2008;52:320–4.
Abele JS, Levine RA. Diagnostic criteria and risk-adapted approach to indeterminate thyroid cytodiagnosis. Cancer Cytopathol. 2010;118:415–22.
Olson MT, Clark DP, Erozan YS, et al. Spectrum of risk of malignancy in subcategories of ‘atypia of undetermined significance’. Acta Cytol. 2011;55:518–25.
Hyeon J, Ahn S, Shin JH, et al. The prediction of malignant risk in the category ‘atypia of undetermined significance/follicular lesion of undetermined significance’ of the Bethesda System for Reporting Thyroid Cytopathology using subcategorization and BRAF mutation results. Cancer Cytopathol. 2014;122:368–76.
Ohori NP, Schoedel KE. Variability in the atypia of undetermined significance/follicular lesion of undetermined significance diagnosis in the Bethesda system for reporting thyroid cytopathology: Sources and recommendations. Acta Cytol. 2011;55:492–8.
Cibas ES, Baloch ZW, Fellegara G, et al. A prospective assessment defining the limitations of thyroid nodule pathologic evaluation. Ann Intern Med. 2013;159:325–32.
Faquin WC, Cibas ES, Renshaw AA. “Atypical” cells in fine-needle aspiration biopsy specimens of benign thyroid cysts. Cancer Cytopathol. 2005;105:71–9.
Renshaw AA. “Histiocytoid” cells in fine-needle aspirations of papillary carcinoma of the thyroid. Frequency and significance of an under-recognized cytologic pattern. Cancer Cytopathol. 2002;96:240–3.
Haugen BR, Alexander EK, Bible KC, et al. American Thyroid Association management guidelines for adult patients with thyroid nodules and differentiated thyroid cancer. Thyroid. 2015;26:1–134.
VanderLaan PA, Krane JF, Cibas ES. The frequency of ‘Atypia of undetermined significance’ interpretation is negatively correlated with histologically proven malignant outcomes. Acta Cytol. 2011;55:512–7.
Renshaw AA, Gould EW. Reducing indeterminate thyroid FNAs. Cancer Cytopathol. 2015;123:237–43.
Krane JF, VanderLaan PA, Faquin WC, et al. The atypia of undetermined significance/follicular lesion of undetermined significance: malignant ratio: a proposed performance measure for reporting in the Bethesda System for thyroid cytopathology. Cancer Cytopathol. 2012;120:111–6.
VanderLaan PA, Marqusee E, Krane JF. Clinical outcome for atypia of undetermined significance in thyroid fine-needle aspirations: should repeated FNA be the preferred initial approach? Am J Clin Pathol. 2011;135(5):770–5.
Baloch Z, LiVolsi VA, Jain P, Jain R, Aljada I, Mandel S, Langer JE, Gupta PK. Role of repeat fine-needle aspiration biopsy (FNAB) in the management of thyroid nodules. Diagn Cytopathol. 2003;29:203–6.
Higuchi M, Hirokawa M, Kanematsu R, et al. Impact of the modification of the diagnostic criteria in the 2017 Bethesda system for reporting thyroid cytopathology: a report of a single institution in Japan. Endocr J. 2018; https://doi.org/10.1507/endocrj.EJ18-0290.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2019 Springer Nature Singapore Pte Ltd.
About this chapter
Cite this chapter
Kakudo, K., Liu, Z., Ren, Y., Wakasa, T. (2019). Diagnostic Criteria for AUS/FLUS in the Second Edition Bethesda System for Reporting Thyroid Cytopathology. In: Kakudo, K. (eds) Thyroid FNA Cytology. Springer, Singapore. https://doi.org/10.1007/978-981-13-1897-9_23
Download citation
DOI: https://doi.org/10.1007/978-981-13-1897-9_23
Published:
Publisher Name: Springer, Singapore
Print ISBN: 978-981-13-1896-2
Online ISBN: 978-981-13-1897-9
eBook Packages: MedicineMedicine (R0)