Thyroid Atypia of Undetermined Significance or Follicular Lesion of Undetermined Significance: An Indispensable Bethesda 2010 Diagnostic Category or Waste Garbage?

Abstract

Objective: The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) was introduced in thyroid cytology in 2007 and is now generally accepted. BSRTC categories include a morphologic description and risk of malignancy as well as follow-up suggestions in each group. However, the category entitled ‘atypia of undetermined significance or follicular lesion of undetermined significance' (AUS/FLUS) is problematic. This category is heterogeneous and has been overused so far. Study Design: Twenty-six studies were included in a meta-analysis. In addition to AUS/FLUS percentage, we analysed repeated AUS/FLUS percentage, cytological and histological correlations, and risk of malignancy and neoplasm for AUS/FLUS. Furthermore, stratification, inter- and intra-observer variability, and the possibility of a switch to another category and its clinical consequences were reviewed. Results: Out of a total of 81,833 cases, AUS/FLUS accounted for 10.9%, with a 34% risk of malignancy. Persistent AUS/FLUS was found in 21.6% in repeated cytology. Cytohistological correlation was analysed from 16 studies (4,964 cases), revealing 10.4% as AUS/FLUS and a 21.5% risk of malignancy. Conclusions: An AUS/FLUS category seems to be currently reasonable with clearly defined cytomorphological criteria which do not correspond unequivocally with those of the other categories. An AUS/FLUS category is justified and possible means of its improvement with immunohistochemistry, molecular analysis and imaging are discussed.

Kliniczne znaczenie rozpoznania zmiany pęcherzykowej bliżej nieokreślonej (grupa III wg Systemu Bethesda) w biopsji aspiracyjnej cienkoigłowej (BAC)

“…Other researchers indicated that repeat FNA after initial DC III was performed in 6.8% [7] and 33% [11] of cases, and a meta-analysis of 10 studies demonstrated an average performance of repeat FNA ranging from 9.39% to 20.5% [10]. In the study repeat FNA was performed 26 times, which comprises 46.4% [15].…”

“…The possibility of consultation between the competent pathologists regarding aspirates examination is essential. Most of the shown analyses concern the work of cytopathologists or pathologists that deal with cytological diagnostics of the thyroid on a daily basis [1,4,10,11]. The authors of one of the large studies base the initial diagnostics on the work of screeners.…”

“…They received 135 diagnoses of malignancies (38.6%), and after subsequent FNA with DC III 12 patients had surgical treatment, obtaining four diagnoses of malignancies [7]. Meta-analysis based on 26 studies showed 34% risk of malignancy [10]. Wu et al reported 7% risk of malignancy [5].…”

Podejrzenie nowotworu pęcherzykowego czy nowotwór pęcherzykowy? Dylemat patologa i chirurga

“…The risk of neoplasia, and especially the risk of malignancy, presented by the researchers is greatly varied [2,17,18]. These major discrepancies may result from the number of analysed cases, from 97 FNAs [13] to more than 16 thousand (16,656 in our study).…”

“…Moreover, the implementation of BSRTC allows comparison of data concerning the risk of malignancy between institutions and the assessment of the system's effectiveness and capability [2][3][4][5][6][7] (Table I).…”