The Use of the Bethesda Terminology in Thyroid Fine-Needle Aspiration Results in a Lower Rate of Surgery for Nonmalignant Nodules

Abstract

The Bethesda system (BS) for reporting thyroid fine-needle aspiration (FNA), which classifies nodules as nondiagnostic (ND), benign (B), atypia/follicular lesion of undetermined significance (AUS/FLUS), suspicious for follicular neoplasm (SFN/FN), suspicious for malignancy (SFM), or malignant (M), uses clinically valuable management guidelines. The authors employed a similar in-house classification system (IS) for thyroid FNAs, using the categories of ND, B, suspicious follicular cells (SFC), follicular lesion/neoplasm (FL/FN), SFM, and M. The authors compared IS and BS, and assessed the utility of BS in clinical practice. A total of 581 nodules with cytological/histological follow-up were examined and indeterminate lesions by BS were reclassified. The sensitivity and specificity for malignancy using IS were similar to that of BS (77% vs 99%). However, when SFN/FN and SFM were both considered positive, the results for IS and BS were as follows: sensitivity, 85% versus 85%; specificity, 87% versus 94%; and diagnostic accuracy, 86% versus 90%, respectively. Discrepancies between cytological and histological data were evident in 35 cases among all categories of BS except AUS/FLUS. The rate of surgery for nonmalignant nodules was lesser (20% vs 9%) by BS. Among 34 AUS/FLUS cases with follow-up data, hypocellularity was the case in 11 (46%) nonneoplastic and 10 (100%) neoplastic nodules. The use of BS results in a lower rate of surgery for nonmalignant nodules even though patients with borderline cytopathologic features are still encountered. AUS/FLUS category can be separated into subgroups according to the factors causing difficulties in the interpretation. There is a need of accumulation of AUS/FLUS cases to do further evaluations and studies.

Atypia of Undetermined Significance in Thyroid Fine-Needle Aspirations: Follow-Up and Outcome Experience in Newfoundland, Canada

“…The wide variation in these rates could be attributed to various factors including study design, patient demographics, technical issues including methods of slide preparation (direct smear vs. LBC slide preparation) and the expertise of the reporting pathologists. Ozluk et al [4], in their analysis of 3,444 thyroid FNAs, attributed the high MR to their study design that included only patients for whom follow-up data were available and who had a nodule > 1 cm in size, since larger nodules are more likely to be malignant [17]. Harvey et al [10] and VanderLaan et al [12] pointed out that there is an inverse relationship between the incidence of cases classified as AUS and the percentage of cases with malignant outcomes.…”

The Bethesda System for Reporting Thyroid Cytopathology : A Five-Year Retrospective Review of One Center Experience

“…However several international studies and reviews have been published in this regard. (6,13,15,(20)(21)(22)(23)(24)(25)(26)(27) This study was performed to study the diagnostic utility of TBSRTC for reporting the rate of thyroid malignancies.…”

Evaluation of Fine-Needle Aspiration of Thyroid Nodules in a Series of 1,100 Patients: Correlation Between Cytology and Histopathology Original Article.

“…Özlük et al reported the highest rate (18 %). In their analysis, they believed that this may have been attributable to the use of a highly selective population which included only those patients for whom cytological or histological follow-up data were available and/or to the geographic uniqueness of their population [8]. A rate of 0.8 to 9 % suspicious malignancy, including a follicular neoplasia rate of up to 11.6 %, has been documented in the literature.…”

“…They also emphasized that changes, such as hyalinization, calcification, and intracystic papillary hyperplasia, may reflect atypical nuclear changes [8].…”

“…For the diagnosis of mismatch, Özlük et al [8] considered histopathological subtyping to be an important element when confronted with follicular variants of papillary thyroid carcinoma, and to a lesser extent, the uncertain potential of differentiated groups. They also emphasized that changes, such as hyalinization, calcification, and intracystic papillary hyperplasia, may reflect atypical nuclear changes [8].…”