Fine needle aspiration and the Bethesda system: Correlation with histopathology in 1,228 surgical patients

Incidental Thyroid Malignancy in Surgical Patients With Benign Thyroid Disease

INTRODUCTION

The rate of incidental thyroid malignancy (ITM) has increased in recent decades. However, the factors associated with ITM remain uncertain. This study analyzes the rate of ITM in patients after surgical resection for benign thyroid disease (BTD) without preoperative suspicion of thyroid malignancy and its associated sociodemographic factors.

MATERIALS AND METHODS

A retrospective study of prospectively collected data reviewed data from 2528 patients who underwent initial thyroidectomy for BTD at a tertiary academic medical hospital between 2011 and 2022. Patients were excluded if they had a known history of thyroid cancer, radiation exposure, suspicious thyroid ultrasound features, and/or fine needle aspiration results. ITM rate was analyzed along with patient demographics, body mass index (BMI), tumor size, and invasive features.

RESULTS

Among 345 patients with BTD (mean 53.6 y, SD = 14.5), 22.9% (79/345) had ITM on final histopathology. Most patients were women (87.0%), White (87.0%), and Hispanic (56.8%), with an average BMI of 29.6 (SD = 6.56). BTD type was associated with ITM (P < 0.001), with nontoxic multinodular goiter exhibiting the highest incidence (36.0%). Higher BMI emerged as a predictor of higher rate of ITM (OR = 1.057, P = 0.007). Other sociodemographic variables did not show significant associations.

CONCLUSIONS

The study identified a higher rate of ITM than previously reported as well as an association between higher BMI and increased rate of ITM. This highlights a potential link between obesity and ITM not previously identified. Patients with higher BMI and BTD may benefit from further surveillance.

Molecular-derived risk of malignancy and the related positive call rate of indeterminate thyroid cytology diagnoses as quality metrics for individual cytopathologists

BACKGROUND

Indeterminate thyroid cytopathology diagnoses represent differing degrees of risk that are corroborated by follow-up studies. However, traditional cytologic-histologic correlation may overestimate the risk of malignancy (ROM) because only a subset of cases undergo resection. Alternatively, some molecular tests provide probability of malignancy data to calculate the molecular-derived risk of malignancy (MDROM) and the positive call rate (PCR). The authors investigated MDROMs and PCRs of indeterminate diagnoses for individual cytopathologists as quality metrics.

METHODS

This study was approved by the Department of Pathology Quality Improvement Program. Thyroid cytopathology diagnoses and ThyroSeq v3 results were retrieved for each cytopathologist for a 2-year period with at least 3 years of follow-up for the atypia of undetermined significance (AUS), follicular neoplasia (FN), and follicular neoplasia, oncocytic-type (ONC) cytopathologic diagnoses. MDROMs and PCRs were compared with reference ROMs and cytologic-histologic correlation outcomes.

RESULTS

The overall MDROMs (and ranges for cytopathologists) for the AUS, FN, and ONC categories were 13.4% (range, 5.8%-20.8%), 28.1% (range, 22.1%-36.7%), and 27.0% (range, 19.5%-41.5%), respectively, and most individual cytopathologists' MDROMs were within reference ROM ranges. However, PCRs more effectively parsed the differences in cytopathologists' ROM performance. Although the overall PCRs were not significantly different across cytopathologists (p = .06), the AUS PCRs were quite different (p = .002). By cytologic-histologic correlation, six of 55 resected cases (10.9%) were falsely negative, and there were no false-positive cases.

CONCLUSIONS

MDROMs and PCRs evaluate concordance with reference ROMs and with one another and provide individual feedback, which potentially facilitates quality improvement.

Accuracy and diagnostic performance of the Bethesda system for reporting thyroid cytopathology in a tertiary endocrine surgical referral center in Belgium

BACKGROUND

The Bethesda System for Reporting Thyroid Cytopathology is a commonly used classification for fine needle aspiration (FNA) cytology of suspicious thyroid nodules. The risk of malignancy (ROM) for each category has recently been analyzed in three international databases. This paper compares the diagnostic performance of the Bethesda classification in a high-volume referral center in Belgium.

METHODS

All consecutive thyroid procedures were registered in a prospective database from January 2010 till August 2022. Patient and surgical characteristics, preoperative Bethesda categories, and postoperative pathology results were analyzed.

RESULTS

Out of 2219 consecutive thyroid procedures, 1226 patients underwent preoperative FNA. Papillary thyroid cancer was the most prevalent malignancy (N = 119, 70.4%), followed by follicular (N = 17, 10.1%) and medullary thyroid cancer (N = 15, 8.9%). Micropapillary thyroid cancer was incidentally found in 46 (3.8%) patients. Bethesda categories I, II, III, IV, V, and VI, respectively, represented 250 (20.4%; ROM 4.4%), 546 (44.5%; ROM 3.8%), 96 (7.8%; ROM 20.8%), 231 (18.8%; ROM 15.2%), 62 (5.1%; ROM 72.6%), and 41 (3.3%; ROM 90.2%) patients. Overall ROM was 13.8%. An negative predictive value (NPV) of 96.2% was found. Overall specificity was 64.2% with a positive predictive value (PPV) of 31.9%. Diagnostic accuracy was 67.8%. Compared to international databases (CESQIP, EUROCRINE, and UKRETS), ROM in this study appeared lower for Bethesda category IV (15.2 vs. 26.7% and p = 0.612).

CONCLUSION

Despite being validated in numerous studies, ROM based on preoperative FNA cytology classified according to the Bethesda classification may vary among surgical centers and countries as this study reveals a higher NPV and lower PPV.

Examining the impact of several factors including COVID-19 on thyroid fine-needle aspiration biopsy

OBJECTIVE

The study explores various factors, including coronavirus disease 2019 (COVID-19) history and vaccination status, that influence the classification value of ultrasonography-guided thyroid fine needle aspiration biopsy (TFNAB) by comparing non-diagnostic (Bethesda-I) and diagnostic (Bethesda II-VI) results.

METHODS

We conducted a retrospective observational study in a high-volume tertiary care center involving patients who underwent TFNAB from November 2022 to April 2023. The study retrospectively analyzed the cytopathology of 482 thyroid nodules. Patients were categorized into non-diagnostic (n = 136) and Diagnostic groups (n = 346) based on TFNAB. A comprehensive set of parameters was examined, including demographic, anthropometric and clinical data, thyroid ultrasonography findings, COVID-19 history and immunization status.

RESULTS

The mean age was 55.1 ± 12.1 years in the non-diagnostic group and 53.5 ± 13 years in the Diagnostic group (p = .223). 75.7% (n = 103) of the non-Diagnostic group and 82.9% (n = 287) of the Diagnostic group were male (p = .070). The mean nodule longitudinal diameter of the Diagnostic group was significantly higher than that of the non-diagnostic group (p = .015). The TIRADS score of the nodules showed a statistical difference between the groups (p = .048). The groups had no significant differences regarding other ultrasonographic parameters and COVID-19-related variables.

CONCLUSION

It can be assumed that when the longitudinal diameter of the thyroid nodule is small and in TIRADS categories other than the TIRADS3 category, TFNAB is less likely to be diagnostic. However, future research may be needed to confirm these findings and uncover any long-term effects of COVID-19 or vaccines on thyroid nodule diagnostics.

The national rate of malignancy among Bethesda III, IV, and V thyroid nodules is higher than expected: A NSQIP analysis

BACKGROUND

The Bethesda System for Reporting Thyroid Cytopathology was formalized in 2007 to stratify cytologic specimens based on their risk of malignancy. Several studies have reported significant variations between their institutional rate of malignancy compared to the Bethesda System for Reporting Thyroid Cytopathology. The objective of this study was to determine the national rate of malignancy for Bethesda III, Bethesda IV, and Bethesda V thyroid nodules.

METHODS

From 2016 to 2019, patients with preoperative thyroid cytopathology and pathology results in National Surgical Quality Improvement database were included. The rate of malignancy was compared to the median the Bethesda System for Reporting Thyroid Cytopathology 2017, and risk factors associated with malignancy were identified for Bethesda III, Bethesda IV, and Bethesda V specimens.

RESULTS

In total, 13,121 patients with preoperative cytopathology and postresection pathology were identified. The national rate of malignancy was significantly higher than the Bethesda System for Reporting Thyroid Cytopathology 2017 for Bethesda III (36.2% vs 12.0%, P < .01), Bethesda IV (36.7% vs 25.0%, P < .01), and Bethesda V (91.1% vs 52.5%, P < .01) specimens. Male sex was significantly associated with malignancy in Bethesda III, Bethesda IV, and Bethesda V nodules (Bethesda III, odds ratio: 1.20, [1.01-1.42]; Bethesda IV, odds ratio: 1.47, [1.27-1.71]; Bethesda V, odds ratio: 1.28, [1.03-1.58]). Younger age was associated with malignancy in Bethesda III patients under 55 (odds ratio: 1.23, [1.06-1.42]), Bethesda IV patients under 42 (odds ratio: 1.23, [1.06-1.43]), and Bethesda V patients aged less than 47 (odds ratio: 1.38, [1.15-1.67]).

CONCLUSIONS

This is the largest cohort study to describe the national rate of malignancy for Bethesda III, IV, and V specimens in the United States. These results reveal the national rate of malignancy is higher than the implied rate of malignancy reported to patients based on the Bethesda System for Reporting Thyroid Cytopathology. We recommend counseling patients regarding this increased rate of malignancy to set appropriate expectations after surgical intervention.

Malignancy Rate of Bethesda Class III Thyroid Nodules Based on the Presence of Chronic Lymphocytic Thyroiditis in Surgical Patients

BACKGROUND

Hashimoto's thyroiditis (HT), also known as chronic lymphocytic thyroiditis (CLT), may interfere with the accurate cytological diagnosis of thyroid nodules. Recently, HT has been considered a premalignant condition for thyroid cancer development. The diagnosis of atypia of undetermined significance/follicular lesions of undetermined significance (AUS/FLUS) thyroid nodules is challenging and evidence for the malignancy risk of AUS/FLUS thyroid nodules coexisting with CLT is scarce. Therefore, we assessed the malignancy risk of AUS/FLUS thyroid nodules according to the presence of background CLT.

METHODS

This study included 357 surgically resected thyroid nodules with AUS/FLUS cytology. Cases with concomitant malignant nodules were excluded. CLT was defined based on the pathologic report after thyroid surgery.

RESULTS

Among 357 tumors, 130 tumors (36%) were confirmed to have coexisting CLT, and 170 tumors (48%) were determined to be malignant after thyroidectomy. Malignancy rates were similar in both groups (48% in each) regardless of background CLT (62/130 with CLT vs. 108/227 without CLT). In the group with CLT, thyroiditis was more frequent in the final pathology (12% with CLT vs. 1% without CLT, P = 0.003). In multivariate analysis, positive BRAF^V600E mutation, highly suspicious sonographic features (K-TIRADS 5), and smaller thyroid nodules were significant factors for thyroid malignancies.

CONCLUSION

The malignancy rate of thyroid nodules with AUS/FLUS cytology was comparable irrespective of the presence of underlying CLT.