The Bethesda system for reporting thyroid cytopathology: a single-center experience over 5 years

Diagnostic Accuracy of Fine-Needle Biopsy in the Detection of Thyroid Malignancy: A Systematic Review and Meta-analysis

Importance

Fine-needle biopsy (FNB) became a critical part of thyroid nodule evaluation in the 1970s. It is not clear how diagnostic accuracy of FNB has changed over time.

Objective

To conduct a systematic review and meta-analysis estimating the accuracy of thyroid FNB for diagnosis of malignancy in adults with a newly diagnosed thyroid nodule and to characterize changes in accuracy over time.

Data Sources

PubMed, SCOPUS, and Cochrane Central Register of Controlled Trials were searched from 1975 to 2020 using search terms related to FNB accuracy in the thyroid.

Study Selection

English-language reports of cohort studies or randomized trials of adult patients undergoing thyroid FNB with sample size of 20 or greater and using a reference standard of surgical histopathology or clinical follow-up were included. Articles that examined only patients with known thyroid disease or focused on accuracy of novel adjuncts, such as molecular tests, were excluded. Two investigators screened each article and resolved conflicts by consensus. A total of 36 of 1023 studies met selection criteria.

Data Extraction and Synthesis

The MOOSE guidelines were used for data abstraction and assessing data quality and validity. Two investigators abstracted data using a standard form. Studies were grouped into epochs by median data collection year (1975 to 1990, 1990 to 2000, 2000 to 2010, and 2010 to 2020). Data were pooled using a bivariate mixed-effects model.

Main Outcomes and Measures

The primary outcome was accuracy of FNB for diagnosis of malignancy. Accuracy was hypothesized to increase in later time periods, a hypothesis formulated prior to data collection.

Results

Of 16 597 included patients, 12 974 (79.2%) were female, and the mean (SD) age was 47.3 (12.9) years. The sensitivity of FNB was 85.6% (95% CI, 79.9-89.5), the specificity was 71.4% (95% CI, 61.1-79.8), the positive likelihood ratio was 3.0 (95% CI, 2.3-4.1), and the negative likelihood ratio was 0.2 (95% CI, 0.2-0.3). The area under the receiver operating characteristic curve was 86.1%. Epoch was not significantly associated with accuracy. None of the available covariates could explain observed heterogeneity.

Conclusions and Relevance

Accuracy of thyroid FNB has not significantly changed over time. Important developments in technique, preparation, and interpretation may have occurred too heterogeneously to capture a consistent uptrend over time. FNB remains a reliable test for thyroid cancer diagnosis.

Patient Compliance With Surveillance of Thyroid Nodules Classified as Atypia of Undetermined Significance

OBJECTIVE

To determine whether thyroid nodule surveillance compliance is influenced by patient demographics or plan type.

STUDY DESIGN

Retrospective case series from 2010 to 2018.

SETTING

United States Military Health System.

METHODS

There were 481 patients with a thyroid nodule fine-needle aspiration classified as atypia of undetermined significance for whom treatment and follow-up information were available. Demographic information and surveillance plan type were extracted from the medical record and statistical analysis was performed to determine whether these characteristics influenced compliance rates.

RESULTS

A total of 289 nodules were surveilled and 192 diagnostic lobectomies were performed. An initial surveillance plan was documented in 93% (268/289) and 86% (231/268) complied. The most common plans were repeat biopsy in 78% (210/268) or ultrasound in 20% (53/268). A second plan was documented in 88% (204/231) of those who complied with the first. The most common second plans were ultrasound in 87% (178/204) or repeat biopsy in 8% (17/204). Compliance with the second plan was 64% (130/204), significantly lower than with the first (OR 3.6, 95% CI: [2.3, 5.6], P < .0001). Only 45% (130/289) were surveilled twice. Age and gender did not significantly affect compliance rates. Compliance with primary care ultrasound surveillance was 40% (21/52), significantly lower than with a specialist (77% [137/179]; OR 4.8, 95% CI: [2.5, 9.3, P < .0001).

CONCLUSION

Compliance with surveillance of thyroid nodules classified as atypia of undetermined significance was poor in this military cohort. Ultrasound surveillance by a specialist may be more reliable than with primary care.

Cytomorphological categorization of thyroid lesions according to the bethesda system for reporting thyroid cytology and correlation with their histological outcome: An indian oncology centre experience

Objective:

Material and Methods:

Results:

Conclusion:

Diagnostic Lobectomy for Bethesda III Thyroid Nodules: Pathological Outcomes and Risk Factors for Malignancy

OBJECTIVE

An indeterminate thyroid nodule fine-needle aspiration (FNA) presents a unique dilemma. We evaluated our institution's experience with Bethesda III thyroid nodules, including the risk of malignancy (ROM) of these nodules removed for diagnostic lobectomy and radiologic and clinical risk factors for malignancy.

STUDY DESIGN

Retrospective chart review.

SETTING

San Antonio Military Medical Center (SAMMC; 483 bed Military Treatment Facility and Level 1 Trauma Center).

METHODS

We identified all patients with a Bethesda III thyroid FNA at our institution from 2010 to 2018 and determined which nodules were removed. The final histological diagnosis was recorded. Whether or not age, gender, body mass index (BMI), race, nodule size, margin regularity, rate of nodule growth, vascularity, internal calcifications, family history of thyroid cancer, personal history of radiation, and history of repeated AUS/FLUS on FNA had a significant impact on malignancy risk was evaluated with chi square and rank sum Wilcoxon tests.

RESULTS

492 patients had 1 or more AUS result. 52% (258/492) underwent repeat FNA. This resulted in Bethesda II or III in 90% (232/258). In 10% (26/258), the repeat FNA resulted in a higher Bethesda grade. 183 lobectomies were performed on the side containing an AUS nodule. The malignancy percentage was 38.3% (70/183). Age less than 30 was the only variable showing statistical significance for increased risk of malignancy (P = .04).

CONCLUSION

The ROM of nodules characterized as AUS/FLUS on FNA may be higher than expected. Age may be a better predictor of malignancy than repeat FNA.

High risk of malignancy in cases with atypia of undetermined significance on fine needle aspiration of thyroid nodules even after exclusion of NIFTP

BACKGROUND

Fine needle aspiration cytopathology (FNAC) is the most reliable tool for evaluating thyroid nodules. However, diagnosing Bethesda category III, atypia/follicular lesion of undetermined significance (AUS/FLUS), is a major limitation. The aim of this study was to evaluate the risk of malignancy (RoM) in AUS/FLUS nodules. A systematic review was also carried out analyzing the largest series.

METHODS

Totally 1750 cases (9%) diagnosed with AUS/FLUS were evaluated retrospectively out of 19 392 cases within last 13 years. All patients undergoing surgery for AUS/FLUS were included into the study. Histopathology results were correlated; the impact of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) diagnosis on RoM is evaluated.

RESULTS

Of the 280 patients (16%) undergoing surgery, neoplasia were detected in 177 (RoN:63.2%) and malignancy in 119 (RoM:42.5%) of these neoplasia. Follicular variant of papillary thyroid carcinoma (FVPTC) was the commonest malignancy (55.5%). Additional 58 (20.7%) nodules were neoplastic, of which 26 (9.3%) were encapsulated follicular tumors with unknown malignancy potential (FT-UMP) and 32 (11.4%) were follicular adenomas. The remaining 103 patients (36.8%) had non-neoplastic nodules. After reevaluation of the encapsulated FVPTC cases, 20 of them were NIFTP and RoM dropped to 35.4% with a relative decrease of 16.7% and an absolute decrease of 7.1%.

CONCLUSION

In our series, 42.5% of nodules with AUS/FLUS were malignant; 63.2% of them were neoplastic. The RoM and RoN for AUS/FLUS nodules are still much higher than the revised expected RoM of international guidelines even after NIFTP cases excluded. Therefore, current recommendations should be reevaluated periodically in view of detailed clinicopathologic studies.

Cost effectiveness of intraoperative pathology in the management of indeterminate thyroid nodules

Objective This study aims to determine the cost effectiveness of rapid frozen section (RFS) for indeterminate thyroid nodules. Materials and methods A retrospective chart review was conducted between January 2009 and June 2013 at a tertiary care institution. Main outcomes were number needed to treat, RFS efficacy, and cost-savings of avoiding second completion thyroidectomy. Cost-effectiveness was estimated using 2015 Medicare reimbursement rate. Results Out of 1,114 patients undergoing thyroid surgery, 314 had preoperative AUS/FLUS cytopathology and subsequent thyroid lobectomy with RFS. RFS identified 13 of the 32 patients with malignancy resulting in a total thyroidectomy. 19 of the 29 malignancies not detected by RFS were papillary microcarcinomas. Conclusions Completion thyroidectomy was avoided in 1 out of every 24 patients resulting in cost-savings of $ 80.04 per patient. In the era of outpatient thyroid surgery, intraoperative RFS for indeterminate thyroid nodules is cost-effective.

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features and the risk of malignancy in The Bethesda System for the Reporting of Thyroid Cytopathology

INTRODUCTION

The Bethesda System for the Reporting of Thyroid Cytopathology (TBSRTC) is used to categorize and diagnose thyroid nodules by fine needle aspiration biopsy (FNAB). Each category in TBSRTC is associated with an estimated risk of malignancy (ROM). A subset of noninvasive encapsulated follicular variant of papillary thyroid carcinoma (niEFVPTC) was reclassified as a nonmalignant tumor: noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). We studied the impact of this reclassification on the reported ROM in TBSRTC.

MATERIAL AND METHODS

We searched our institutional files for thyroid FNAB with surgical follow-up. ROM for each TBSRTC category was calculated. Subsequently, cases of niEFVPTC were reviewed and reclassified as NIFTP, if appropriate. ROM for each category was then recalculated after the reclassification.

RESULTS

Twenty-six NIFTP were identified; the corresponding FNABs were distributed among all six TBSRTC categories. The majority of NIFTP FNAB were in the AUS/FLUS and suspicious for malignancy (SUSP) categories, 12 (46.2%) and 8 (30.8%), respectively. While the ROM changed for all diagnostic categories, the greatest change in ROM after reclassification was seen in these two categories. Absolute ROM for AUS/FLUS decreased from 25.0% to 21.0% and SUSP, from 71.7% to 58.3%, changes that were statistically significant.

CONCLUSIONS

The reclassification of niEFVPTC to NIFTP has significantly impacted the ROM in the TBSRTC at our institution. While there was a decrease in ROM for all categories, the greatest reduction to ROM was in the categories of AUS/FLUS and FN. These changes to the ROM should help guide surgical approach moving forward.

Preoperative Diagnostic Categories of Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features in Thyroid Core Needle Biopsy and Its Impact on Risk of Malignancy

This study was designed to evaluate the preoperative diagnostic categories of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) using thyroid core needle biopsy (CNB) and to analyze its impact on the risk of malignancy (ROM). A total of 2687 consecutive thyroid CNBs were reviewed retrospectively and classified into six diagnostic categories using a standardized reporting system similar to the Bethesda System for Reporting Thyroid Cytopathology. Diagnostic categories of CNBs were compared with the final surgical diagnoses, and the ROM in each category was calculated both before and after excluding NIFTP from malignancy. Of 946 surgically resected cases, 683 were diagnosed as papillary thyroid carcinoma (PTC), and 32 (4.7% of PTC) were reclassified as NIFTP. The CNB diagnostic categories of NIFTP were as follows: follicular neoplasm in 20 (62.5%; 14, with nuclear atypia), indeterminate lesion in 11 (34.4%), and suspicious for malignancy in one (3.1%). When combined, NIFTP and encapsulated follicular variant of PTC (EFVPTC) were more often categorized as follicular neoplasm compared with other PTC variants including infiltrative FVPTC. Exclusion of NIFTP from malignant diagnosis led to a significant decrease in the ROM in follicular neoplasm with nuclear atypia category. Thus, thyroid CNB enables to differentiate NIFTP/EFVPTC from other PTCs, providing a useful guide for optimal treatment in patients with these tumors.

Thyroid nodules with Hürthle cells: the malignancy risk in relation to the FNA outcome category

PURPOSE

The aim was to find whether the presence of Hürthle cells (HC) in a smear influences the categorization of FNA results or the risk of malignancy (RoM) of particular categories of cytological diagnosis.

METHODS

25,220 FNA performed in a single center in years 2005-2017 were analyzed. Almost all the examined patients were exposed to moderate iodine deficiency for most of their lives. The distribution of FNA outcome categories was compared between two groups: with or without HC (HC and non-HC). The RoM was evaluated on the basis of postoperative histopathological examination (3082 patients).

RESULTS

HC were found in 7.5% of diagnostic FNA. HC nodules were classified into categories II (78.2% vs. 91.9%, p < 0.0000) and VI (0.4% vs. 1.2%, p = 0.0017) less often than non-HC nodules, but more frequently to categories III (14.4% vs. 5.8%, p < 0.0000), IV (11.2% vs. 0.9%, p < 0.0000) and V (1.5% vs. 0.8%, p = 0.0013). There were no significant differences in RoM between HC and non-HC nodules. The RoM in HC and non-HC nodules of particular categories of the Bethesda system was as follows: II: 1.8% vs. 0.8%, III: 9.7% vs. 3.8% when only the last FNA was considered and 10.8% vs. 6.4% when the category III in any performed FNA was considered; IV: 12.7% vs. 10.9%; V: 41.7% vs. 58.2%; and VI: 100% vs. 96.9%.

CONCLUSIONS

HC nodules are classified into categories of equivocal cytological outcomes more often than nodules without HC. Nevertheless, the presence of HC in a smear does not significantly affect the RoM of FNA categories.

Assessment of The Bethesda System for Reporting Thyroid Cytopathology

OBJECTIVES

Long-term follow-up is important for determining performance characteristics of thyroid fine-needle aspiration (FNA).

METHODS

Histologic or 3 or more years of clinical follow-up was used to calculate performance characteristics of thyroid FNA before and after implementation of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). The impact of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) classification was also investigated.

RESULTS

Follow-up was obtained for 1,277/1,134 and 1,616/1,393 aspirates/patients (median clinical follow-up, 9.9 and 4.4 years, pre- and post-TBSRTC, respectively). Nondiagnostic, suspicious for follicular neoplasm, and suspicious for malignancy (SFM) diagnoses decreased and benign diagnoses increased post-TBSRTC, while atypical rate remained less than 1%. Negative predictive value for benign nodules and positive predictive value (PPV) for SFM increased significantly. Eleven nodules were reclassified as NIFTP, slightly decreasing PPV/risk of malignancy (ROM).

CONCLUSIONS

Appropriate ROM for thyroid FNA can be achieved through application of TBSRTC terminology with minimal use of atypical category.

What is the Appropriate Nodular Diameter in Thyroid Cancer for Extraction by Transoral Endoscopic Thyroidectomy Vestibular Approach Without Breaking the Specimens? A Surgicopathologic Study

Transoral Endoscopic Thyroidectomy Vestibular Approach (TOETVA) is a novel technique with better cosmetic results. However, extraction of a large malignant thyroid nodule from the central incision of TOETVA necessitates breaking it into pieces to avoid mental nerve injury, a situation that may violate a proper oncological surgery. In this study, we sought the appropriate nodular diameter in thyroid cancer to be removed in an intact status through the central incision of the TOETVA technique. A total of 27 cases of thyroid nodules were operated using the TOETVA technique from Aug 2016 to July 2017. Excluding 10 benign goiters, the specimens of 17 thyroid cancer cases were divided into intact (group T, n=7) and fragmented (group F, n=10), with a median nodular diameter of 18.35 and 30.30 mm, respectively. Receiver operating characteristic (ROC) curve analysis revealed that the safest nodular diameter is 20 mm, with 100% sensitivity and 87.5% specificity.

Malignancy rate of atypia of undetermined significance/follicular lesion of undetermined significance in thyroid nodules undergoing FNA in a suburban endocrinology practice: A retrospective cohort analysis

BACKGROUND

The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) was created to establish a standard terminology regarding thyroid nodules that can be shared between endocrinologists, pathologists, radiologists, and surgeons. Since its inception and use in 2009, multiple large hospitals and academic institutions have performed retrospective studies to compare their classification rates, specifically those of atypia of undetermined significance (AUS) and follicular lesion of undetermined significance (FLUS), with the recommended rates created by the National Cancer Institute. The current study compared AUS/FLUS rates at a private suburban endocrine practice with those of previous publications from large institutions and the rates established by the National Cancer Institute.

METHODS

Charts from 893 patients with fine-needle aspiration (FNA) performed in 2015 were reviewed. Data specific to thyroid aspirates classified as AUS/FLUS were organized into whether patients underwent surgery, underwent subsequent repeat FNA, or required continued observation. These results then were calculated to reveal the rate of malignancy in the AUS/FLUS category with surgical pathology in the study institution.

RESULTS

A total of 893 patients underwent FNA, with 43 patients (4.82%) shown to have AUS/FLUS. A total of 21 patients proceeded to undergo thyroidectomy or lobectomy, with 7 patients (33.3%) found to have papillary or follicular thyroid carcinoma.

CONCLUSIONS

The rate of use of the AUS/FLUS category for thyroid nodules examined at the study institution was found to be within the recommended range set forth by TBSRTC. However, the malignancy rates on histopathology in the study institution were found to be higher than the new proposed malignancy rates from TBSRTC published in 2017. This finding is comparable to those of multiple other community and academic institutions performed prior to and after institution of the new guidelines.

Does the ACR TI-RADS scoring allow us to safely avoid unnecessary thyroid biopsy? single center analysis in a large cohort

INTRODUCTION

The American College of Radiology (ACR) has recently proposed a guideline that recommends clinicians to perform thyroid fine-needle aspiration biopsy (FNAB) on the basis of ultrasound features. In this study, we focused on nodules for which no biopsy is recommended by the ACR Thyroid Imaging, Reporting and Data System (TI-RADS) guideline.

SUBJECTS AND METHODS

Two-thousand eight-hundred and forty-seven consecutive patients with thyroid nodules who underwent FNAB according to the 2009 American Thyroid Association (ATA) guideline were included. The nodules were re-classified according to the ACR TI-RADS guideline as benign (TR1), not suspicious (TR2), mildly suspicious (TR3), moderately suspicious (TR4) and highly suspicious (TR5). The TR3 category was stratified into two subcategories as regard to the nodule size (TR3; <25 mm and TR3; ≥25 mm).

RESULTS

Two-hundred and thirty-three (8.2%) patients with non-diagnostic FNABs were excluded. When the TR2 and TR3; <25 mm categories were merged, FNAB was suggestive of thyroid cancer in 17 of 1382 patients (1.2%). FNAB revealed Bethesda IV-VI in 5 of 273 patients with the TR3; ≥25 mm category (1.8%), in 61 of 896 patients with the TR4 category (6.8%), and in 18 of 63 of patients with the TR5 category (28.6%). The ACR TI-RADS scoring was 98.8% (95% CI: 98 to 99.3) specific for identification of a benign nodule.

CONCLUSION

Our data suggest that ACR TI-RADS scoring is an applicable and potentially cost-effective approach to determine thyroid nodules to be biopsied, although a small proportion of thyroid cancers would be missed.

Morphology combined with ancillary techniques: An algorithm approach for thyroid nodules

INTRODUCTION

Several authors have underlined the limits of morphological analysis mostly in the diagnosis of follicular neoplasms (FN). The application of ancillary techniques, including immunocytochemistry (ICC) and molecular testing, contributes to a better definition of the risk of malignancy (ROM) and management of FN. According to literature, the application of models, including the evaluation of ICC, somatic mutations (ie, BRAF^V600E ), micro RNA analysis is proposed for FNs. This study discusses the validation of a diagnostic algorithm in FN with a special focus on the role of morphology then followed by ancillary techniques.

METHODS

From June 2014 to January 2016, we enrolled 37 FNs with histological follow-up. In the same reference period, 20 benign nodules and 20 positive for malignancy were selected as control. ICC, BRAF^V600E mutation and miR-375 were carried out on LBC.

RESULTS

The 37 FNs included 14 atypia of undetermined significance/follicular lesion of undetermined significance and 23 FN. Specifically, atypia of undetermined significance/follicular lesion of undetermined significance resulted in three goitres, 10 follicular adenomas and one NIFTP whereas FN/suspicious for FN by seven follicular adenomas and 16 malignancies (nine non-invasive follicular thyroid neoplasms with papillary-like nuclear features, two invasive follicular variant of papillary thyroid carcinoma [PTC] and five PTC). The 20 positive for malignancy samples included two invasive follicular variant of PTC, 16 PTCs and two medullary carcinomas. The morphological features of BRAF^V600E mutation (nuclear features of PTC and moderate/abundant eosinophilic cytoplasms) were associated with 100% ROM. In the wild type cases, ROM was 83.3% in presence of a concordant positive ICC panel whilst significantly lower (10.5%) in a negative concordant ICC. High expression values of MirR-375 provided 100% ROM.

CONCLUSIONS

The adoption of an algorithm might represent the best choice for the correct diagnosis of FNs. The morphological detection of BRAF^V600E represents the first step for the identification of malignant FNs. A significant reduction of unnecessary thyroidectomies is the goal of this application.

Classification of thyroid fine-needle aspiration cytology into Bethesda categories: An institutional experience and review of the literature

Background:

Fine-needle aspiration cytology (FNAC) of thyroid is the initial screening test for thyroid nodules. The Bethesda system classifies thyroid FNAC into six categories. Each category is linked to a malignancy risk and has a recommended clinical management. The aim of this study is to analyze the thyroid cytology smears by Bethesda system and to correlate the diagnosis of cytopathology with histopathology, whenever surgery was done.

Materials and Methods:

This study presents our experience with the Bethesda system in 681 thyroid FNAs from 632 patients in the period between January 2013 and December 2016.

Results:

Categories were as follows: 10.1% were Category I (nondiagnostic), 68.8% Category II (benign), 12.4% were Category III (atypia of undetermined significance), 2.9% were Category IV (suspicious for follicular neoplasm), 2.6% were Category V (suspicious for malignancy), and 4.1% were Category VI (malignant). Surgery was done on 126 nodules from 119 patients with an overall rate of malignancy of 27.8% (35/126 nodules).

Conclusion:

The Bethesda System for Reporting Thyroid Cytopathology proved to be an excellent reporting system.

Differential Growth Rates of Benign vs. Malignant Thyroid Nodules

CONTEXT

Thyroid nodule growth was once considered concerning for malignancy, but data showing that benign nodules grow questioned the use of this paradigm. To date, however, no studies have adequately evaluated whether growth rates differ in malignant vs. benign nodules.

OBJECTIVE

To sonographically evaluate growth rates in benign and malignant thyroid nodules ≥1 cm.

DESIGN

Prospective, cohort study of patients with tissue diagnosis of benign or malignant disease, with repeated ultrasound evaluation six or more months apart.

MAIN OUTCOMES

Growth rate in largest dimension of malignant compared with benign thyroid nodules. Regression models were used to evaluate predictors of growth.

RESULTS

Malignant nodules (126) met inclusion criteria (≥6-month nonoperative followup) and were compared with 1363 benign nodules. Malignant nodules were not found to be uniquely selected or prospectively observed solely for low-risk phenotype. Median ultrasound intervals were similar (21.8 months for benign nodules; 20.9 months for malignant nodules). Malignant nodules were more likely to grow >2 mm/y compared with benign nodules [relative risk (RR) = 2.5, 95% confidence interval (CI), 1.6 to 3.1; P < 0.001], which remained true after adjustment for clinical factors. The RR of a nodule being malignant increased with faster growth rates. Malignant nodules growing >2 mm/y had greater odds of being more aggressive cancers [intermediate risk: odds ratio (OR) = 2.99; 95% CI, 1.20 to 7.47; P = 0.03; higher risk: OR = 8.69; 95% CI, 1.78 to 42.34; P = 0.02].

CONCLUSIONS

Malignant nodules, especially higher-risk phenotypes, grow faster than benign nodules. As growth >2 mm/y predicts malignant compared with benign disease, this clinical parameter can contribute to the assessment of thyroid cancer risk.

Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features Accounts for More Than Half of "Carcinomas" Harboring RAS Mutations

BACKGROUND

Molecular testing of thyroid nodules is increasingly being utilized to guide clinical management decisions. RAS mutations are the most frequent mutations detected in the context of an indeterminate fine-needle aspiration (FNA) diagnosis. The term "noninvasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP) was recently introduced to promote conservative management of tumors previously classified as noninvasive follicular variant of papillary thyroid carcinoma (FVPTC). This change in terminology was based on the indolent clinical behavior of these tumors and their molecular profile, which includes frequent RAS mutations. The aim of this study was to determine the percentage of RAS-mutant "carcinomas" that would now be classified as NIFTPs.

METHODS

A search was performed for cases with known activating RAS mutations in a database of 199 thyroid carcinomas that underwent molecular characterization as part of Profile:Oncopanel between July 2013 and July 2015. Cases of FVPTC were re-reviewed to identify tumors that now would be categorized as NIFTP. Preceding FNA diagnoses were recorded, and cases with an indeterminate FNA result (defined as a diagnosis of atypia/follicular lesion of undetermined significance, suspicious for follicular neoplasm, or suspicious for malignancy) were identified.

RESULTS

A total of 27 RAS-mutant thyroid tumors were identified. Fifteen (56%) cases had an NRAS mutation, nine (33%) had an HRAS mutation, and three (11%) had a KRAS mutation. Twenty-four (89%) cases had a preceding FNA, 19 (79%) of which had an indeterminate FNA diagnosis. The surgical resection specimen demonstrated FVPTC in 20 (74%) cases, classical type PTC in two (7%), solid variant of PTC in one (4%), and follicular thyroid carcinoma in four (15%). Of the 20 FVPTCs, 16 (80%) would now be classified as NIFTP. NIFTPs accounted for 59% of RAS-mutant carcinomas overall and 63% of RAS-mutant carcinomas with a prior indeterminate FNA diagnosis.

CONCLUSION

NIFTPs accounted for more than half of RAS-mutant "carcinomas" in this cohort. In cases where clinical and sonographic data support a low-risk phenotype, these results suggest that a lobectomy should be considered as the initial surgical approach for a nodule with an indeterminate FNA diagnosis and a RAS mutation.

Bethesda Category III, IV, and V Thyroid Nodules: Can Nodule Size Help Predict Malignancy?

BACKGROUND

The association of tumor size with malignancy in thyroid nodules with indeterminate cytology (atypia of undetermined significance [AUS]/follicular lesion of undetermined significance [FLUS], suspicious for follicular neoplasm [SFN]/Hürthle cell neoplasm [HCN], and suspicious for malignancy [SM]) has not been clearly studied.

STUDY DESIGN

We retrospectively identified 1,104, patients who underwent thyroid FNA and subsequent thyroidectomy. Patients with indeterminate cytology were reviewed. The size of the nodule was determined by ultrasound. Malignancy was confirmed by final histology. Logistic regression modeling was performed to determine if nodule size was associated with malignancy.

RESULTS

There were 461 (42%) patients who had indeterminate cytology by FNA. The median nodule size of all indeterminate lesions was 2.1 cm (range 0.5 to 10 cm). The median nodule size for AUS/FLUS was 2.1 cm (range 0.7 to 8 cm), for SFN was 2.4 cm (range 0.5 to 10 cm), for HCN was 2.2 cm (range 0.5 to 9.3 cm), and for SM was 1.6 cm (range 0.5 to 6 cm). On final histology, 121 (28%) index lesions were malignant (AUS 23%; FLUS 14%; SFN 22%; HCN 25%; SM 69%). On logistic regression, nodule size was not associated with increased odds of malignancy in all lesions with indeterminate cytology (odds ratio [OR] 0.83; 95% CI 0.76 to 1.00; p = 0.051). Nodule size was not associated with malignancy in the index nodule of AUS/FLUS, SFN, or SM lesions. Increased nodule size was associated with malignancy in HCN lesions (OR 2.17; 95% CI 1.16 to 4.04; p = 0.01).

CONCLUSIONS

The findings of this study suggest that larger HCN nodules are more likely to be malignant. Nodule size alone was not predictive of malignancy in patients with AUS/FLUS, SFN, or SM. Clinical picture, institution-specific malignancy rates, and molecular testing continue to be important factors guiding treatment.

The role of miRNAs in the evaluation of follicular thyroid neoplasms: an overview of literature

MicroRNA (miRNA) deregulation has been frequently associated with different human cancers. Not only have miRNAs been involved in almost every cellular function but they have also been linked with a significant number of cancers including thyroid carcinomas. Specifically, thyroid tumors encompass several different miRNA profiles based on the histotypes. Furthermore, thyroid lesions with their broad spectrum of neoplasms (from benign to malignant entities) offer the possibility of studying and recognizing specific subsets of different up-and downregulated miRNAs in each different entity. To date, the majority of authors completed their evaluation mostly by including histologic samples of thyroid tumors. Nonetheless, in the last years, a few studies are focusing on the role of miRNA expression in thyroid fine-needle aspiration cytology (FNAC) regardless of the cytologic preparation, including liquid-based cytology. This growing interest is driven by the possible role of miRNAs in the malignant risk stratification, especially for the indeterminate categories of follicular neoplasms (FNs). In this review we overview the reliability of analyzing miRNAs on thyroid lesions, including those diagnosed as FNs, to identify whether their profiles are likely to distinguish benign from malignant lesions, providing a predictive molecular diagnosis on FNAC.

The evaluation of miRNAs on thyroid FNAC: the promising role of miR-375 in follicular neoplasms

Fine needle aspiration cytology (FNAC) plays an essential role in the evaluation of thyroid nodules especially for the category of follicular neoplasms (FN) representing 25 % of all thyroid cases including different neoplastic entities. Hence, one of the most promising areas is the application of molecular tests to FNAC. Among them, microRNAs (miRNA),identified as negative (post-transcriptional) gene expression regulators involved in tumor development, are likely to discriminate among FNs. Limited data explored the use of miRNAs on FNAC as well as their role in the malignant risk stratification. We aimed to define whether liquid-based cytology (LBC) is a valid method for miRNA evaluation. From June 2014 to March 2015, we enrolled 27FNs with histological follow-up. In the same reference period, 13 benign nodules (BN) and 20 positive for malignancy (PM) were selected as controls. Histologically, FNs resulted in 14 malignancies (3 papillary thyroid carcinoma-PTC and 11 follicular variant of PTC-FVPC) and 13 follicular adenomas (FA). The 20 PMs included two FVPC, 16 PTC and two medullary thyroid carcinoma (MTC). Five miRNAs (10b, 92a, 221/222 cluster, and 375) were studied on LBC and quantified by real-time PCR. Only miR-375 was over-expressed in the FNs diagnosed as carcinomas and in the PMs. A cut-off of 12 miR-375/U6 relative ratio recognized all BNs and 95 % PMs. Specifically, in each category, FVPCs and PTCs did not show any difference while MTCs had the highest value. miR-375 shows 97.1 % sensitivity, 100 % specificity, 96.3 % negative predictive value (NPV), 100 % positive predictive value (PPV), and 98.3 % diagnostic accuracy. LBC is suitable for miRNAs evaluation. miR-375 resulted over-expressed in all malignant FNs and 95 % PMs. It may represent a valid aid in ruling out BNs and supporting PTCs and/or FVPCs.

Proteomic analysis of fine-needle aspiration in differential diagnosis of thyroid nodules

Thyroid nodules are common in the general population and vary widely in their propensity to harbor thyroid malignancies. The category of follicular lesion of undetermined significance, for instance, carries only a 15% risk of malignancy. The overarching aim of this work was the proteomic study of thyroid cancer because more effort needs to be placed on differentiating malignant thyroid nodules to avoid unnecessary thyroidectomy. We used 2-dimensional electrophoresis coupled to nano-liquid chromatography electrospray ionization tandem mass spectrometry, to examine fine-needle aspiration (FNA), which was easily attainable from the wash of the syringe used for classical FNA biopsy. Overall, we found 25 different proteins able to discriminate benign from malignant samples. The different expression of moesin; annexin A1 (ANXA1); cornulin (CRNN); lactate dehydrogenase; enolase; protein DJ-1; and superoxide dismutase was confirmed in FNA by enzyme-linked immunosorbent assay or Western blot. Receiver operating characteristic curves were calculated to investigate the discriminative power of our marker. The best performance in diagnosis was obtained by combining ANXA1, enolase, protein DJ-1, superoxide dismutase, and CRNN. In addition, the most highly ranked proteins, from the perspective of follicular lesion of undetermined significance, were ANXA1 and CRNN. The research of these candidate biomarkers has then been widened to other biological fluids, such as serum and whole saliva. In conclusion, we believe that when a decision by a thyroid nodule biopsy cannot be distinctly made, the combination of our biomarkers may be one of the criteria to be taken into account for the final decision, together with the identification of ANXA1 in serum and saliva.

Stromal tissue as an adjunct tool in the diagnosis of follicular thyroid lesions by fine-needle aspiration biopsy

Background:

The stroma in fine-needle aspiration biopsy (FNAB) of thyroid lesions has not been well investigated.

Design:

We studied 256 consecutive cases of thyroid FNAB prepared with traditional smear technique. The stroma was categorized: Type 1a consisted of long (more than 3 mm), broad bands composed of mesh containing collagen fibrils thickened by entrapped blood components and follicular cells. Type 1b consisted of dense strands/bands. Type 2 was similar to Type 1a but with shorter (<2 mm) and looser stromal strands.

Results:

Types 1a and b showed straight/curved/circular branching patterns suggestive of incomplete frameworks of nodular/papillary architectures or fragments of capsule. Type 1b stroma likely represented thick/collagenized fibrous septae. Incomplete or complete rings of small encapsulated tumor were occasionally identified. These frameworks of stroma were frequently associated with multinodular goiters (MNGs) which are often hypocellular and follicular neoplasms/papillary thyroid carcinoma with increased cellularity. Type 2 was associated with microfollicles in encapsulated neoplasms or with macrofollicles in MNG. Follicular lesions of unknown significance (n = 41) either negative (n = 26) or positive (n = 15) for carcinoma in subsequent follow-up were frequently associated with stroma characteristic of MNG and carcinoma, respectively.

Conclusion:

The preservation of the in vivo architecture of Type 1 is likely due to its elasticity. Recognition of the stromal architecture will likely facilitate the diagnosis.

The 5-tiered categorization system for reporting cytology is sufficient for management of patients with thyroid nodules compared to the 6-tiered Bethesda system

To analyze whether the 5-tiered categorization system without the atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS) category is sufficient compared to the 6-tiered Bethesda system. This IRB-approved retrospective study was waived informed consent. The pre-Bethesda period was from March 2008 to December 2008 and the Bethesda period was from January 2012 to January 2013. Of 4677 nodules ≥10 mm with initial ultrasonography-guided fine-needle aspiration, 2553 nodules were from the pre-Bethesda period and 1754 nodules were from the Bethesda period. The utilization and malignancy rates of each category were compared between the two periods. The utilization rate of the benign category decreased from 67.7 % in the pre-Bethesda period to 60.0 % in the Bethesda period (p = 0.001). In the pre-Bethesda period, the malignancy rates of the non-diagnostic, benign, suspicious follicular neoplasm/Hürthle cell neoplasm, suspicious for malignancy, and malignancy categories were 3.8, 1.9, 25, 78.8, and 99.7 %, respectively. The malignancy rate of the benign category decreased from 1.9 to 0.3 % after the Bethesda system (p < 0.001). The utilization and malignancy rates of the AUS/FLUS category were 7 and 22.8 %. When the AUS/FLUS category was included in the benign category, the malignancy rate became 2.6 % which was not significantly different from 1.9 % in the pre-Bethesda period (p = 0.189). The malignancy rates of other categories were not significantly different. The 5-tiered categorization system without the AUS/FLUS category for reporting cytology was sufficient for management of patients with thyroid nodules compared to the 6-tiered categorization of the Bethesda system.

Noninvasive Follicular Variant of Papillary Thyroid Carcinoma and the Afirma Gene-Expression Classifier

BACKGROUND

It is now recognized that noninvasive follicular variant of papillary thyroid carcinoma (NFVPTC) is a distinct subset of FVPTC with an exceedingly indolent clinical course. The Afirma gene-expression classifier (GEC) helps guide clinicians in the management of thyroid nodules with indeterminate fine-needle aspiration (FNA) results. Thyroid surgery is recommended for nodules with a suspicious Afirma result, whereas observation is deemed reasonable for most nodules with a benign result. The aim of this study was to confirm that the Afirma test detects NFVPTCs and to determine how many carcinomas detected by the Afirma GEC represent NFVPTCs.

METHODS

From a database of 249 FNAs sent for Afirma testing between January 2012 and October 2014, a search was conducted for cases with a preceding FNA diagnosis of atypia/follicular lesion of undetermined significance (AUS/FLUS) or suspicious for a follicular neoplasm (SFN), a suspicious Afirma result, and a corresponding resection specimen reviewed at Brigham and Women's Hospital. The diagnoses of the prior FNAs and subsequent resection specimens were recorded. Slides for all resection specimens with a diagnosis of FVPTC were reviewed to identify NFVPTCs.

RESULTS

Sixty-three cases met the inclusion criteria. The preceding FNA diagnosis was AUS/FLUS in 34 (54%) cases and SFN in 29 (46%) cases. The surgical resection specimen demonstrated 16 (25%) FVPTCs, five (8%) follicular thyroid carcinomas, one (2%) classical type PTC, and 41 (65%) benign tumors/nodules. Of the 16 FVPTCs, 14 (88%) were NFVPTCs. Thus, NFVPTCs accounted for 64% of the carcinomas in the cohort.

CONCLUSION

These results indicate that the Afirma GEC detects NFVPTCs and that many of the carcinomas detected by Afirma are NFVPTCs. While all care should be individualized and include clinical and sonographic assessment, these results suggest lobectomy as opposed to total thyroidectomy should be considered for nodules with a preceding AUS/FLUS or SFN on cytology and a suspicious Afirma result.

Fine needle aspiration biopsy of thyroid nodules: cytologic and histopathologic correlation of 1096 patients

Via routinely used thyroid function tests, scintigraphy and ultrasonography (USG), important information is obtained in the clinical and diagnostic practice for thyroid nodules. However, the distinction between benign and malignant lesions cannot precisely be performed with these tests. Thyroid fine needle aspiration biopsy (FNAB) is considered the most reliable diagnostic method in the differentiation between benign and malignant thyroid nodules. It has recently been likely to perform aspiration from deeper nodules via the implemention of FNAB along with USG. Today, in cytopathological examination of thyroid FNAB, standardized Bethesda System for Reporting Thyroid Cytopathology (BSRTC) system is used. Here, FNAB was performed in 1096 patients with thyroid nodules in the Medical School of Selcuk University between January 2009 and July 2014. Patients consisted of 919 women and 177 men between 12 and 87 years of age. Evaluated via BSRTC, the results were classified as unsatisfactory, benign, atypia (or follicular lesions) of undetermined significance (AUS), follicular neoplasm or lesions suspicious for follicular neoplasm (FN), suspected malignant and malignant. After FNAB, 183 patients were operated and evaluated histopathologically. Histological malignancy rates of the categories were as follows: 16% (5), 15% (6) 14% (1) 60% (9), 72% (18) and 97% (63), respectively. In our study, we aimed to compare FNAB results of thyroid nodules with histopathology results after thyroidectomy and to show the sensitivity and specificity of FNAB technique to be higher in the follow-up and diagnosis of thyroid lesions. Given the malignancy detection rate in the follow-up of patients whose cytology was reported as inadequate, we also consider follow-ups are important in these patients.

Effect of malignancy rates on cost-effectiveness of routine gene expression classifier testing for indeterminate thyroid nodules

BACKGROUND

The value of gene expression classifier (GEC) testing for cytologically indeterminate thyroid nodules lies in its negative predictive value, which is influenced by the prevalence of malignancy. We incorporated actual GEC test performance data from a tertiary referral center into a cost-effectiveness analysis of GEC testing.

METHODS

We evaluated consecutive patients who underwent GEC testing for Bethesda category III and IV nodules from 2012 to 2014. Routine GEC testing was compared with conventional management by the use of a decision tree model. Additional model variables were determined via literature review. A cost-effectiveness threshold of $100,000 per quality-adjusted life-year (QALY) was used.

RESULTS

The prevalence of malignancy was 24.3% (52/214). Sensitivity and specificity of GEC testing were 96% and 60%. Conventional management cost $11,119 and yielded 22.15 QALYs. Routine GEC testing was more effective and more costly, with an incremental cost-effectiveness ratio of $119,700/QALY, making it not cost-effective. At malignancy rates of 15, 25, or 35%, routine GEC testing became cost-effective when the cost of GEC testing fell below $3,167, $2,595, or $2,023.

CONCLUSION

The cost-effectiveness of routine GEC testing varies inversely with the underlying prevalence of malignancy in the tested population. The value of routine GEC testing should be assessed within the context of institution-specific malignancy rates.

The diagnosis value of acoustic radiation force impulse (ARFI) elastography for thyroid malignancy without highly suspicious features on conventional ultrasound

OBJECTIVE

The aim of this study was to evaluate the potential diagnostic performance of acoustic radiation force impulse (ARFI) elastography in identifying malignancy in nodules that do not appear highly suspicious on conventional ultrasound (US).

METHODS

330 pathologically confirmed thyroid nodules (40 malignant and 290 benign; mean size, 22.0±11.6 mm) not suspicious of malignancy on conventional US in 330 patients (mean age 52.8±11.7 years) underwent ARFI elastography before surgery. ARFI elastography included qualitative ARFI-induced strain elastography (SE) and quantitative point shear wave elastography (p-SWE). ARFI-induced SE image was assessed by SE score, while p-SWE was denoted with shear wave velocity (SWV, m/s). The diagnostic performance of four criteria sets was evaluated: criteria set 1 (ARFI-induced SE), criteria set 2 (p-SWE), criteria set 3 (either set 1 or 2), criteria set 4 (both set 1 and 2). Receiver operating characteristic curve (ROC) analyses were performed to assess the diagnostic performance.

RESULTS

SE score ≥4 was more frequently found in malignant nodules (32/40) than in benign nodules (30/290, P<0.001). The mean SWV of malignant nodules (3.64±2.23 m/s) was significantly higher than that of benign nodules (2.02±0.69 m/s) (P<0.001). ARFI-induced SE (set 1) had a sensitivity of 80.0% (32/40) and a specificity of 89.7% (260/290) with a cut-off point of SE score ≥4; p-SWE (set 2) had a sensitivity of 80.0% (32/40) and a specificity of 57.9% (168/290) with a cut-off point of SWV ≥2.15 m/s. When ARFI-induced SE and p-SWE were combined, set 3 had the highest sensitivity (92.5%, 37/40) while set 4 had the highest specificity (95.2%, 276/290).

CONCLUSION

ARFI elastography can be used for differential diagnosis of malignant thyroid nodules without highly suspicious features on US. The combination of ARFI-induced SE and p-SWE leads to improved sensitivity and specificity.

Institution-specific risk of papillary thyroid carcinoma in atypia/follicular lesion of undetermined significance

BACKGROUND

The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) is used in surgical decision-making according to malignancy risk in each category. Malignancy risk in atypia/follicular lesion of undetermined significance (AUS/FLUS) is estimated in BSRTC to be 5% to 15%, but institutional data have varied widely.

METHODS

We conducted a post-BSRTC 4-year retrospective analysis of index thyroid nodule cytology and histopathology in an academic head and neck endocrine surgery setting.

RESULTS

Of 2939 thyroid cytology reports from 1944 patients, the most advanced BSRTC category was AUS/FLUS in 233 patients (12.0%) of which 187 went to thyroidectomy. In AUS/FLUS, the upper and lower boundary estimates of the malignancy rate were 46% and 37%, accordingly. The malignancy rate did not vary significantly by cytopathologist or cytopathologic features.

CONCLUSION

Malignancy rates in AUS/FLUS vary by institution from 6% to 46%. Given the subjective nature of thyroid cytopathology and interpretation of the BSRTC categories, guidelines should encourage the use of institution-specific data on malignancy risk in treatment decisions. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1210-E1215, 2016.

Thyroid Nodules: Nondiagnostic Cytologic Results according to Thyroid Imaging Reporting and Data System before and after Application of the Bethesda System

PURPOSE

To compare the malignancy rates and the effectiveness of the Thyroid Imaging Reporting and Data System (TIRADS) for risk stratification of nodules with nondiagnostic results classified before and after application of the Bethesda System for Reporting Thyroid Cytopathology.

MATERIALS AND METHODS

This retrospective study was approved by an institutional review board, with waiver of informed consent. A total of 763 patients with 790 thyroid nodules and nondiagnostic cytologic results were included (mean age ± standard deviation, 52.3 years ± 11.5), 485 nodules from the pre-Bethesda period (from March 2007 to December 2008) and 305 nodules from the post-Bethesda period (from May 2011 to May 2012). A TIRADS category was assigned to each thyroid nodule on the basis of the number of features that appeared suspicious for cancer at ultrasonography (US). Malignancy rates and TIRADS categories during the two periods were compared. Correlation between TIRADS category and malignancy risk between the two periods was evaluated and compared.

RESULTS

The malignancy rates of nodules with nondiagnostic cytologic results were not significantly different between the two periods (P = .148). Malignancy risk of TIRADS category 3, 4a, 4b, 4c, and 5 was 1.8%, 5.7%, 4.1%, 29.8%, and 16.7%, for the pre-Bethesda period, and 1.6%, 3.0%, 7.1%, 16.3%, and 25.0% for the post-Bethesda period, respectively. Near-perfect correlation was seen between the TIRADS category and malignancy risk in the post-Bethesda period (r = 0.961, P = .009), while no significant correlation was found in the pre-Bethesda period (r = 0.731, P = .161).

CONCLUSION

Malignancy risk stratification with TIRADS was more effective for nodules with nondiagnostic cytologic results classified according to the Bethesda System. When these Bethesda-classified nodules with nondiagnostic results are evaluated as TIRADS category 3 or 4a, they may be treated conservatively with follow-up US, but when other cytologic classifications are applied, follow-up US and fine- needle aspiration must be considered for nodules showing one or more features suspicious for cancer at US.

Prospective evaluation of impact of using the Bethesda System for Reporting Thyroid Cytopathology: an institutional experience

INTRODUCTION

The Bethesda System for Reporting Thyroid Cytology (BSRTC) refines the definition of and provides specific diagnostic criteria for fine-needle aspiration (FNA) assessment of thyroid lesions. This study was conducted to prospectively evaluate the diagnostic and clinical impact of using BSRTC for management of thyroid lesions and to compare diagnostic performance of post-BSRTC period with that of pre-BSRTC period.

MATERIALS AND METHODS

The study included FNA specimens obtained in our institution 2.5 years prior to and 2.5 years after implementing BSRTC. Nondiagnostic rate, distribution of the diagnostic categories, rate of surgical follow-up, cytohistologic concordant rate, and risk of malignancy were calculated and compared between pre- and post-BSRTC periods.

RESULTS

In comparison to the pre-BSRTC period, the post-BSRTC period generated a lower nondiagnostic rate (19.9% versus 15.8%), a greater proportion of benign (65.3% versus 69.2%) and atypia of undetermined significance or follicular lesion of undetermined significance (4.4% versus 7.4%) in contrast with a decreased proportion of follicular neoplasm or suspicious for follicular neoplasm categories (5.6% versus 2.2%). Rate of surgical follow-up decreased for benign (13.8% versus 7.6%) and atypia of undetermined significance or follicular lesion of undetermined significance (61.5% versus 42.1%) categories, and overall surgical rate reduced (24.2% versus 18.1%). Implementation of BSRTC did not affect overall rate of cytohistologic concordance (78.4% versus 80.5%) or the overall rate of histologically proven malignancy (30.6 versus 36.9%), whereas the individual cytohistologic concordant rate and the malignant rate for each of the diagnostic categories did not differ between pre- and post-BSRTC.

CONCLUSIONS

The implementation of BSRTC resulted in a decreased overall surgical rate, particularly for benign and follicular lesion of undetermined significance categories, without affecting overall cytohistologic concordance and rate of malignancy.

Diagnostic accuracy of Bethesda system for reporting thyroid cytopathology: an institutional perspective

Introduction

Thyroid swelling is common problem among South Asian women. Although benign nodules far outnumber cancerous lesions, the risk of malignancy needs to be evaluated preoperatively for which fine needle aspiration cytology (FNAC) is widely used. Bethesda system for reporting thyroid cytopathology (BSRTC) was introduced to streamline the reporting of thyroid aspirates. We aimed to evaluate the disease spectrum of thyroid cytopathology and correlation of BSRTC with final histopathology in our setup.

Methods

The study was conducted at Histopathology department of Liaquat National Hospital, Karachi, involving 528 patients with thyroid swelling who underwent FNAC. Out of these 528 cases, 61 patients subsequently underwent surgical excision. Results of final histopathology were correlated with cytologic diagnosis.

Results

Mean age of the patients included in the study was 39.7 ± 13(14–84) and male to female ratio was 1:3.6. Out of total 528 cases, 403 cases were diagnosed as benign (Bethesda 2) and 67 were Bethesda 3 (follicular lesion of undetermined significance, FLUS) while 22 cases were categorized as either malignant or suspicious for malignancy (Bethesda 6 and 5). Histopathologic correlation was done in 61 cases. For Bethesda 5 and 6 categories, 100% concordance was found, however for Bethesda 2 category, 5 out of 45 cases were found to have malignant diagnosis on final histopathology. The incidence of malignancy in Bethesda categories 2 through 4 were 11.1%, 33.4%, 25%, 100% and 100% respectively. Overall accuracy of FNA cytology was 80.3% with 64.3% sensitivity and 85.1% specificity.

Conclusion

Our study validated the accuracy of BSRTC in our setup. Therefore we recommend routine use of BSRTC for reporting thyroid cytopathology for initial workup of patients with thyroid nodule. However, risk of malignancy was found to be significantly high in Bethesda 3 category to warrant further workup including ultrasound/thyroid scan in addition to repeat FNAC.