The Bethesda System for Reporting Thyroid Cytopathology in the African American population: A tertiary centre experience.

BACKGROUND: The reported risk of malignancies (ROM) remains controversial for fine needle aspiration (FNA) of thyroid nodules in the African American (AA) population. Herein, the ROM along with frequency was assessed for each of the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) diagnostic categories. MATERIALS AND METHODS: The electronic pathology archive of a large academic hospital was retrospectively searched for cytopathology reports of thyroid nodules in AA patients (2010-2019) and Non-African American (NAA) control cases. The patients' demographic, thyroid nodule characteristics, FNA results using TBSRTC and surgical diagnoses were recorded, whenever available. RESULTS: Three hundred ninety-one cases were identified, 317 females (81.1%) and 74 males (18.9%) with median age 50.0 (SD = 14.4). The mean size of the nodules was 2.1 cm (SD = 1.4). The Bethesda categories were: 5.4% (I), 35.0% (II), 35.3% (III), 7.7% (IV), 3.3% (V) and 13.3% (VI). The overall ROM of thyroid nodules was 43.8% (89/203) on surgical follow-up (203/391). The ROM in each Bethesda categories were: 33.3% (I), 11.6% (II), 35.2% (III), 15.8% (IV), 83.3% (V) and 100% (VI) on surgical follow-up. The frequency of thyroid nodules was higher in AA females; however, the ROM was higher in AA males (48.3%) compared with AA females (41.2%). CONCLUSION: The ROM in Categories I, II and III was higher than those reported in the TBSRTC while being similar in Categories IV, V and VI. The overall risk of thyroid malignancy in our AA patient population was higher than those in the literature. The overall ROM of thyroid nodules in AA males was higher than of AA females.

Results of retrospective classification of thyroid FNAs according to the Bethesda system: would this have improved accuracy?

OBJECTIVES: To retrospectively reclassify the results of fine needle aspiration (FNA) cytology at our institution according to the Bethesda system for reporting thyroid cytopathology (TBSRTC), and to determine whether the introduction of the new classification system would have influenced the diagnostic accuracy compared with our existing system in which suspicious/indeterminate categories (categories III-IV) are managed according to clinical findings and cytopathologists' recommendations. METHODS: FNAs performed under ultrasound guidance between 2001 and 2012, and subsequently verified by histology or repeat FNA and follow-up, were reviewed and retrospectively reclassified according to TBSRTC. RESULTS: Among a total of 1310 histologically verified FNAs, the positive predictive values (%) for malignancy and neoplasia (carcinoma + follicular adenomas) for category I-VI according to the TBSRTC were 5.7/11.3, 2.6/5.5, 14.4/34.2, 23.6/55.0, 57.0/64.5 and 92.2/94.2, respectively. Although all the categories predict malignancy closely, the difference in malignancy rate between categories III and IV was not statistically significant; however, the difference in total neoplasia rate reached statistical significance. When patients with cytological and clinical follow-up were included, the malignancy rated dropped in category I to 2.4%, whereas, in category III, it remained at 13%. Repeat FNA instead of direct surgery spared half of the patients from surgery. The cytopathologists' recommendations for histological verification in category III were associated with an insignificant increase in malignancy rate, but the total neoplasia rate reached 57.5%. CONCLUSIONS: At our institution, the application of the TBSRTC did not improve the diagnostic accuracy for the detection of malignancy compared with current practice. In selected cases with cytological results falling into category III (according to clinical data and cytopathologists' opinions), direct lobectomy seems to be justified.

Fine needle aspiration cytology of nodular thyroid lesions: a 2-year experience of the Bethesda system for reporting thyroid cytopathology in a large regional and a university hospital, with histological correlation.

OBJECTIVE: Thyroid fine needle aspiration (FNA) contributes to the appropriate management of nodular thyroid lesions. The introduced categories in the Bethesda system for reporting thyroid cytopathology (TBSRTC) are associated with an implied cancer risk, providing a clinical management guideline. This study aims to evaluate the reproducibility of this implied risk and to compare the results from two different cytopathology departments. METHODS: Five hundred histologically confirmed FNAs, studied since the introduction of TBSRTC, were obtained from 4208 and 3587 FNAs performed in a large regional hospital in Herakleion, Crete (group A) and a university hospital in Athens (group B), respectively. Reports were issued according to TBSRTC. Aspirates were prepared with ThinPrep(®) and evaluated by two experienced cytopathologists. The reproducibility and accuracy were evaluated. RESULTS: The proportion test for suspicious for malignancy (SFM) and malignant (M) cytology reports (P < 0.0001), and the number of malignancies on histology (P < 0.0001), were significantly higher in group A than in group B, consistent with a higher incidence of thyroid carcinomas in southern Greece. Although the malignancy rates were higher in group A than in group B for all categories, except M (A, 99.3%; B, 100%), the difference was only significant for benign aspirates (P = 0.0303). Malignancy rates for all categories in group A were above the TBSRTC recommended range, but were consistent with an increased prevalence of malignancy in that centre, differences in reporting practice and the variable ranges reported in the literature. There was lower sensitivity (P = 0.019) and overall accuracy (P = 0.003) in group A relative to group B, but no difference in specificity. CONCLUSIONS: TBSRTC provides valuable information for the appropriate management of nodular thyroid lesions, both in a university and a large regional hospital.

Diagnostic interobserver agreement for thyroid fine-needle aspirates: Effects of reviewer experience and molecular diagnostics.

OBJECTIVES: Few cytologically indeterminate thyroid fine-needle aspirations (FNAs) harbor BRAF V600E. Here, we assess interobserver agreement for The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) category III (atypia of undetermined significance [AUS]) FNAs harboring BRAF V600E and contrast their features with those harboring non-BRAF V600E alterations, with attention to cytopathology experience. METHODS: Seven reviewers evaluated 5 AUS thyroid FNAs harboring BRAF V600E. To blind reviewers, cases were intermixed with 19 FNAs falling within other TBSRTC categories and in which genetic alterations other than BRAF V600E had been identified (24 FNAs total). Interobserver agreement against both "index" and most popular ("mode") diagnoses was calculated. Four additional BRAF V600E cases were independently reviewed. RESULTS: Reviewers included 3 trainees and 3 American Board of Pathology (board)-certified cytopathologists. Board-certified cytopathologists, whose experience ranged from 2 to more than 15 subspecialty practice years, had known AUS rates. BRAF V600E was identified in 5 of 260 (2%) AUS FNAs. Interobserver agreement was higher among cytopathologists with more experience. Mode diagnosis differed from index diagnosis in 6 of 11 cases harboring RAS-like alterations; mode diagnosis was AUS in 4 of 5 BRAF V600E FNAs. CONCLUSIONS: Atypia of undetermined significance of thyroid FNAs harboring BRAF V600E is uncommon yet relatively reproducible, particularly among pathologists with experience. It is advisable to sequence BRAF across V600 in such cases.

Cytology and Histology of Thyroid Nodules: Exploring Novel Insights in the Molecular Era for Enhanced Patient Management.

Significant advancements have been made over the past decade in our understanding of thyroid cancers, encompassing histomorphology, cytology, and ancillary techniques, particularly molecular tests. As a result, it is now feasible to put forth a comprehensive histo/cytomolecular approach to treating these tumors, thereby offering patients treatments that are precisely tailored to their unique circumstances.

The Role of Cytomorphometric Image Analysis in the Diagnosis of Thyroid Nodules.

Introduction Fine needle aspiration cytology (FNAC) plays a vital role in the diagnosis of thyroid nodules. However, it is challenging due to the heterogeneity of thyroid nodules, overlapping cytomorphological features, and interobserver variability. Cytomorphometric analysis turns subjective observations into quantitative values. In this study, we performed cytomorphometric image analysis on cytological smears of thyroid nodules, classified according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). Materials and methods A retrospective analysis of Papanicolaou (PAP) and Hematoxylin & Eosin (H&E) stained fine needle aspirate smears from 50 patients with thyroid nodules with available follow-up histopathology was performed for a period of two years (March 2021 - March 2023), after obtaining approval from the institutional human ethical committee (IHEC-LOP/2020/IM0355). The nodules were categorized according to TBSRTC and were then subjected to cytomorphometric image analysis. Each nucleus was analyzed for 14 parameters, including aspect ratio, intensity, diameter, perimeter, roundness, area, fractal dimension, feret diameter, circularity, radii, fournier description, and chromatin texture parameters such as heterogeneity and clumpiness. The data obtained was analyzed through relevant statistical methods using SPSS version 23 (IBM Inc., Armonk, New York) and was compared by using the analysis of variance (ANOVA) test and post hoc test. Results Our results revealed that cytomorphometric image analysis not only distinguishes benign and malignant thyroid nodules but also can aid in categorizing thyroid nodules with predominant follicular patterns, such as follicular variant of papillary carcinoma, follicular adenoma and follicular carcinoma (p<0.001). Conclusions Morphometric analysis of cytological smears combined with cytomorphology has the potential to be an important tool in the diagnosis of thyroid nodules. It can improve diagnostic accuracy for better treatment and improved prognosis.

Evaluating local thyroid cytopathology practices by molecular quality metrics: A multi-institutional study on 4651 FNAs with a focus on the role of the interventional cytopathologist.

BACKGROUND: The diagnostic accuracy of thyroid fine-needle aspiration (FNA) can be highly influenced by the technical skills of the operator performing the procedure and by interobserver variability in microscopic interpretation. This is particularly true for the indeterminate categories. Recently, molecular testing has been proposed as an ancillary tool for monitoring the performance of different thyroid cytopathology practices. The objective of this multicenter study was to evaluate the quality of different local cytopathology practices by assessing the impact of interventional cytopathologists on FNA adequacy for molecular testing and the variations in mutation rates across different health care centers operating in the Campania region. METHODS: The study included 4651 thyroid FNA samples diagnosed in different Southern Italian clinical laboratories belonging to the TIRNET (the Tiroide Network). FNA samples were collected by different proceduralists and were classified by local cytopathologists according to The Bethesda System for Reporting Thyroid Cytopathology. FNAs classified as atypia of undetermined significance, follicular neoplasm, suspicious for malignancy, and malignant were centralized for a real-time polymerase chain reaction-based, seven-gene test at the authors' institution. RESULTS: Centers that employed interventional cytopathologists obtained fewer unsatisfactory FNA samples for molecular testing (11.3%) than centers that employed noncytopathologists (16.7%; p < .05). Furthermore, a significant variation in the mutation rate was observed in FNAs diagnosed by different local cytopathologists; indeterminate categories had the highest percentage of mutation rate variability among centers. CONCLUSIONS: Interventional cytopathologists obtained higher yields of diagnostic material for molecular testing. Finally, the current results suggest that the variability in mutation rates among different centers may highlight the low reproducibility of microscopic criteria among cytopathologists, particularly for indeterminate cases.

Use of molecular testing results to analyze the overuse of atypia of undetermined significance in thyroid cytology.

INTRODUCTION: The suggested atypia of undetermined significance (AUS) rate for thyroid fine-needle aspiration biopsies is 10% or less. Prompted by a high institutional AUS rate, we examined using molecular testing results (MTR) as a potential quality metric tool to reduce the AUS rate. We correlated MTR with AUS cytologic findings, surgical pathology follow-up, and individual pathologist AUS rates. MATERIALS AND METHODS: Demographic data, cytologic diagnoses, MTR, and surgical pathology diagnoses were retrospectively obtained. MTR were classified as either positive or negative. AUS rates and MTR proportions were compared among pathologists. The cytomorphologic features of 143 AUS cases were assessed and correlated with MTR. RESULTS: Between 2017 and 2022, 710 of 3247 thyroid fine-needle aspirations were classified as AUS, with a yearly average rate of 22% (range = 19%-26%). AUS cases included: 331 (47%) with architectural atypia; 204 (29%) with oncocytic (Hürthle cell) atypia; 99 (14%) with combined architectural and cytologic atypia; and 76 (10%) with isolated cytologic atypia. Most AUS cases with molecular testing had negative MTR (360/492, 73%). AUS with cytologic atypia had higher positive MTR risk (logarithm of odds ratio = 1.27, 95% credible interval [0.5-2.04], P = 0.001). The average positive MTR rate by pathologist was 21.5% (range 0%-35%); higher positive MTR rates had better correlation with subsequent neoplastic/malignant histologic diagnoses. The MTR sensitivity for malignant disease was 89% and the negative predictive value was 91%. CONCLUSIONS: MTR analysis reveals the importance of cytologic atypia as a determinant of malignancy risk in AUS cases. Periodic analysis of MTR data alongside individual pathologist AUS rates can help refine diagnostic criteria and potentially reduce AUS overuse.

Reproducibility of Cytomorphological Diagnosis and Assessment of Risk of Malignancy of Thyroid Nodules Based on the Bethesda System for Reporting Thyroid Cytopathology: A Tertiary Cancer Center Perspective.

Introduction: The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) was introduced for unifying the terminology and morphologic criteria along with the corresponding risk of malignancy, leading to more consistent management approaches. The aim of this study was to study the utility and reproducibility of TBSRTC in reporting thyroid cytology in a referral cancer center. Methods: The fine-needle aspiration (FNA) of all thyroid nodules were included for a period of 5 years, from January 2016 to December 2021, in this cancer center. They were retrospectively reviewed and recategorized according to TBSRTC by two experienced pathologists. Cytohistopathological correlation was done for the cases which underwent surgical resection. Results: 522 fine-needle aspiration cytology (FNAC) of thyroid swellings were evaluated and categorized according to TBSRTC. There was agreement in the cytological diagnosis of 512 cases, of which 260 (50.78%) were benign lesions, 189 (36.91%) were malignant, 5 (0.97%) were unsatisfactory/nondiagnostic, 41 (8.01%) were follicular neoplasm/suspicious for neoplasm, 13 (2.53%) were suspicious for malignancy, and 4 (0.78%) cases were reported as atypia of undetermined significance. Two cytopathologists were in agreement in 512 cases (98%) of cases. Almost complete concordance was noted in the malignant (99%) and benign categories (98%). Disagreement was seen in 10 cases. Histological follow-up was available in 201 cases with an overall malignancy rate of 62.68% (126/201). Conclusion: TBSRTC proved to be a very simple and effective reporting system for thyroid FNAC, especially in the setting of a cancer center. This enables proper triaging of cases with thyroid masses into those who require surgical intervention and those who can avoid it, thereby preventing unnecessary morbidity.

NTRK-rearranged papillary thyroid carcinoma demonstrates frequent subtle nuclear features and indeterminate cytologic diagnoses.

BACKGROUND: The studies on the cytomorphologic features of NTRK-rearranged papillary thyroid carcinoma (PTC) are limited and some reported characteristics, such as frequent indeterminate diagnoses and presence of fibrotic fragments, are inconsistent in literature. METHODS: NTRK gene rearrangements were detected in thyroidectomy specimens of PTC by either fluorescence in situ hybridization or next-generation sequencing. All the cytologic slides of NTRK-rearranged PTC were reviewed to evaluate the cytomorphologic features. The preoperative cytologic diagnoses of NTRK-rearranged PTC were compared with those of NTRK/BRAF wild-type and BRAFV600E -positive PTC. RESULTS: Fourteen PTC cases were identified to harbor NTRK gene rearrangements. Most of them showed a mixed architectural pattern of cell fragments (n = 13, 92.9%) and microfollicles (n = 9, 64.3%) with relatively rare papillary structures (n = 4, 28.6%). Nuclear grooving was frequently present (n = 11, 78.6%) but was mostly subtle and limited. Seven cases (50.0%) showed rounded nuclei without discernible nuclear elongation, and only 3 (21.4%) cases presented with nuclear pseudoinclusions. Among these cases, 7 (50.0%) were diagnosed as The Bethesda System for Reporting Thyroid Cytopathology (TBS) category III, 2 (14.3%) were diagnosed as TBS IV, and 5 (35.7%) were diagnosed as TBS V. The rate of TBS III-IV diagnoses for NTRK-rearranged PTCs was significantly higher (64.3%) than that for the 25 consecutive NTRK/BRAF wild-type PTCs (20.0%, P = .013) and the 70 consecutive BRAFV600E -positive PTCs (7.1%, P < .001) as selected. CONCLUSIONS: NTRK-rearranged PTC demonstrated intermediate nuclear features, such as subtle nuclear grooving, infrequent nuclear elongation, and rare pseudoinclusions, resulting in a significantly higher rate of TBS III-IV diagnoses compared to PTC with other molecular alterations.

Noninvasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features (NIFTP): Tumour Entity with a Short History. A Review on Challenges in Our Microscopes, Molecular and Ultrasonographic Profile.

Since Noninvasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features (NIFTP) was introduced as a new thyroid tumour entity, many studies, and meta-analyses on diagnosing NIFTP have been published. NIFTP-revised histopathological criteria emerged in 2018. NIFTP is defined as a histological entity and its diagnosis requires a careful histological examination. Its molecular profile is similar to follicular-like tumours. Ultrasound features are unable to differentiate NIFTP. NIFTP is not a cytological diagnosis, but it influences the risk of malignancy in several categories of The Bethesda System for Reporting Thyroid Cytopathology terminology.

Combining molecular testing and the Bethesda category III:VI ratio for thyroid fine-needle aspirates: A quality-assurance metric for evaluating diagnostic performance in a cytopathology laboratory.

BACKGROUND: Molecular testing (MT) of thyroid fine-needle aspiration (FNA)-derived genetic material is commonly used to assess malignancy risk for indeterminate cases. The Bethesda System for Reporting Thyroid Cytopathology (TBS) provides limited guidance for the appropriate use of category III (atypia of undetermined significance [AUS]). The authors combined MT with cytomorphology to monitor AUS diagnoses in a cytopathology laboratory. METHODS: Neoplasia-associated genetic alterations (NGAs) were determined by MT of preoperative FNA biopsies or resected malignancies and were categorized as BRAF V600E mutations, RAS-like mutations (HRAS, NRAS, or KRAS mutations or non-V600E BRAF mutations), or other mutations. RESULTS: Among 7382 thyroid FNA biopsies, the AUS rate was 9.3% overall and ranged from 4.3% to 24.2% among 6 cytopathologists (CPs) who evaluated >150 cases. The ratio of specimens falling into TBS category III to specimens falling into category VI (malignant) (the III:VI ratio) was 2.4 overall (range, 1.1-8.1), and the ratio of specimens falling into TBS categories III and IV (follicular neoplasm or suspicious for follicular neoplasm) combined (III+IV) to specimens falling into category VI (the [III+IV]:VI ratio) was 2.9 overall (range, 1.4-9.5). MT was performed on 588 cases from 560 patients (79% women) with a median age of 56 years (range, 8-89 years). BRAF V600E mutation was the most common (76% of cases) in TBS category VI and was rare (3%) in category III. RAS-like mutations were most common in TBS categories III (13%), IV (25%), and V (suspicious for malignancy) (17.5%). The NGA rate in AUS cases fell between 5% and 20% for 5 of 6 CPs and did not correlate with the III:VI ratio or the (III+IV):VI ratio. CONCLUSIONS: Lack of correlation between the NGA rate and easily calculable diagnostic ratios enables the calibration of diagnostic thresholds, even for CPs who have normal metrics. Specifically, calculation of the NGA rate and the III:VI ratio may allow individual CPs to determine whether they are overcalling or undercalling cases that other CPs might otherwise recategorize.

Utility of Fine-Needle Aspirations to Diagnose Pediatric Thyroid Nodules.

INTRODUCTION: Risk of malignancy for pediatric thyroid nodules classified according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) is not well defined. Correlations between risk of malignancy and ancillary clinical data remain inconclusive. We report a single institutional experience of fine-needle aspiration (FNA) to improve upon current management paradigm of thyroid nodules. METHODS: A retrospective chart review of 575 thyroid nodules was performed of 324 patients who underwent 340 FNAs between 2008 and 2018 at the Children's Hospital of Philadelphia. Demographics, ultrasound (US) characteristics, FNA cytology, surgical pathology, and ancillary data were reviewed. RESULTS: The rate of malignancy according to TBSRTC was 0.0% for category I, 0.8% for category II, 15.6% for category III, 54.5% for category IV, 100.0% for category V, and 100.0% for category VI. The cumulative Thyroid Imaging Reporting and Data System (TI-RADS) score was significantly correlated with benign and malignant nodules on pathology (p < 2.2e-16). Distribution of TI-RADS for cytologically indeterminate nodules with benign or malignant pathology revealed significant differences for composition (p = 3.20e-8) and echogenic foci (p = 0.005) but not for echogenicity (p = 0.445), shape (p = 0.160), margins (p = 0.220), and size (p = 0.105). Distributions of thyroid-stimulating hormone levels between benign and malignant patients was significant (p = 1.58e-3). CONCLUSIONS: Nodules with TI-RADS scores >3 should undergo FNA, irrespective of size; surgical resection is recommended for nodules classified as TBSRTC category IV and V due to high risk of malignancy. US surveillance instead of FNA can be performed for nodules with TI-RADS scores ≤3.

Diagnostic performances of the Afirma Gene Sequencing Classifier in comparison with the Gene Expression Classifier: A meta-analysis.

The Afirma microarray-based Gene Expression Classifier (GEC) with its high negative predictive value (NPV) and sensitivity has been used to rule out cancer from thyroid nodules with an indeterminate cytology but not to rule in cancer because of its low positive predictive value (PPV) and specificity. The Gene Sequencing Classifier (GSC) has been reported to improve on the weakness of GEC. In this study, a meta-analysis was performed to compare the clinical impact and diagnostic performance of GEC and GSC. Relevant data were searched in PubMed and Web of Science. Meta-analyses for proportion and dichotomous outcomes were performed to compare the benign call rates (BCRs), resection rates (RRs), risks of malignancy (ROMs), sensitivities, specificities, PPVs, and NPVs of GSC and GEC. Seven studies were included for the meta-analyses. Compared with GEC, GSC had a higher BCR (65.3% vs 43.8%; P < .001), a lower RR (26.8% vs 50.1%; P < .001), and a higher ROM (60.1% vs 37.6%; P < .001). The BCR of Hürthle cell-predominant nodules was significantly elevated (73.7% vs 21.4%; P < .001). In addition, the specificity (43.0% vs 25.1%; P = .003) and PPV (63.1% vs 41.6%; P = .004) of Afirma GSC were significantly improved while it still maintained a high sensitivity (94.3%) and a high NPV (90.0%). In conclusion, this study confirms and highlighted the clinical and diagnostic significance of GSC. With an increased BCR and improved diagnostic performance, GSC could reduce the rate of unnecessary surgical interventions and better tailor the clinical decisions of patients with indeterminate thyroid fine-needle aspiration results.

Characterization of "suspicious for malignancy" for non-papillary carcinoma diagnoses on thyroid fine-needle aspiration.

INTRODUCTION: To evaluate the incidence, risk of malignancy, and management of "suspicious for malignancy" (SFM) for non-papillary carcinoma diagnoses according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). MATERIALS AND METHODS: A retrospective search was performed for all thyroid fine-needle aspirations (FNAs) with an SFM diagnosis in the electronic Pathology database at The Johns Hopkins Hospital from 2000 to 2019. During this period, a total of 644 cases were diagnosed as SFM. Of these, 55 cases of "suspicious for non-papillary thyroid carcinoma" (SNPTC) were identified. These 55 cases were then compared with 65 random cases of "suspicious for papillary thyroid carcinomas" (SPTC) diagnoses as a control group. RESULTS: The SNPTC subgroup consisted of 28 cases of "suspicious for medullary thyroid carcinoma" (SMTC) (50.91%), 4 cases of "suspicious for metastasis" (SMET) (7.27%), 3 cases of "suspicious for malignant lymphoma" (SML) (5.45%), 2 cases of "suspicious for poorly-differentiated thyroid carcinoma" (SPDC) (3.64%), and 18 cases of "suspicious for malignancy, not otherwise specified" (SNOS) (32.73%). When compared to SPTC, SNPTC patients' average age was older (P = 0.004). Ancillary studies assisted in diagnosing SNPTC more so than SPTC (P < 0.001). Immunohistochemical studies were performed for 11 cases, molecular studies for 6 cases, and needle rinse calcitonin level for 1 case. When correlated with surgical follow-ups, the risk of malignancy (ROM) was 91.18% for SNPTC compared to 93.75 for SPTC%. CONCLUSIONS: SNPTC was rarely diagnosed when compared with SPTC. SMTC was the most commonly diagnosed SNPTC subgroup, followed by SNOS. The ROM of SNPTC was slightly lower than that of SPTC. Ancillary studies and previous clinical history, in addition to cytomorphology, was helpful when rendering the diagnosis of SNPTC.

An overview of thyroid fine-needle aspiration practice in Myanmar.

Fine-needle aspiration cytology (FNAC) of the thyroid is a widely accepted method for aiding the diagnosis of thyroid nodules. In Myanmar, it has been done since the early 1990s, and mainly performed by surgeons and otorhinolaryngologists. The interpretation of cytology is solely made by pathologists. Although some of the experts particularly those from specialist hospitals use the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), many still prefer the British five-tier cytopathology report. Available local publications addressing the accuracy of FNAC and cytologic-histologic correlations were queried. Ten studies performed in 1991-2018 on 540 thyroid nodules were included. Cytologic-histologic correlations showed a range of sensitivity from 64.29% to 100%, specificity from 93% to 100%, and diagnostic accuracy from 94% to 100%. The adoption of TBSRTC by pathologists is still slow and should be encouraged via seminars and training programs. Further multihospital-based large cohort studies with uniform design and adequate follow-up are needed to better promote and assess utility of thyroid FNAC in Myanmar.

Utility of cell block as an adjunct to liquid-based cytology for diagnosing papillary thyroid carcinoma.

BACKGROUND: Although liquid-based cytology (LBC) has gained popularity among clinical laboratories, it is unclear whether it is equivalent to conventional smears for making a definite diagnosis of papillary thyroid carcinoma (PTC). The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) suggests a definite diagnosis of PTC is preferred when there are at least one of three features (papillary architecture, psammomatous calcifications, and frequent pseudonuclear inclusions) plus other typical cytomorphological findings. This study evaluated whether an additional cell block (CB), prepared from the residual LBC material, could help improve the diagnosis of PTC. MATERIALS AND METHODS: A total of 62 cases with both ThinPrep LBC and CB preparations and histopathological follow-up of PTC were retrieved between November 2016 and March 2019. The ThinPrep LBC and CB slides were reviewed separately to identify any papillary architecture, psammomatous calcifications, or pseudonuclear inclusions for diagnosing PTC. RESULTS: Among the 51 cases with cytological diagnosis of PTC in the LBC+CB slides, the CB provided additional diagnostic information in 15 cases, which were initially diagnosed as suspicious for PTC based on the LBC slides alone. This information included papillary architecture (n=11), psammomatous calcification (n=1) and pseudonuclear inclusions (n=5). The number of specimens in the 51 cases containing at least one of the three features increased from 42 (LBC) to 51 (LBC+CB). The accuracy for diagnosing PTC increased from 58.1% for LBC alone to 82.3% for the LBC+CB examination. CONCLUSION: An adjunctive CB preparation may improve the LBC technique for diagnosing PTC.

The diversities in thyroid cytopathology practices among Asian countries using the Bethesda system for reporting thyroid cytopathology.

BACKGROUND: The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) has been adopted and widely used among Asian countries. This study aims to investigate the application of TBSRTC in thyroid cytology practice among Asian countries. METHODS: We searched electronic databases including PubMed and Web of Science from 2010 to 2019. Meta-analysis of proportion and their 95% confidence intervals (CIs) were calculated using the random-effect model. Meta-regression and subgroup analysis were used to search for heterogeneity origins. RESULTS: We included 42 Asian studies with 84.953 fine-needle aspirations. Among six categories, benign was the most commonly diagnosed category. The resection rate (RR) and risk of malignancy (ROM) were highest in malignant and SM categories, and lowest among benign nodules. Thyroid cytology practice in Asia was characterized by a low RR and high ROM in patients with indeterminate thyroid nodules. There was a significant amount of heterogeneities of TBSRTC outputs (frequency, resection rate, and malignancy risk) among Asian countries. Meta-regression showed that the sources of heterogeneity might stem from the differences in study origin and the application of molecular testing. We highlighted the usefulness of preoperative molecular testing to select patients for surgery. CONCLUSIONS: Our study provided insight regarding thyroid cytology practice among Asian countries. Active surveillance is commonly used in Asian practice resulting in a low RR and high ROM for indeterminate nodules. There are still variations in general thyroid cytology practice in Asia. Future guidelines and consensus regarding the application of TBSRTC in thyroid cytology practice among Asian countries are required.

The importance of risk of neoplasm as an outcome in cytologic-histologic correlation studies on thyroid fine needle aspiration.

BACKGROUND: The introduction of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) altered the practice of thyroid pathology and reduced the risk of malignancy (ROM) associated with the indeterminate categories in the Bethesda system for reporting thyroid cytopathology (TBSRTC). It has been proposed that the evaluation of the risk of neoplasm (RON) is important in cytologic-histologic correlation studies. METHODS: A total of 5224 thyroid aspirates were performed at our institution during an 8-year period. Of the 1475 cases (28%) with surgical follow-up, the histologic diagnoses comprised benign non-neoplastic (BNN, n = 669), follicular adenoma (FA, n = 188), NIFTP (n = 42), papillary microcarcinoma (PMC) (n = 223), and malignant neoplasm excluding PMC (n = 353). The RON was calculated to include neoplasia with low risk biologic behavior (FA, NIFTP, PMC) and malignant neoplasms. In contrast, the ROM was reserved for malignant neoplasms excluding PMC. RESULTS: The RON for each TBSRTC category was: nondiagnostic (ND) 38.3%, benign 20.9%, atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) 63.2%, follicular neoplasm or suspicious for follicular neoplasm (FN/SFN) 83.9%, suspicious for malignancy (SFM) 94%, and malignant 100%. The ROM excluding PMC was: ND 14%, benign 1.6%, AUS/FLUS 17.8%, FN/SFN 28.4%, SFM 84.4%, and malignant 99.5%. CONCLUSIONS: The RON and ROM support the recommended management guidelines from TBSRTC for all categories, except for FN/SFN. Histopathologic follow-up of FN/SFN aspirates in our study contain a very high rate of neoplasm (83.9%), which might support the management preference of conservative surgery.

Does a higher American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) score forecast an increased risk of malignancy? A correlation study of ACR TI-RADS with FNA cytology in the evaluation of thyroid nodules.

BACKGROUND: Ultrasound has become the initial approach to evaluating thyroid nodules, facilitating the distinction between benign and malignant nodules based on composition, echogenicity, nodule border or margin, shape, the presence of calcifications, and nodule dimensions. The American College of Radiology (ACR) recommended the Thyroid Imaging Reporting and Data System (TI-RADS) as a classification system to standardize thyroid ultrasound reports and to predict the probability of malignancy in thyroid nodules using a scoring system (TR1-TR5) based on multiple ultrasound characteristics and nodule size. Fine-needle aspiration (FNA) is recommended as the next step for nodules that warrant further workup. The authors assessed the accuracy of the ACR TI-RADS based on the corresponding FNA cytology results (Bethesda system diagnoses I-VI). METHODS: ACR TI-RADS ultrasound reports and corresponding FNA cytology diagnoses from January 1, 2018 to August 30, 2018 were evaluated. RESULTS: From January 1, 2018 to August 30, 2018, 2306 thyroid ultrasound-guided FNAs were performed at our institution. Of 2306 cases, 361 had ACR TI-RADS reports available. The majority of FNAs were TR4 (180; 49.9%) or TR3 (108; 29.9%). No TR2 or TR3 nodules were associated with Bethesda category V or VI diagnoses. The majority of TR4 nodules (142 of 180; 78.9%) and TR5 nodules (42 of 65; 64.6%) exhibited benign (Bethesda category II) cytology. Fourteen TR5 cases (21.5%) had malignant (Bethesda category VI) cytology. CONCLUSIONS: Although there were no TR2 or TR3 malignant (Bethesda category VI) diagnoses, and there were only a few malignancies in the TR4 and TR5 categories, the current results reassert the notion that the ACR TI-RADS scoring system shows at least some correlation between benign or malignant cytology diagnoses, as illustrated by the greater number of malignant cases in the higher ACR TI-RADS categories.