Follicular Neoplasm/suspicious For Follicular Neoplasm Research Articles

Impact of the Reclassification of "Noninvasive Encapsulated Follicular Variant of Papillary Thyroid Carcinoma" to "Noninvasive Follicular Thyroid Neoplasm With Papillary-Like Nuclear Features" on the Bethesda System for Reporting Thyroid Cytopathology: A Large Academic Institution's Experience.

Noninvasive encapsulated follicular variant of papillary thyroid carcinoma (NEFVPTC) was recently reclassified as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Excluding "carcinoma" from the new terminology shifted NIFTP out of the malignant category and altered Bethesda System for Reporting Thyroid Cytopathology (BSRTC) rates of malignancy (ROMs) on thyroid fine-needle aspiration (FNA). Because of potential effects on management guidelines, we examined our ROM data. In total, 750 thyroid FNAs with surgical resections from January 2013 to June 2016 were reviewed (including 87 NIFTPs). ROM was recorded for each BSRTC category: classifying NEFVPTC/NIFTP as "malignant" and reclassifying NEFVPTC/NIFTP as "nonmalignant." ROM changes were as follows: nondiagnostic (ND), no change; benign, 5.5% to 2.5%; atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 42.3% to 22.3%; follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), 48.7% to 17.9%; suspicious for malignancy (SFM), 93.6% to 61.7%; and positive for malignancy, 100% to 97%. Decreased ROM was seen in most BSRTC categories, most significantly in AUS/FLUS, FN/SFN, and SFM categories.

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features in the pediatric age group.

The most common malignant thyroid neoplasm in children is papillary thyroid carcinoma (PTC). In 2015, the Endocrine Pathology Society introduced the terminology "noninvasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP) to replace the noninvasive follicular variant of PTC. The objective of the current study was to evaluate previously diagnosed PTC in the pediatric population, reappraise it for NIFTP, and discuss the impact of NIFTP on the risk of malignancy (ROM) for each The Bethesda System for Reporting Thyroid Cytopathology category in the pediatric population. The electronic databases of both study institutions were searched for all thyroidectomy specimens in patients aged <19 years from June 1, 2001 through June 1, 2016. The patient's age, sex, diagnosis, previous fine-needle aspiration cytology diagnosis, and follow-up were tabulated. Slides for available cases were reviewed and cases qualifying as NIFTP were separated. The cohort included 101 resected nodules; cytological diagnoses were available for 95 cases. These cases included diagnoses of nondiagnostic (5 cases; 5.2%), benign (21 cases; 22.1%), atypia/follicular lesion of undetermined significance (9 cases; 9.5%), follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) (25 cases; 26.3%), suspicious for malignancy (7 cases; 7.4%), and malignant (28 cases; 29.5%). On the histological follow-up, 50 cases (49.5%) were benign, 49 cases (48.5%) were malignant, and 2 cases (1.9%) were NIFTP. These NIFTP cases originally were diagnosed as FNs on fine-needle aspiration cytology. The average ROM for FNs with and without NIFTPs was 28% and 25%, respectively CONCLUSIONS: According to our rate of 1.9% for NIFTPs on reappraisal for resected nodules, this entity is likely to be less frequent in the pediatric population due to the higher prevalence of PTCs and/or more aggressive variants. NIFTPs do not appear to affect the ROM for The Bethesda System for Reporting Thyroid Cytopathology categories in the pediatric population. However, large-scale studies are necessary to determine whether NIFTPs could affect the pediatric population. Cancer Cytopathol 2018;126:27-35. © 2017 American Cancer Society.

Fine Needle Aspiration of Thyroid Nodules Using the Bethesda System for Reporting Thyroid Cytopathology: An Institutional Experience in a Rural Setting.

Background. Fine needle aspiration (FNA) remains the first-line diagnostic in management of thyroid nodules and reduces unnecessary surgeries. However, it is still challenging since cytological results are not always straightforward. This study aimed to examine the results of thyroid FNA using the Bethesda system for reporting thyroid cytopathology (TBSRTC) to establish the level of accuracy of FNA procedures in a rural practice setting. Method. A retrospective chart review was conducted on existing thyroid FNA performed in a referral endocrine center between December 2011 and November 2015. Results. A total of 159 patients (18–88 years old) and 236 nodule aspirations were performed and submitted for evaluation. 79% were benign, 3% atypia/follicular lesion of unknown significance (AUS/FLUS), 5% follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), 4% suspicious for malignancy (one case was indeed an atypical parathyroid neoplasm by surgical pathology), 2% malignant, and 7% nondiagnostic. Two cases also had advanced molecular analysis on FNA specimens before thyroidectomy. Conclusion. The diagnostic yield of FNA cytology from our practice in a rural setting suggests that accuracy and specificity are comparable to results from larger centers.

Bethesda classification is a valuable guide for fine needle aspiration reports and highly predictive especially for diagnosing aggressive variants of papillary thyroid carcinoma.

A fine needle aspiration biopsy (FNAB) is the most valuable diagnostic procedure for pre-operative discrimination of benign and malignant nodules. The Bethesda System for Reporting Thyroid Cytopathology provides standardised reporting and cytomorphological criteria in aspiration smears. The aim of the present study was to determine malignancy rates in nodules with different cytology results and evaluate the diagnostic value of Bethesda for variants of papillary thyroid carcinoma (PTC). A retrospective analysis of 2534 cases with 5784 thyroid nodules, who underwent FNAB followed by surgery, were included in this study. FNAB was performed with ultrasonography guidance. Cytological diagnoses were classified as: non-diagnostic (ND), benign, atypia of undetermined significance/follicular lesions of undetermined significance (AUS/FLUS), follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), suspicious for malignancy (SUS) and malignant. Histopathological diagnoses were classified into four groups: benign, PTC, follicular thyroid cancer and other types of thyroid cancer (including medullary thyroid cancer, undifferentiated thyroid cancer and thyroid tumours of uncertain malignant potential). Cases with PTC were further divided into four categories: conventional variant, follicular variant, aggressive variants (tall cell, diffuse sclerosing and columnar variant) and other variants (oncocytic, solid/trabecular and warthin-like variants). FNAB results were compared with histopathological results. Malignancy rates were 6.3%, 3.2%, 20.7%, 33.3%, 74.2% and 95.6% in the nodules with ND, benign, AUS/FLUS, FN/SFN, SUS and malignant cytology results, respectively. Pre-operative cytology was malignant or SUS in 56.6% of conventional, 24.3% of follicular, 92% of aggressive and 41.7% of other variants of histopathologically confirmed PTC. The difference between the groups was significant (P < 0.001). The Bethesda classification is a reliable indicator of malignancy in nodules with different cytology results and seems to be very effective in predicting the malignancy for the nodules diagnosed with aggressive variant PTC on the final histological examination.

Fine needle aspiration cytology of thyroid nodules: a cytopathologic study of 2 043 cases

To evaluate the clinical value of thyroid fine needle aspiration cytology(FNAC) and the Bethesda system for reporting thyroid cytopathology(TBSRTC). FNAC was performed for 2 043 cases and cytopathological data were retrospectively analyzed. Cytopathological diagnoses according to TBSRTC were classified as non-diagnostic, benign, atypia of undetermined significance/follicular lesion of undetermined significance(AUS/FLUS), follicular neoplasm/suspicious for follicular neoplasm(FN/SFN), suspicious for malignancy(SM) and malignancy. The results of 234 FNAC samples in which surgery was performed were compared with the histological diagnoses. Of the 2 043 FNAC samples, 15.7%(320/2 043)were non-diagnostic, 51.2%(1 047/2 043)were benign, 16.6%(339/2 043) were AUS/FLUS, 2.3%(46/2 043)were FN/SFN, 8.6%(176/2 043)were SM and 5.6%(115/2 043)were malignant. In 234 cases, there was follow-up histology. Rates of malignancy were as follows: non-diagnostic, 18.2%(2/11); benign(2.2%, 1/45); AUS/FLUS(25.6%, 10/29); FN/SFN(12.1%, 10/39); SM(91.8%, 56/61); malignant(100.0%, 45/45). The sensitivity, specificity, false positive rate, false negative rate and overall accuracy of FNAC in the diagnosis of thyroid nodules was 87.1%(101/116), 95.3%(102/107), 4.7%(5/107), 12.9%(15/116), 91.0%(203/223). FNAC is a reliable diagnostic method for evaluation of thyroid disease. TBSRTC is a accurate and effective reporting system for cytopathological diagnoses, so it is worthy of being widely popularized in clinical application.

Higher TSH can be used as an additional risk factor in prediction of malignancy in euthyroid thyroid nodules evaluated by cytology based on Bethesda system.

Recently, it has been suggested that thyrotropin (TSH) concentration can be used as a marker for prediction of thyroid malignancy. In this study, we aimed to investigate the association between TSH levels and prediction of malignancy in euthyroid patients with different Bethesda categories. The data of 1433 euthyroid patients with 3206 thyroid nodules who underwent thyroidectomy were screened retrospectively. The preoperative cytology results, thyroid function tests, thyroid autoantibodies, and presence of histopathological Hashimoto's thyroiditis (HT) were recorded. Of the 1433 patients, 585 (40.8%) had malignant and 848 (59.2%) had benign histopathology. Malignant group had smaller nodule size, elevated TSH levels, and higher rate of presence of HT compared to benign group (p<0.001, all). Cytology results of 3206 nodules were as follows: 832 nondiagnostic (ND), 1666 benign, 392 atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 68 follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), 133 suspicious for malignancy (SM), and 115 malignant. Both SM and malignant cytology groups had higher TSH levels than other 4 Bethesda categories (p<0.05, all). Benign cytology group had significantly lower TSH levels compared to other cytology groups (p<0.05, all). Patients with malignant final histopathology in ND and AUS/FLUS cytology groups had significantly higher TSH levels compared to patients with benign final histopathology (p<0.05, all). Moreover, TSH levels showed to increase from Bethesda categories II to VI. In addition to cytology, higher TSH levels can be used as a supplementary marker in prediction of malignancy in certain Bethesda categories.

A study of malignancy rates in different diagnostic categories of the Bethesda system for reporting thyroid cytopathology: An institutional experience

BackgroundThe Bethesda system for reporting thyroid cytopathology (TBSRTC) was introduced to standardize the communication of fine-needle aspiration cytology (FNAC) interpretation between clinicians and pathologists. This study was undertaken to evaluate the diagnostic utility of TBSRTC for reporting thyroid FNACs and rate of malignancy in each diagnostic category of TBSRTC. MethodsA total of 603 thyroid FNAC results were retrieved retrospectively between July 2012 and January 2015 and reclassified according to TBSRTC. Of these, 392 cases had a histopathological follow-up. The FNACs results were compared to the histopathological diagnoses and the malignancy rates of each diagnostic categories of TBSRTC were calculated. ResultsOf the 603 FNACs, nondiagnostic were 16 (2.7%), benign were 393 (65.2%), atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) were 60 (10%), follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN) were 64 (10.6%), suspicious for malignancy (SM) were 32 (5.3%), and malignant were 38 (6.3%). In 392 cases, there was follow-up histopathology. The malignancy rate for nondiagnostic, benign, AUS/FLUS, FN/SFN, SM, and malignant categories were 0%, 0.8%, 24.4%, 28.9%, 70.8%, and 100%, respectively. ConclusionOur study validated the efficacy of TBSRTC. In conclusion, the malignancy rate of AUS/FLUS in this study was higher than the risk mentioned in TBSRTC and other published studies. Hence, AUS/FLUS category patients in our setup warrant further workup including ultrasound and/or thyroid scan in addition to immediate repeat FNAC.

A correlative study of solitary thyroid nodules using the bethesda system for reporting thyroid cytopathology.

Fine needle aspiration cytology (FNAC) is a useful diagnostic modality in the evaluation of solitary thyroid nodules (STN). It can differentiate between benign and malignant lesions in most cases. This study was undertaken to determine the utility and diagnostic accuracy of FNAC in the evaluation of STN. In this retrospective study, a total number of 483 thyroid FNACs were retrieved, out of which 209 cases of STN were chosen for this study. The Bethesda system for reporting thyroid cytopathology (TBSRTC) was used for analysis. Their FNACs diagnoses were compared with histopathological diagnoses. Among 209 FNACs, 88 (42.1%) had non-neoplastic lesions, 6 (2.9%) had atypia of undetermined significance/follicular lesions of undetermined significance (AUS/FLUS), 52 (24.9%) had follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN), 33 (15.8%) were suspicious for malignancy and 18 (8.6%) had malignant cytology. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of FNAC in STN cases were 94.4%, 97.6%, 95.8%, 98.1% and 93.2% respectively. Our study concluded that FNAC reporting using TBSRTC highly correlated with the histopathological diagnosis and our results were comparable with published data. The FNAC diagnosis helps in triaging patients with STN and identifies those who require surgical intervention. It is a simple, convenient, cost effective, sensitive, specific, safe and accurate initial diagnostic method for the preoperative evaluation of STN.

Laser capture microdissection is a valuable tool in the preoperative molecular screening of follicular lesions of the thyroid: an institutional experience.

The application of molecular tests to thyroid fine needle aspiration (FNA) has been shown to be a valuable tool to better refine the pre-operative malignant risk of patients with indeterminate cytology results. In this study, we investigated the feasibility of using the laser capture microdissection (LCM) technique to obtain DNA and RNA for molecular tests in routine thyroid FNA smears. Nine coupled FNA and histological retrospective cases and 31 prospective FNA cases with a follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN) diagnosis were included in this study. Both cytological and histological specimens were investigated by direct sequencing and reverse transcription-polymerase chain reaction (RT-PCR) for BRAF and RAS mutations and for PAX8/PPARG and RET/PTC rearrangements, respectively. LCM yielded good DNA and RNA quality in all cases (100%) in both series, irrespective of the staining used (Giemsa, Papanicolaou, immunostain for thyroglobulin) and the cytology technique (conventional or liquid-based preparations). Total mutations found in the FNA and in the corresponding histological specimen in both series were: one PAX8/PPARG rearrangement in a follicular carcinoma (FC), four NRAS mutations [in two FCs, one papillary carcinoma and one follicular adenoma (FA)] and one HRAS mutation in one FA. The sensitivity was 67% and the specificity was 91%. LCM is a valuable tool to obtain good quality DNA and RNA for molecular tests in cytological material from thyroid FNA, and can be a useful option in the management of patients with an FN/SFN FNA diagnosis.

AACE/ACE Disease State Commentary: Molecular Diagnostic Testing of Thyroid Nodules with Indeterminate Cytopathology

• Approximately 10 to 25% of fine-needle aspiration (FNA) biopsies yield an indeterminate result often labeled as atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS) or follicular neoplasm/suspicious for follicular neoplasm (FN/SFN). The risk of malignancy typically varies between 15 and 30% for these categories. • Although many markers are in development and have been studied in a research setting, 2 principal tests are currently marketed for use to improve the malignancy risk assessment of "indeterminate" thyroid nodules. "Rule In" and "Rule Out" tests attempt to confirm or exclude the presence of cancer within a thyroid nodule by means of robust positive (PPV) or negative predictive values (NPV), respectively. • The Rule In tests determine the presence of single gene point mutations (BRAFV600E or RAS) or gene rearrangements (RET/PTC, PAX8/PPARγ) that have been shown to increase the ability to predict cancer, while the Rule Out test (Afirma® gene expression classifier, GEC) utilizes a proprietary gene expression classifier (RNA expression) specifically designed to maximize the ability to define a process as benign. • Among the presently available tests, only the BRAFV600E and RET/PTC rearrangement are associated with a PPV that approaches 100%. • The category of cytologically "indeterminate" nodule (AUS/FLUS, FN/SFN), cytopathology practice patterns, and the prevalence of malignancy within the population being tested all impact the NPVs and PPVs for the tests in question. • At present, molecular testing is meant to complement and not replace clinical judgment, sonographic assessment, and visual cytopathology interpretation. • As molecular testing is new and advances in the field are regularly occurring, clinicians need to stay informed, as recommendations for use within practice are expected to evolve.

The role of core needle biopsy in the preoperative diagnosis of follicular neoplasm of the thyroid

Follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) can often be challenging to diagnose using core needle biopsy (CNB) specimens. We have developed the histologic criteria for the CNB diagnosis of FN and validated the usefulness of CNB. We retrospectively reviewed 184 CNBs and 224 FNACs diagnosed with FN/SFN. CNBs were histologically classified into four subgroups, based on the histologic features of follicular proliferation, fibrous capsulation, and surrounding parenchyma. Among 184 CNBs, 103 (55.9%) had previous FNAC results of non-diagnostic or indeterminate. Overall malignancy rates in FNAC (48%) and CNB (46%) were nearly identical (p>0.05), and the neoplasm rate was higher in CNB (88%) than FNAC (74%) (p=0.007). There was no significant difference in the malignancy rates among the four histologic subgroups. Among the 40 nodules with simultaneous CNB and FNAC, only nine had the FNAC diagnosis of FN/SFN, and others were non-diagnostic, benign, or atypia of undetermined significance. Overall, CNB improved specimen adequacy and achieved better sensitivity of the FN/SFN diagnosis in thyroid nodules that were inconclusive by FNAC. In the preoperative diagnosis of FN/SFN, CNB has no advantage over FNAC in predicting the likelihood of malignancy, but helps to reduce the need for repeat biopsy.

Improvement of the cytological diagnostic accuracy of follicular thyroid lesions by the use of the Ki‐67 proliferative index in addition to cytokeratin‐19 and HBME‐1 immunomarkers: a study of 61 cases of liquid‐based FNA cytology with histological controls

To evaluate HBME-1, cytokeratin-19 (CK-19) and Ki-67 immunomarkers in order to increase the diagnostic accuracy of preoperative thyroid fine needle aspiration (FNA) cytology. Immunocytochemistry against HBME-1, CK-19 and Ki-67 was performed on 123 thyroid FNAs processed by liquid-based cytology (LBC). Statistical analysis was carried out on 61 cases with histological control and sufficient material for one or more of the three markers. The Bethesda System was used for cytological diagnosis. Taking into account all the cytological categories, with a cut-off of 30% of positive cells, HBME-1 (n=47) and CK-19 (n=53) showed a sensitivity for malignancy of 66.7% (95% confidence interval, 53.2-80.1) and 90.5% (82.6-98.4) and a specificity of 90.6% (82.3-99) and 75% (63.3-86.7), respectively. For Ki-67 (n=54) with a cut-off of 1% of positive cells, the sensitivity was 85.0% (75.5-94.5) and the specificity 70.6% (58.4-82.7). In the follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) category (n=37), which was the focus of the study, papillary thyroid carcinomas (PTCs) were less numerous (four cases, three of which were the follicular variant), the positivity of the three immunomarkers combined showed an overall accuracy of 91% (21/23). The mean percentage of Ki-67-positive cells was increased in malignant lesions, with the exception of follicular variant PTCs: 16%±15.6% in two follicular carcinomas, 4.8%±3.2% in 13 classical PTCs, 1%±1.2% in five follicular variant PTCs and 0.5%±1.9% in 34 non-malignant lesions. Immunocytochemistry using HBME-1, CK-19 and the Ki-67 proliferative index increased the diagnostic accuracy of FNA in the FN/SFN category of the Bethesda System, which may help to distinguish lesions in this category with a low or high risk of malignancy. Thus, clinical management would be improved.

Hürthle cell presence alters the distribution and outcome of categories in the Bethesda system for reporting thyroid cytopathology

We aimed to determine whether the presence of Hürthle cells altered the distribution of categories in the Bethesda system for reporting thyroid cytopathology, or the expected neoplastic and malignant outcome. Fine needle aspiration (FNA) cytology reports of Hürthle cells in a 2-year period were evaluated. The distribution of Bethesda system categories and the outcome at partial or complete thyroidectomy were compared for FNAs with and without Hürthle cells. Of 895 adequate FNAs with Hürthle cells, 764 (85.4%) were classified as benign, 86 (9.6%) as atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 32 (3.6%) as follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), 12 (1.3%) as suspicious for malignancy (SFM) and one (0.1%) as malignant. Of 10359 adequate FNAs without Hürthle cells, 9707 (93.7%) were classified as benign, 412 (4.0%) as AUS/FLUS, 77 (0.7%) as FN/SFN, 93 (0.9%) as SFM and 70 (0.7%) as malignant. The distribution of categories in FNAs with and without Hürthle cells was significantly different (P<0.001) as a result of a decrease in benign and an increase in AUS/FLUS and FN/SFN categories. Among 128 patients with and 582 without Hürthle cells undergoing surgery, the overall neoplastic and malignancy rates were higher in the former than in the latter group (27.3% versus 14.9%, P<0.001; 21.1% versus 11.7%, P=0.003; respectively). Although neoplastic and malignant rates were higher in the group with than without Hürthle cells in all categories, the differences were only significant for a neoplastic outcome of benign cytology (15.1% versus 6.0%, P=0.0013) and a malignant outcome of FN/SFN cytology (63.6% versus 21.9%, P=0.0108). We found that the rates of AUS/FLUS and FN/SFN categories in the Bethesda system were higher when Hürthle cells were present. After surgery, neoplastic and malignant outcomes were significantly higher in the Hürthle cell group.

“Colloid‐Rich” follicular neoplasm/suspicious for follicular neoplasm thyroid fine‐needle aspiration specimens: Cytologic, histologic, and molecular basis for considering an alternate view

Typically, thyroid follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) cases show moderate to marked cellularity and scant or absent colloid. Recently, cases have been noted with microfollicular cellularity in the background of moderate to abundant amount of colloid. The purpose of this study was to compare these "colloid-rich" FN/SFN cases to the typical FN/SFN cases. Thyroid cytology specimens with the features of FN/SFN were searched in cytopathology files from September 2008 to June 2012. Cases with absent or minimal colloid were designated "typical colloid-poor" FN/SFN and cases with moderate to abundant colloid were designated "colloid-rich" FN/SFN. From these cases, those with surgical pathology resection follow-up were identified. Cytologic, surgical pathology resection, and molecular features (BRAF, RAS, RET/PTC, and PAX8-PPARγ) were investigated for the typical colloid-poor FN/SFN cases and were compared with those of the colloid-rich FN/SFN cases. Of 431 FN/SFN cases with surgical pathology resection follow-up, 360 (83.5%) cases showed features of typical colloid-poor FN/SFN and 71 (16.5%) cases showed features of colloid-rich FN/SFN. Papillary carcinoma was the most common malignant outcome for the 2 groups. Although the proportion of malignant outcome was similar for the 2 groups, the "colloid-rich" FN/SFN cases showed a greater proportion of nodular hyperplasia among the cases with benign outcome. In addition, the "colloid-rich" FN/SFN cases demonstrated a greater proportion of cases with a mutation. Approximately one-sixth of cases of FN/SFN show "colloid-rich" features. Comparison to the typical colloid-poor FN/SFN demonstrated similar risk for malignancy but contrasting resection outcome and molecular characteristics.

A histological assessment of the Bethesda system for reporting thyroid cytopathology (2010) abnormal categories: a series of 219 consecutive cases

The purposes of this study were to establish the distribution of thyroid lesions that were seen in Hatay (a province of southern Turkey), to review the accuracy of fine needle aspiration cytology (FNAC) in the diagnosis of thyroid nodules and to correlate the FNAC results with the histopathology of the excised specimens, especially in indeterminate cases. Data on patient cytology were retrieved by a retrospective search of all thyroid FNAC specimens that had been evaluated at the Department of Pathology, Antakya Public Hospital, Hatay, Turkey between January 2009 and February 2011; 1021 thyroid FNAC samples were reviewed and interpretations were recorded according to the Bethesda system for reporting thyroid cytopathology (TBSRTC). The results of adequate FNAC samples were compared with the histological diagnoses in the cases in which surgery was performed, and the malignancy rates, especially in indeterminate categories, were calculated. Of the 1021 FNAC samples, 697 (68.3%) were benign, 122 (11.9%) were non-diagnostic, 100 (9.8%) were atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 41 (4%) were follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), 36 (3.5%) were suspicious for malignancy (SM) and 25 (2.4%) were malignant. In 219 cases, there was follow-up histology. Rates of malignancy were as follows: benign, 0%; AUS/FLUS, 12.7%; FN/SFN, 35.0%; SM, 91.4%; malignant, 100%. In our study, the cytohistological correlation of benign and malignant lesions was 100%. In the indeterminate categories, we recommend that clinicians should evaluate both the clinical and radiological findings of patients in addition to the FNAC results.

Reproducibility of 'The Bethesda System for reporting Thyroid Cytopathology': A MultiCenter Study with Review of the Literature.

To achieve the standardization of the thyroid FNA reporting, the National Cancer Institute (NCI) hosted the "NCI Thyroid Fine Needle Aspiration State of the Science Conference", which led to the formation of 'The Bethesda System for Reporting Thyroid Cytopathology' (TBSRTC). The present study was undertaken by 2 experts in thyroid FNA, who in a double blinded fashion, examined and re-classified 80 random FNA cases according to the 6 levels of TBSRTC for an inter-observer review, to study and assess the new terminology for ease of reproducibility and to note the rate of disagreement overall or in any particular category. The FNAs were reclassified in a double blinded fashion according to the 6 levels of TBSRTC which are: non diagnostic (ND); benign; atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS); follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN), Hurthle cell type/suspicious for a follicular neoplasm, Hurthle cell type (FNHCT/SFNHCT); suspicious (SUS), and malignant. In the present study, the maximum number of cases was reclassified under the benign category (61.25% cases), followed by the FN/ SFN category and the AUS/FLUS category (11.25% and 10.00% respectively). An agreement was reached in 66 cases (82.5%); the experts disagreed in 14 cases-17.5% (where 1 expert did not agree with the other). Individually; a 93.87% agreement was noted for the lesions in the benign category, for 50% lesions in the AUS/FLUS category, for 66.66% lesions in the FN/SFN and the SUS categories, for 71.42% lesions in the FNHCT/ SFNHCT categories and for 100% lesions in the ND and the malignant categories. Thus, the maximum disagreement was noted in the AUS/FLUS category. The implementation of TBSTRC which stands for a unique, international and a universal terminology for reporting the thyroid cytology; should be encouraged in our country, because of its relative ease of reproducibility. Although there was a great deal of agreement in implementing TBSTRC in the present study; disagreements were seen in the categories of AUS/FLUS and FN/SFN in the study which was conducted at our centre. This corroborated with the findings of the studies which were done elsewhere.

The Impact of Thyroid Nodule Size on the Risk of Malignancy and Accuracy of Fine-Needle Aspiration: A 10-Year Study from a Single Institution

False-negative rates for thyroid fine-needle aspiration (FNA) vary from 0.4% to 13%, but the effect of nodule size on the accuracy of thyroid FNA remains controversial. We hypothesized that large thyroid nodule size does not contribute to the risk of malignancy or the risk of a false-negative FNA. All thyroid FNAs performed at the Walter Reed Army Medical Center during September 2001-August 2011 were reviewed. A strict correlation between the biopsy site, location, and size of nodule on ultrasound (US) and pathology report was ensured. FNA results were classified as benign, atypical, follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), suspicious for malignancy (SM), or malignant, and the pathology result was categorized as either benign or malignant. Nodules were analyzed by size: 0.5-0.9 cm (group A), 1.0-3.9 cm (group B), and ≥ 4 cm (group C). Incidental thyroid cancer was not included. Of 3013 patients undergoing FNA, 667 (22.1%) had surgery. Patients were excluded for nodules <0.5 cm, nondiagnostic FNA, or no preoperative US, leaving 540 patients with 695 nodules. Among patients referred for surgery, FNA results were benign in 417 nodules (60%), atypical in 22 (3.2%), FN/SFN in 122 (17.6%), SM in 77 (11.1%), and malignant in 57 (8.2%). Postoperative malignancy rates by FNA result were 7% if benign, 4.5% if atypical, 23% if FN/SFN, 33.8% if SM, and 78.9% if malignant. FNA accuracy was 60% in group A, 68.5% in group B, and 80.3% in group C (p=0.01). False-negative rates for FNA were 7.0% overall, 15.8% in group A, 6.3% in group B, and 7.1% in group C (p=0.25). Sensitivity and negative predictive value were highest in group B at 81.6% and 93.7%, respectively. The prevalence of malignancy was not different between groups. Our results show that the thyroid nodule size ≥ 4 cm increases neither the risk of false-negative FNA results, nor the overall risk of malignancy. We also show a tendency toward a higher false-negative rate in subcentimeter nodules. We conclude that a large nodule size should not prompt automatic referral for thyroidectomy. An increased awareness of potential sampling error in subcentimeter nodules is warranted.

The Bethesda Terminology for Reporting Thyroid Cytopathology: From Theory to Practice in Europe

Objectives: A 2007 conference held at the National Cancer Institute, Bethesda, Md., USA, proposed a new terminology for classifying the results of thyroid fine-needle aspiration (FNA) – The Bethesda System for Reporting Thyroid Cytology (TBSRTC). The need to standardize thyroid FNA terminology was emphasized during the 35th European Congress of Cytology in 2009. An interobserver review study to assess the new terminology for analyzing the results of thyroid FNA was organized by the scientific committee of the European Federation of Cytology Societies. Study Design: Four experts in thyroid FNA examined and classified 116 FNAs according to the 6 levels of TBSRTC which are: nondiagnostic (ND); benign; atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS); follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN), with those of Hürthle cell type reported as follicular neoplasm, Hürthle cell type/suspicious for a follicular neoplasm, Hürthle cell type (FNHCT/SFNHCT); suspicious (SUS), and malignant. Results: The total consensus was 62.1%; the cytopathologists disagreed on 44 cases, including 8 cases of AUS/FLUS and 18 of FN/SFN; 59% of the cases had no consensus. They agreed on 73 and 80% of the cases classified as benign and malignant, respectively, and on 58.3% of the SUS cases. The percentage of no consensus for each expert was between 32 and 39%. Conclusions: Disagreement regarding the use of TBSRTC terminology for classifying the results of thyroid FNA mainly occurred in the most-often criticized categories of AUS/FLUS and FN/SFN.