FNAC thyroid reporting categories: value of using the British Thyroid Association (Thy 1 to Thy 5) thyroid FNAC reporting guidelines

Rates of Thy 1-non-diagnostic thyroid fine needle aspiration using the UK Royal College of Pathologists Thy Terminology. A systematic review of the literature comparing patients who undergo rapid on-site evaluation and those who do not

INTRODUCTION

The UK Royal College of Pathologists (RCPath) Thy terminology is an internationally recognised system for reporting thyroid fine needle aspiration. The terminology has been used throughout the UK and Ireland, in some parts of Italy and Switzerland, and elsewhere in the world. There is no systematic review of the literature specifically addressing the use of the non-diagnostic for cytological diagnosis-Thy1/Thy 1c category in the UK RCPath terminology.

METHODS

A comprehensive literature search of online databases was conducted in October 2019 specifically examining overall reported rates of Thy1 and Thy1c in aspirates classified according to the UK Thy terminology.

RESULTS

Twenty-five articles were identified showing a Thy1 rate of 13.4% (2540/18 920). The studies were then stratified according to whether or not the patients underwent rapid on-site evaluation (ROSE): 6.0% (353/5841; range 3.0%-10.9%) of ROSE aspirates were Thy1 whereas 18.5% (2072/11 204; range 7.9%-43.3%) of non-ROSE patients were Thy1; (P < .05). Three studies from 2016 reported Thy1c rates of 5.4%, 6.5% and 10.6%, respectively, implying Thy1 rates excluding Thy1c aspirates of 20.9%, 8.7% and 12.7%, respectively.

CONCLUSION

This systematic review of the literature shows relatively high rates of aspirates non-diagnostic for cytological diagnosis-Thy1 in the peer-reviewed published literature using the UK terminology. Utilisation of ROSE appears to produce lower rates of Thy1 aspirates and ROSE should be considered if rates of non-diagnostic for cytological diagnosis-Thy1/Thy 1c are high.

Risk of malignancy in the various categories of the UK Royal College of Pathologists Thy terminology for thyroid FNA cytology: A systematic review and meta-analysis

BACKGROUND

The UK Royal College of Pathologists Thy terminology for reporting thyroid fine-needle aspiration cytology (FNAC), first published in 2009 is used throughout the United Kingdom and Ireland, in some parts of Italy and Switzerland and elsewhere. There is no review of the literature or meta-analysis of the risk of malignancy (ROM) in the various categories of the UK Thy terminology. The goal of this study was to establish the published ROM for each Thy category and compare the results with other existing terminology systems for which similar meta-analyses are available.

METHODS

A comprehensive literature search of online databases was conducted in May 2019 to examine the ROMs for histologically proven nodules with preoperative FNAC classified according to the UK Thy terminology.

RESULTS

Twenty-five articles were identified that showed results of both cytology and histology. Twelve of these articles were excluded to prevent a selection bias because they showed data in just 1 Thy category. In the remaining 13 articles, the pooled ROMs were as follows: Thy1, 12% (95% confidence interval [CI], 5%-22%); Thy2, 5% (95% CI, 3%-9%); Thy3, 22% (95% CI, 18%-26%); Thy3a, 25% (95% CI, 20%-31%); Thy3f, 31% (95% CI, 24%-39%); Thy4, 79% (95% CI, 70%-87%); and Thy5, 98% (95% CI, 97%-99%).

CONCLUSIONS

This meta-analysis shows results comparable to those of meta-analyses of other internationally recognized reporting terminologies for the pooled ROMs for surgically excised nodules in the various Thy reporting categories. There is comparatively little difference (only 6%) between the pooled ROMs of Thy3a and Thy3f surgically excised nodules.

Quality of Life in Patients Treated with Percutaneous Laser Ablation for Non-Functioning Benign Thyroid Nodules: A Prospective Single-Center Study

Objective

While many studies have reported that laser ablation (LA) for benign non-fuctioning thyroid nodules is efficacious in reducing nodular volume and neck symptoms, none have described changes in quality of life (QoL). The purpose of this study was to report post-LA changes in QoL in our cohort of patients.

Materials and Methods

Fourteen patients with benign thyroid nodules were involved in a prospective, single-center study and underwent a single session of LA. We evaluated the following: changes in nodule volume, thyroid function, and autoimmunity; adverse events during and after LA; changes in neck discomfort by means of a visual analogic scale (VAS) at one week and 1, 3, 6, and 12 months; and changes in QoL through the 13-scale Thyroid-specific Patient Reported Outcome (ThyPRO) questionnaire at 1, 3, 6, and 12 months. ThyPRO is a validated questionnaire for thyroid diseases, which consists of 13 scales with multiple-choice answers. They investigate several aspects of life that may be impaired by goiter-related compression symptoms, by esthetic alterations and by hypo- or hyperthyroidism.

Results

Nodule volume decrease was −37 ± 23%, −55 ± 22%, −53 ± 25%, −58 ± 25% (p < 0.01 vs. baseline) at the first, third, sixth, and twelfth month, respectively. No hypothyroidism or positivization of autoimmunity was observed. There were no major complications during or after LA. After LA, VAS scores improved significantly from 1 week onwards in 100% of patients, while a significant improvement was seen in the goiter symptoms score after one month, and in the general score and mean values of ThyPRO after six months. Scores on the other ThyPRO scales did not change significantly.

Conclusion

Laser ablation is safe and effective in reducing nodule volume and neck symptoms; this is confirmed by improvements in the goiter scale, general score, and mean values of ThyPRO and in the VAS score.

BRAFV600E mutation as a predictor of thyroid malignancy in indeterminate nodules: A systematic review and meta-analysis

BACKGROUND

Thyroid nodules are usually diagnosed using fine-needle aspiration (FNA). The sensitivity limitations of FNA result in 10-30% of nodules being classified as "indeterminate". The BRAF^V600E mutation is associated with papillary thyroid carcinoma (PTC). We conducted a systemic review and meta-analysis to evaluate the diagnostic utility of the BRAF^V600E mutation in indeterminate nodules.

METHOD

PUBMED and EMBASE were searched for studies testing for the BRAF^V600E involving indeterminate nodules (Thy3a, Thy3f, Thy4) and containing information on final surgical histopathology. Thirty two studies involving 3150 indeterminate nodules were included in the analysis.

RESULTS

The overall sensitivity and specificity for BRAF^V600E for the diagnosis of thyroid malignancy was 0.40 (95% CI: 0.32-0.48) and 1.00 (95% CI: 0.98-1.00) respectively. The diagnostic odds ratio (DOR) was 205.4 (95% CI: 40.1-1052). With a Fagan plot, the post-test probability of thyroid cancer, given a negative mutation was 6%, but this rose to 92% with a positive result. On subgroup analysis, for Thy3a nodules, the pooled sensitivity and specificity for thyroid malignancy was 0.21 (95% CI: 0.13-0.34) and 1.00 (95% CI: 0.98-1.00). For Thy3f nodules, the pooled sensitivity and specificity was 0.09 (95% CI: 0.03-0.20) and 1.00 (95% CI: 0.05-1.00) respectively. For Thy4 nodules, the corresponding sensitivity and specificity was 0.58 (95% CI: 0.5-0.64) and 0.99 (95% CI: 0.95-1.00) respectively.

CONCLUSIONS

Despite a high specificity for thyroid cancer, BRAF^V600E mutation has a low overall sensitivity and therefore has a limited diagnostic value as a single screening test.

Cytopathologic diagnosis of fine needle aspiration biopsies of thyroid nodules

Fine-needle aspiration (FNA) cytology is an important diagnostic tool in patients with thyroid lesions. Several systems have been proposed for the cyropathologic diagnosis of the thyroid nodules. However cases with indeterminate cytological findings still remain a matter of debate. In this review we analyze all literature regarding Thyroid Cytopathology Reporting systems trying to identify the most suitable methodology to use in clinical practice for the preoperative diagnosis of thyroid nodules. A review of the English literature was conducted, and data were analyzed and summarized and integrated from the authors’ perspective. The main purpose of thyroid FNA is to identify patients with higher risk for malignancy, and to prevent unnecessary surgeries for benign conditions. The Bethesda System for Reporting Thyroid Cytopathology is the most widely used system for the diagnosis of thyroid FNA specimens. This system also contains guidelines for the diagnosis and treatment of indeterminate or suspicious for malignancy cases. In conclusion, patients who require repeated FNAs for indeterminate diagnoses will be resolved by repeat FNA in a percentage of 72%-80%.

Parathyroid gland involvement by thyroid cancer: results from a large series of thyroidectomies performed in two italian university hospitals and review of the literature

Objectives.Parathyroid involvement by thyroid cancer (TC) has not been frequently investigated in thyroidectomy-based studies. We aimed to detect cases of parathyroid invasion by TC in a large series of thyroidectomies and to review the literature on this topic. Study Design. A 10-yr period database research was made from the files of the Section of Pathology of two Italian University Hospitals. Out of 22,310 thyroidectomies, 10 patients with parathyroid involvement by TC were found. Results. The 10 patients, 7 females and 3 males, aged 55 ± 14 years (range 34-76, median 56) had papillary thyroid carcinoma and accounted for 0.4% of subjects affected by all TCs and submitted to thyroidectomy. The tumor invaded perithyroid soft tissues in 6 patients and central neck (level VI) lymph nodes in 3. Parathyroid involvement by TC occurred by infiltration in 6 cases, extension through an intervening pseudocapsule in 1, and both patterns in 3. All patients are alive and disease free at 5.6 ± 3-yr follow-up. Conclusion. Limited to thyroidectomy series, our results and literature data suggest that parathyroid involvement by TC has a 0.4-3.9% incidence rate; mainly affects women in their sixth-seventh decade of life; is associated to a good prognosis, unless massive extrathyroid extension of TC occurs.

The role of 18F-fluorodeoxyglucose positron emission tomography in differentiated thyroid cancer before surgery

The incidence of thyroid cancer in both men and women is increasing faster than that of any other cancer. Although positron emission tomography (PET) using (18)F-fluorodeoxyglucose (FDG) has received much attention, the use of FDG PET for the management of thyroid cancer is limited primarily to postoperative follow-up. However, it might have a role in selected, more aggressive pathologies, and so patients at a high risk of distant metastasis may benefit from PET before surgery. As less FDG-avid thyroid cancers may lower the diagnostic accuracy of PET in preoperative assessment, an understanding of FDG avidity is important for the evaluation of thyroid cancer. FDG avidity has been shown to be associated with tumor size, lymph node metastasis, and glucose transporter expression and differentiation. As PET is commonly used in clinical practice, the detection of incidentalomas by PET is increasing. However, incidentalomas detected by PET have a high risk of malignancy. Clinicians handling cytologically indeterminate nodules face a dilemma regarding a procedure for a definitive diagnosis, usually lobectomy. With 'nondiagnostic (ND)' fine-needle biopsy (FNA), PET has shown a negative predictive value (NPV) of 100%, which indicates that negative uptake in a ND FNA procedure accurately excludes malignancy. With 'atypia of undetermined significance' or 'follicular neoplasm', the sensitivity and NPV of PET are 84 and 88%. PET does not provide additional information for the preoperative assessment of thyroid cancer. However, factors associated with FDG positivity are related to a poor prognosis; therefore, FDG PET scans before surgery may facilitate the prediction of the prognosis of differentiated thyroid cancer.

Comparison of 5-tiered and 6-tiered diagnostic systems for the reporting of thyroid cytopathology: a multi-institutional study

BACKGROUND

At present, thyroid fine-needle aspiration (FNA) specimens are diagnosed using a tiered classification scheme, with the most popular of these being the 5-tiered and 6-tiered systems. In this study, the authors present their institutional experiences using these 2 different systems and evaluate their efficacy based on the surgical follow-up.

METHODS

Thyroid FNA specimens and their corresponding surgical resection specimens were collected between 2007 and 2009. The following diagnostic categories are used in both systems: unsatisfactory/nondiagnostic, benign, follicular neoplasm/suspicious for follicular neoplasm, suspicious for malignancy, and malignant. An additional category termed atypia of undetermined significance/follicular lesion of undetermined significance was used for atypical cases in the 6-tiered system. Statistical analysis was performed by comparing the different diagnostic categories.

RESULTS

The case cohort included a total of 7686 thyroid FNA specimens representing 3962 nodules and 3724 nodules, respectively, in the 5-tiered and 6-tiered systems. Negative predictive values for the benign categories (96.9% vs 97.5%; P = 1) and positive predictive values for both the follicular neoplasm categories (26.5% vs 32.1%; P = .2531) and the malignant categories (99.1% vs 99.4%; P = 1) were similar. The most significant differences between the 5-tiered and 6-tiered systems were the percentage of cases classified as benign (83.9% vs 55.4%; P < .0001) and as follicular neoplasms (4.6% vs 23.8%; P < .0001). It is interesting to note that fewer patients were referred for surgery in the 5-tiered system compared with the 6-tiered one (9.1% vs 36.5%; P < .0001).

CONCLUSIONS

Use of either the 5-tiered or 6-tiered reporting systems for thyroid FNA specimens can potentially affect the clinical management of patients with thyroid nodules.

Immunocytochemistry with cytokeratin 19 and anti-human mesothelial cell antibody (HBME1) increases the diagnostic accuracy of thyroid fine-needle aspirations: preliminary report of 150 liquid-based fine-needle aspirations with histological control

BACKGROUND

Thyroid nodules are relatively common (7% of the population) but are malignant in only 5%-10% of cases. Fine-needle aspiration (FNA) to detect cancer can have > 90% sensitivity but only 50%-65% specificity because of false-positive results, which necessitates surgical controls. We aimed to assess the diagnostic accuracy of immunocytochemistry (ICC) of thyroid FNA to improve its sensitivity and specificity.

METHODS

We prospectively collected 2038 thyroid FNAs, of which 1397 were FNA biopsies with liquid-based cytology (Thin-Prep-Hologic®). ICC with cytokeratin 19 and HBME1 antibodies (Dako® A/S) was used for all malignant cases and cases of atypical cells of undetermined significance (AUS), follicular neoplasm (FN), and nodules suspicious for malignancy-papillary thyroid carcinoma (SM-PTC) as well as some benign cases (abnormal features on radiography or benign on secondary FNA). ICC results were defined as "non-contributory," "favoring benign," "favoring malignant," or "indeterminate." Results for 150 cases were compared with histological controls for diagnostic accuracy.

RESULTS

Of these 150 cases ICC was helpful for benign or malignant triage of 48 cases of AUS, FN, and SM-PTC (42% of these lesions). Six (4%) ICC results were false positive (favoring malignant with benign histology) but none were false negative (favoring benign with malignant histology). Results for indeterminate cytological cases favored malignant or benign disease with sensitivity, specificity, and negative and positive predictive values of 100%, 85.2%, 100%, and 86.2%, respectively.

CONCLUSIONS

ICC of thyroid FNAs with cytokeratin 19 and HBME1 antibodies can reduce the false-positive and false-negative results of single morphological analyses. It can increase the sensitivity and specificity of diagnosis, thus improving diagnostic accuracy and reducing the need for surgical controls.

The interobserver reproducibility of thyroid fine-needle aspiration using the UK Royal College of Pathologists' classification system

The overall interobserver reproducibility of thyroid fine-needle aspiration (FNA) has not been comprehensively assessed. A blinded 6-rater interobserver reproducibility study was conducted of 200 thyroid FNA cases using the UK System, which is similar to The Bethesda System for Reporting Thyroid Cytology: Thy1, nondiagnostic; Thy2, nonneoplastic; Thy3a, atypia, probably benign; Thy3f, follicular lesion; Thy4, suspicious of malignancy; and Thy5, malignant. There was good interobserver agreement for the Thy1 (κ = 0.69) and Thy5 (κ = 0.61), moderate agreement for Thy2 (κ = 0.55) and Thy3f (κ = 0.51), and poor agreement for Thy3a (κ = 0.11) and Thy4 (κ = 0.17) categories. Combining categories implying surgical management (Thy3f, Thy4, and Thy5) achieved good agreement (κ = 0.72), as did combining categories implying medical management (Thy1, Thy2, and Thy3a; κ = 0.72). The UK thyroid FNA terminology is a reproducible and clinically relevant system for thyroid FNA reporting. This study demonstrates that international efforts to harmonize and refine thyroid cytology classification systems can improve consistency in the clinical management of thyroid nodules.

Can misdiagnosis in pre-operative FNAC of thyroid nodule influence surgical treatment?

BACKGROUND

Pre-operative cytology in thyroid disease remains the most appropriate diagnostic test for defining the nature of a thyroid nodule before surgical excision.

MATERIALS AND METHODS

We selected the most recent 825 surgical thyroid procedures performed in our institution from January 2004 to June 2007; 776 were total thyroidectomies, 23 were lobe-isthmectomies, and 26 were radical neck dissections. We distributed the data based on pre-operative cytology. Each cytological diagnosis was compared to results obtained by definitive histology. Tumors were called incidentalomas if they consisted of a neoplastic focus with a low grade of aggressiveness, as demonstrated by dimension <5 mm, non-aggressive histological subtype.

RESULTS

Of the 541 cases of benign disease, 417 were confirmed as benign. The other 124 cases are listed as follows: 29 follicular adenoma; 76 papillary carcinoma (35 found as incidentalomas), and 19 follicular carcinoma (3 incidentalomas). Cytology suggestive of papillary carcinoma was correct in 95.2% of cases (119/125). The 135 tumors termed "follicular neoplasm" were staged on pathology thus: 56 adenoma (41.4%), 26 carcinoma (19.2%), 13 (9.6%) absence of follicular proliferation, 38 (28.1%) papillary follicular variant, 2 (1.4%) undifferentiated cells. Medullary carcinomas were both confirmed. The "suspicious group" exhibited no malignancy on fine needle aspiration cytology (12 of 21; 57%).

CONCLUSIONS

Cytology has good reliability in malignant lesions. Incidental tumors occurring in benign disease have little impact on clinical and surgical management; "follicular neoplasm" posed two problems - the impossibility of identifying the nature of the tumor, as well as the newer difficulty in distinguishing papillary follicular subtype.