Molecular pathology and thyroid FNA

Deep learning models for thyroid nodules diagnosis of fine-needle aspiration biopsy: a retrospective, prospective, multicentre study in China

BACKGROUND

Accurately distinguishing between malignant and benign thyroid nodules through fine-needle aspiration cytopathology is crucial for appropriate therapeutic intervention. However, cytopathologic diagnosis is time consuming and hindered by the shortage of experienced cytopathologists. Reliable assistive tools could improve cytopathologic diagnosis efficiency and accuracy. We aimed to develop and test an artificial intelligence (AI)-assistive system for thyroid cytopathologic diagnosis according to the Thyroid Bethesda Reporting System.

METHODS

11 254 whole-slide images (WSIs) from 4037 patients were used to train deep learning models. Among the selected WSIs, cell level was manually annotated by cytopathologists according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) guidelines of the second edition (2017 version). A retrospective dataset of 5638 WSIs of 2914 patients from four medical centres was used for validation. 469 patients were recruited for the prospective study of the performance of AI models and their 537 thyroid nodule samples were used. Cohorts for training and validation were enrolled between Jan 1, 2016, and Aug 1, 2022, and the prospective dataset was recruited between Aug 1, 2022, and Jan 1, 2023. The performance of our AI models was estimated as the area under the receiver operating characteristic (AUROC), sensitivity, specificity, accuracy, positive predictive value, and negative predictive value. The primary outcomes were the prediction sensitivity and specificity of the model to assist cyto-diagnosis of thyroid nodules.

FINDINGS

The AUROC of TBSRTC III+ (which distinguishes benign from TBSRTC classes III, IV, V, and VI) was 0·930 (95% CI 0·921-0·939) for Sun Yat-sen Memorial Hospital of Sun Yat-sen University (SYSMH) internal validation and 0·944 (0·929 - 0·959), 0·939 (0·924-0·955), 0·971 (0·938-1·000) for The First People's Hospital of Foshan (FPHF), Sichuan Cancer Hospital & Institute (SCHI), and The Third Affiliated Hospital of Guangzhou Medical University (TAHGMU) medical centres, respectively. The AUROC of TBSRTC V+ (which distinguishes benign from TBSRTC classes V and VI) was 0·990 (95% CI 0·986-0·995) for SYSMH internal validation and 0·988 (0·980-0·995), 0·965 (0·953-0·977), and 0·991 (0·972-1·000) for FPHF, SCHI, and TAHGMU medical centres, respectively. For the prospective study at SYSMH, the AUROC of TBSRTC III+ and TBSRTC V+ was 0·977 and 0·981, respectively. With the assistance of AI, the specificity of junior cytopathologists was boosted from 0·887 (95% CI 0·8440-0·922) to 0·993 (0·974-0·999) and the accuracy was improved from 0·877 (0·846-0·904) to 0·948 (0·926-0·965). 186 atypia of undetermined significance samples from 186 patients with BRAF mutation information were collected; 43 of them harbour the BRAFV600E mutation. 91% (39/43) of BRAFV600E-positive atypia of undetermined significance samples were identified as malignant by the AI models.

INTERPRETATION

In this study, we developed an AI-assisted model named the Thyroid Patch-Oriented WSI Ensemble Recognition (ThyroPower) system, which facilitates rapid and robust cyto-diagnosis of thyroid nodules, potentially enhancing the diagnostic capabilities of cytopathologists. Moreover, it serves as a potential solution to mitigate the scarcity of cytopathologists.

FUNDING

Guangdong Science and Technology Department.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Age and BRAFV600E Mutation Stratified Patients with Cytologically Benign Thyroid Nodules

Purpose

Our objective was to evaluate the diagnostic performance of BRAFV600E mutation for malignant, and to identify clinical characteristics associated with positive BRAFV600E mutation in low-risk cytological and ultrasound diagnostic thyroid nodules. This aims to identify patients who may benefit from BRAFV600E mutation testing and subsequent surgical intervention.

Patients and Methods

We analysis the clinical characteristics correlated with BRAFV600E mutation in our detection cohort, including 204 patients with 217 thyroid nodules, and separate analyses were performed in 103 thyroid nodules with benign cytological result. Signaling pathway and immune response associated with age and BRAFV600E mutation status were also evaluated in Asian patients with thyroid cancer from the Cancer Genome Atlas (TCGA) dataset.

Results

The positive BRAFV600E mutation was significantly associated with higher Ultrasound (US) classification (p<0.001) and fine-needle aspiration (FNA) categories (p<0.001). BRAFV600E mutation as a risk factor for malignancy, showing the optimal diagnostic efficacy for malignancy combined with FNA categories, with the AUC was 0.923. Otherwise, BRAFV600E mutation is a risk factor in screening malignancy in low-risk FNA and US classification, which is significant correlation with patients age. Patients over 50 years old exhibiting a higher percentage of positive BRAFV600E mutation when both ultrasound and FNA results indicate benign conditions, with higher risk of malignancy.

Conclusion

BRAFV600E mutation is an accurate adjunctive diagnostic marker on FNA to screen malignancy. In low risk of both ultrasound and FNA results, the positive BRAFV600E was significant increased in patients over 50 years old, which have higher risk of malignancy. Thus, the BRAFV600E mutation detection and further surgery should be strengthened in older patients with benign cytological and US results thyroid nodules.

Genetic Considerations in the Tumorigenesis, Diagnosis, and Treatment of Differentiated Thyroid Cancer: Current State of the Science

Thyroid nodules remain a common diagnosis encountered in general and endocrine surgical practice, and thyroid cancer appears to be increasing in incidence in both the United States and worldwide. The understanding of the complex genetics surrounding thyroid neoplasia has increased substantially in recent years and, consequently, has become a consideration in risk stratification, diagnosis, prognosis, and treatment. Molecular genetic analysis of thyroid nodules is now a readily available technology for diagnostic purposes via analysis of fine-needle aspiration biopsy (FNAB) specimens. Although their routine use is controversial, they may aid in selecting which patients require surgery and those who may be safely observed. In the following review, the genetics of the tumorigenesis of thyroid cancer are reviewed, focusing on the most common and clinically relevant of the literally hundreds of known mutations. Following this, the current status of the use of genetic analysis and molecular diagnostics in the workup of thyroid nodules and the diagnosis of differentiated thyroid cancer is explored. Finally, evolving concepts relating to the use of thyroid cancer genetics in individualizing treatment planning, follow-up, and management of recurrent disease is discussed. The goal is to provide the general surgeon with a working knowledge of the most common genetic alterations present in differentiated thyroid cancer, their relevance in clinical practice, and how they impact prognosis and treatment.

Detecting Somatic Mutations for Well-Differentiated Pancreatic Neuroendocrine Tumors in Endoscopic Ultrasound-Guided Fine Needle Aspiration with Next-Generation Sequencing

BACKGROUND

Pancreatic neuroendocrine tumors (PanNETs) exhibit heterogenous behavior, whereby some small tumors are aggressive with a propensity for metastasis. Detection of somatic mutations associated with aggressive biology may help with patient stratification and surgical decision-making in patients with well-differentiated PanNETs. Using next-generation sequencing (NGS), we investigated the feasibility of detecting somatic mutations in endoscopic ultrasound-guided, fine-needle aspiration (EUS-FNA) specimens and determining the mutational concordance between the EUS-FNA specimens and the primary tumors.

METHODS

Thirty-eight patients with well-differentiated, nonfunctioning PanNETs were obtained from two tertiary referral centers. Patient demographic characteristics and tumor, clinicopathologic features were collected. Tissue from both the EUS-FNA specimen and the primary tumor was extracted from archival tissue blocks. NGS using a panel of ten genes was performed on both samples.

RESULTS

In our series, the median age was 61.1 years. Tumors were predominantly left-sided (60.5%) and unifocal (94.7%). The median tumor size was 2.2 cm. NGS detected somatic mutations in 29% of primary tumors and 36.8% of EUS-FNA specimens. In primary tumors, DAXX/ATRX mutations were predominantly detected (63.6%). In EUS-FNA specimens, MEN1 mutations were predominantly detected (64.3%). Among non-wild-type specimens, mutational concordance was achieved in 31.6% of cases. In 11 patients with a detectable mutation in the primary tumor, a mutation was detected in the EUS-FNA specimen in 45.5% of cases, with a mutational concordance of 54.5%.

CONCLUSIONS

NGS can detect somatic mutations in EUS-FNA specimens of well-differentiated PanNETs. Efforts to improve detection sensitivity and mutational concordance are required to overcome current technical limitations.

Mixed medullary‑follicular thyroid carcinoma: A case report and literature review

Papillary thyroid cancer (PTC) and medullary thyroid cancer (MTC) originate from follicular and neuroendocrine parafollicular C cells, respectively. PTC and MTC simultaneously exist in tumors containing both MTC and PTC features in a rare condition known as mixed medullary-follicular thyroid carcinoma (MMFTC). In the present study, a 60-year-old female presented with a small mass on the left side of the neck. Ultrasonography indicated a hyperechoic nodule measuring ~11.9×9.7 mm2 in the left lobe of the thyroid gland. The preoperative calcitonin serum value was elevated and total thyroidectomy and bilateral central compartment lymph node dissection was performed. Histological and immunohistochemical analysis of the tumor demonstrated MMFTC. No metastasis was observed in lymph nodes isolated from the bilateral central compartment. Given the rarity of MMFTC, enhancing understanding and management of such tumors is crucial.

Performance of multigene testing in cytologically indeterminate thyroid nodules and molecular risk stratification

Objective

Thyroid cancer is the third most prevalent cancer among females. Genetic testing based on next-generation sequencing may provide an auxiliary diagnosis to reduce cytologically diagnostic uncertainty. However, commercial multigene tests are not widely available and are not well-tested in the Chinese population.

Methods

In this study, we designed a multigene testing panel and evaluated its performance in 529 cytologically indeterminate thyroid nodules (Bethesda III, IV and V). The molecular data of the DNA mutations and RNA fusions of fine needle aspiration samples were reviewed in conjunction with a clinical diagnosis, pathological reports, and definitive surgery for retrospective analysis. Then, the molecular risk stratification was investigated for its accuracy in malignant risk prediction.

Results

The overall combined consistency revealed substantial agreement (Kappa = 0.726) with the sensitivity, specificity, positive predictive value, and negative predictive values of 97.80%, 82.14%, 98.99%, and 67.65%, respectively. The most common aberration was BRAFV600E (82.59%), followed by NRAS mutants (4.07%), RET fusions (3.70%), and KRAS mutants (3.15%). Two cases (0.44%) were categorized into a high-risk group, 426 cases (94.67%) were categorized into a BRAF-like group with totally histopathologic papillary patterned tumors, and 22 cases (4.89%) were categorized into a RAS-like group with 14 papillary and eight follicular patterned tumors when the cohort concurrent aberrations were excluded. Potentially aggressive features may be related to concurrent molecular alterations of BRAFV600E with TERTQ302R, and AKT1L52R, NRASG12C, NRASQ61R, and CCDC6-RET fusions.

Conclusions

This study provided a multigene panel for identifying benign nodules from cytologically indeterminate thyroid nodules to avoid unnecessary surgery. We provide further evidence for using molecular risk stratification as a promising predictor of disease outcomes. The results of this study may be limited by the extremely high prevalence of cancer in the cohort for clinical reference.

Immunomorphological Patterns of Chaperone System Components in Rare Thyroid Tumors with Promise as Biomarkers for Differential Diagnosis and Providing Clues on Molecular Mechanisms of Carcinogenesis

Hurthle cell (HC), anaplastic (AC), and medullary (MC) carcinomas are low frequency thyroid tumors that pose several challenges for physicians and pathologists due to the scarcity of cases, information, and histopathological images, especially in the many areas around the world in which sophisticated molecular and genetic diagnostic facilities are unavailable. It is, therefore, cogent to provide tools for microscopists to achieve accurate diagnosis, such as histopathological images with reliable biomarkers, which can help them to reach a differential diagnosis. We are investigating whether components of the chaperone system (CS), such as the molecular chaperones, can be considered dependable biomarkers, whose levels and distribution inside and outside cells in the tumor tissue could present a distinctive histopathological pattern for each tumor type. Here, we report data on the chaperones Hsp27, Hsp60, and Hsp90. They presented quantitative levels and distribution patterns that were different for each tumor and differed from those of a benign thyroid pathology, goiter (BG). Therefore, the reported methodology can be beneficial when the microscopist must differentiate between HC, AC, MC, and BG.

Preoperative BRAFV600E mutation detection in thyroid carcinoma by immunocytochemistry

The BRAF^V600E (BRAF) mutation is present in 40-50% of papillary thyroid carcinomas (PTC) and has been associated with more aggressive clinicopathological characteristics of PTC. The aim of this study was to evaluate different methods for preoperative identification of the BRAF mutation in PTC using cytological and histological specimens. Prospectively collected preoperative cytological clots from patients with suspected PTC were tested with BRAF immunocytochemistry (ICC) and the Cobas Test (PCR). In addition, histological specimens were tested with BRAF immunohistochemistry (IHC) and the Cobas Test. All nodules were histologically examined. Fifty-three patients were included in the study. Complete mutation testing was available in 32 patients. The main reason for exclusion was insufficient cell content in the cytological specimen. Twenty-seven nodules were histologically diagnosed as PTC, and 41% (n = 11) of PTCs were BRAF ICC positive. All non-PTC nodules were negative by BRAF ICC. In 26 nodules, all four BRAF tests were concordant, while discordant test results were found in six nodules. ICC was in accordance with the consensus BRAF status in five of these nodules, while BRAF status was undetermined in one nodule. BRAF ICC showed high concordance with the Cobas Test and a low rate of false negative stain. These results indicate that BRAF ICC may be a feasible method for preoperative detection of the BRAF^V600E mutation in patients with PTC.

Construction and validation of BRAF mutation diagnostic model based on ultrasound examination and clinical features of patients with thyroid nodules

Introduction: Fine Needle Aspiration (FNA) is currently the most popular method for identifying benign and malignant thyroid nodules. However, its diagnostic sensitivity is sometimes limited, which makes it necessary to apply genetic testing and other modalities as a secondary diagnostic method. The diagnostic accuracy of thyroid nodule can be improved by combining mutations in the B-Raf proto-oncogene serine/threonine kinase (BRAF) with FNA. Thus, this study was conducted to create a nomogram diagnostic model based on the clinical and ultrasonic characteristics of patients with BRAF mutations to aid in the identification of benign and malignant thyroid nodules using FNA.

Methods: From April 2018 to December 2021, 275 patients with thyroid nodules who underwent ultrasonography and BRAF gene testing (137 positive and 138 negative) were included from Xianyang Central Hospital. The clinical and ultrasonic characteristics of the patients were used to develop a nomographic, diagnostic model of BRAF gene mutation, and to validate and evaluate the usefulness of the model.

Results: Independent risk factors for BRAF mutations included: focal strong echogenicity (microcalcifications, OR = 3.04, 95%CI = 1.41–6.58, p = 0.005), hypoechogenicity (OR = 3.8, 95%CI = 1.14–12.61, p = 0.029), lymph node metastases (OR = 3.54, 95%CI = 1.43–8.75, p = 0.006), margin (lobulated, OR = 3.7, 95%CI = 1.66–8.23, p = 0.001; extrathyroidal invasion, OR = 2.81, 95%CI = 1.11–7.06, p = 0.029), and shape (vertical position, OR = 2.7, 95%CI = 1.11–6.59, p = 0.029). The area under the curve (AUC) of the receiver operating characteristic (ROC) curve of the BRAF mutation diagnostic model constructed on these factors was 0.806 (95% CI = 0.754–0.851), and 39.5% was set as the threshold probability of making a clinical decision. The results of the validation and clinical utility evaluation showed that our model had good predictive performance and clinical application value.

Conclusion: Our nomogram diagnostic model based on clinical and ultrasound features of patients accurately predicted the possibility of BRAF gene mutations in patients with thyroid nodules.

Molecular Pathological Diagnosis of Thyroid Tumors Using Spatially Resolved Metabolomics

The pathological diagnosis of benign and malignant follicular thyroid tumors remains a major challenge using the current histopathological technique. To improve diagnosis accuracy, spatially resolved metabolomics analysis based on air flow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) technique was used to establish a molecular diagnostic strategy for discriminating four pathological types of thyroid tumor. Without any specific labels, numerous metabolite features with their spatial distribution information can be acquired by AFADESI-MSI. The underlying metabolic heterogeneity can be visualized in line with the cellular heterogeneity in native tumor tissue. Through micro-regional feature extraction and in situ metabolomics analysis, three sets of metabolic biomarkers for the visual discrimination of benign follicular adenoma and differentiated thyroid carcinomas were discovered. Additionally, the automated prediction of tumor foci was supported by a diagnostic model based on the metabolic profile of 65 thyroid nodules. The model prediction accuracy was 83.3% when a test set of 12 independent samples was used. This diagnostic strategy presents a new way of performing in situ pathological examinations using small molecular biomarkers and provides a model diagnosis for clinically indeterminate thyroid tumor cases.

Clinical value of FNA puncture feeling in the diagnosis of non-diagnostic and indeterminate thyroid nodules

OBJECTIVE

The aim of this study was to explore the clinical diagnostic value of puncture feeling during fine-needle aspiration (FNA) for non-diagnostic and indeterminate thyroid nodules.

METHODS

A retrospective analysis was performed on 176 patients (196 nodules) diagnosed with Bethesda I or III by FNA cytology at the ultrasound department of our hospital between January 2017 and January 2020. Comparisons were made on the differences in puncture feeling (including stiffness and grittiness) between benign and malignant thyroid nodules, and their diagnostic performance was analyzed.

RESULTS

There were significant differences between benign and malignant nodules with respect to the puncture stiffness and puncture grittiness (P < 0.001). The presence of a hard stiffness and grittiness demonstrated comparable levels of diagnostic performance for malignant thyroid nodules, with sensitivities, specificities, accuracies, positive predictive values, and negative predicative values of 55.56% and 63.89%, 87.10% and 78.22%, 75.51% and 72.96%, 71.43% and 63.01%, and 77.14% and 78.86%, respectively. The diagnostic performance was most optimal in the presence of at least one puncture feeling (area under the receiver operating characteristic curve: 0.771), exhibiting a sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of 79.17%, 75.00%, 76.53%, 64.77, and 86.11%%, respectively.

CONCLUSIONS

Puncture feeling adds clinical value in the diagnosis of thyroid nodules with indeterminate FNA findings.

Risk Factors for Neck Nodal Metastasis in Papillary Thyroid Cancer With BRAF V600E Mutation

BACKGROUND

The BRAF V600E mutation is the most common genetic variant in papillary thyroid cancer (PTC), but the relationship between the BRAF V600E mutation in PTC and cervical lymph node metastasis (LNM) remains controversial.

OBJECTIVE

To estimate risk factors for neck nodal metastasis in PTC with BRAF V600E mutation.

PATIENTS

A total of 292 patients diagnosed with BRAF V600E mutation related PTC were admitted.

DESIGN

In this retrospective study, data from 292 patients, including clinical, molecular, and ultrasonic characteristics, were analyzed. Univariate and multivariate logistic regression analyses were applied to identify risk factors for LNM in PTC with the BRAF V600E mutation.

RESULTS

In the univariate analysis of all PTC patients with the BRAF V600E mutation, the LNM was found to be significantly associated with age (P = 0.010), size (P = 0.000), bilaterality (P = 0.000), multifocality (P = 0.002), LNM in ultrasound (US) (P = 0.000), and capsular invasion (P = 0.010). In ultrasonic image characteristics, margin (P = 0.036), shape (P = 0.046), and microcalcification (P = 0.002) were significantly associated with LNM. In multivariate analysis, LNM in PTCs with BRAF V600E mutation was significantly associated with age ≤ 45 years (OR = 1.869, P = 0.020, 95% CI = 1.106 - 3.158), size ≥ 1cm (OR = 3.131, P = 0.001, 95% CI = 1.578 - 6.212), LNM in US (OR = 6.962, P = 0.000, 95% CI = 2.924 - 16.572), bilaterality (OR = 1.626, P = 0.007, 95% CI = 1.142 - 2.314), ill-defined margins in US (OR = 1.980, P = 0.033, 95% CI = 1.057 - 3.709), and microcalcification in US (OR = 2.786, P = 0.002, 95% CI = 1.464 - 5.303).

CONCLUSION

This study revealed that several significant risk factors for LNM in PTCs with the BRAF V600E mutation included: age ≤ 45 years, size ≥ 1cm, LNM in US, bilaterality, ill-defined margins in US, and microcalcification in US.

Molecular Characterization of Thyroid Follicular Lesions in the Era of "Next-Generation" Techniques

It is unequivocally recognized that thyroid nodules are frequently detected in the adult population and mostly characterized by benign lesions (up to 70% of them), with only 5%-15% malignant lesions. The evaluation of thyroid lesions with fine-needle aspiration cytology (FNAC) represents one of the first and most useful diagnostic tools in the definition of their nature. Despite the fact that the majority of thyroid lesions are correctly diagnosed as either benign (70%-75%) or malignant (5%-10%) entities, the remaining nodules (20%-25%) represent the "gray zone" of follicular lesions, which belong to indeterminate categories, according to the different classification systems. This indeterminate group of lesions includes both benign and malignant entities, which cannot be easily discriminate with morphology alone. In these last decades, the increasing role of molecular testings, feasibly performed on cytological material combined with the discoveries of specific genetic alterations in the field of thyroid pathology, has opened the pace to their more accurate and specific contribution on cytology. In fact, in 2015, in the revised management guidelines for patients with thyroid nodules and well-differentiated thyroid cancers (WDTCs), the American Thyroid Association (ATA) confirmed the performance of molecular testing in thyroid indeterminate cytology, and the same performance was addressed in recent update of the management of thyroid nodules in the second edition of the Bethesda system for reporting thyroid cytopathology (TBSRTC). In the current review, we discuss the role of molecular tests for the different thyroid diagnostic categories of the Bethesda system for reporting thyroid cytopathology, mostly focusing our attention on the follicular and indeterminate lesions.

Advances in Biomarker-Driven Targeted Therapies in Thyroid Cancer

Simple Summary

This article reviews current treatment practices for thyroid cancer with a focus on novel targeted molecular therapy. Rapidly expanding knowledge of the molecular biology of these cancers coupled with the increased availability of genetic testing has led to exciting paradigm shifts in treatment strategies for these tumor types. We aim to provide up-to-date information on these state-of-the-art therapies as a guide for clinicians who specialize in the treatments of thyroid cancer.

Abstract

Thyroid cancer is the most common type of endocrine malignancy comprising 2–3% of all cancers, with a constant rise in the incidence rate. The standard first-line treatments for thyroid cancer include surgery and radioactive iodine ablation, and a majority of patients show a good response to these therapies. Despite a better response and outcome, approximately twenty percent of patients develop disease recurrence and distant metastasis. With improved knowledge of molecular dysregulation and biological characteristics of thyroid cancer, the development of new treatment strategies comprising novel targets has accelerated. Biomarker-driven targeted therapies have now emerged as a trend for personalized treatments in patients with advanced cancers, and several multiple receptor kinase inhibitors have entered clinical trials (phase I/II/III) to evaluate their safety and efficacy. Most extensively investigated and clinically approved targeted therapies in thyroid cancer include the tyrosine receptor kinase inhibitors that target antiangiogenic markers, BRAF mutation, PI3K/AKT, and MAPK pathway components. In this review, we focus on the current advances in targeted mono- and combination therapies for various types of thyroid cancer.

Fine-needle Aspiration Washout Precipitation Specimens: An Acceptable Supplement to Genetic Mutation Detection of Thyroid Nodules

Objectives: Thyroid nodules are common in adults, but only some of them are malignant. Ultrasound-guided fine-needle aspiration (FNA) is widely applied as a reliable and minimally invasive technique for evaluating thyroid nodules. However, the scarcity of FNA biopsy specimens poses a challenge to molecular diagnosis. This study aimed to evaluate the feasibility of FNA washout precipitation specimens as an effective supplement to the thyroid genetic test. Methods: A total of 115 patients with thyroid nodules were enrolled in our study. The BRAF V600E mutation status was detected in all FNA washout precipitation specimens and biopsy formalin-fixed paraffin-embedded (FFPE) specimens using an amplification refractory mutation system PCR (ARMS-PCR). All patients underwent cytological diagnoses; 79 patients also underwent surgery for histopathological analysis. Results: All the 115 samples were successfully analyzed using both FNA washout precipitation and biopsy FFPE specimens. The results showed that the BRAF V600E status detected in 96 FNA washout precipitation specimens were consistent with that in FNA biopsy FFPE specimens, including 41 BRAF V600E positive and 55 BRAF V600E negative, achieving a concordance rate of 84.4% (kappa  =  0.689). Furthermore, the BRAF V600E mutation status using FNA washout precipitation specimens provided a 100.0% positive predictive value for diagnosing papillary thyroid carcinoma in patients with The Bethesda system for reporting thyroid cytopathology (TBSRTC) V. Besides, the BRAF V600E mutation status was positive in 90.9% (10/11) FNA washout precipitation specimens from patients with capsule invasion, achieving a higher overall sensitivity of 100.0%, compared with 57.1% of FNA washout precipitation specimens from patients without capsule invasion. Conclusion: These results suggested that FNA washout precipitation specimens might be a valuable supplementary sample type for detecting the BRAF V600E mutation in patients with thyroid nodules, especially with thyroid capsule invasion.

Rapid identification of papillary thyroid carcinoma and papillary microcarcinoma based on serum Raman spectroscopy combined with machine learning models

Thyroid carcinoma is one kind of cancer with the highest diagnosis rate in the endocrine system, and its main histological subtype is papillary thyroid carcinoma (PTC) accounting for 80% of thyroid malignancies. In recent years, the incidence of thyroid cancer has increased exponentially, and its substantial increase was closely related to the overdiagnosis of papillary microcarcinoma (PMC). Therefore, early and accurate identification of PTC and PMC can prevent patients from being irreversibly damaged. This study aimed to identify PTC and PMC using Raman spectroscopy. We collected serum Raman spectra from 16 patients with PTC and 31 patients with PMC. Firstly, the collected imbalance data were preprocessed using the synthetic minority over-sampling technique (SMOTE). Then, the equalized data were dimensionality reduced by principal component analysis (PCA). Finally, the processed data were fed into the single decision tree (DT) classifier, as well as the random forest (RF) built on the idea of Boosting ensemble and the Adaptive Boosting (Adaboost) model built on the idea of Bagging ensemble for classification. The classification accuracy of the three models in the testing set were 75.38%, 81.54%, and 84.61%, respectively. Compared with the DT classifier, the accuracy of the models introducing the idea of ensemble learning was enhanced by 6.16% and 9.23%, respectively. The best model was the Adaboost. This result demonstrates that serum Raman spectroscopy combined with an ensemble learning algorithm was feasible in rapidly identifying PTC and PMC. At the same time, the method has great potential for application in the field of clinical diagnosis.

Fine-needle aspiration cytology of an intrathyroidal nodule diagnosed as squamous cell carcinoma: A case report

BACKGROUND

Both squamous cell carcinoma (SCC) and papillary thyroid carcinoma (PTC) are common malignant tumors in the neck. However, seldom has SCC of the thyroid been diagnosed. Further, cytological features of SCC and PTC have rarely been reported. The significance of fine-needle aspiration cytology (FNAC) in the diagnosis of neck masses has been established. Herein, we present an exceedingly rare case of an intrathyroidal SCC diagnosed using FNAC, along with its cytological features.

CASE SUMMARY

A 66-year-old man presented with a left-sided neck mass. Ultrasound examination showed an ill-defined nodule. The appearance was hypoechoic with a few hyperechoic spots. FNAC of the left thyroid nodule was performed. A cellular smear was obtained, and it showed a large number of neoplastic cells with rich cytoplasm and poor cell adhesion. Tumor cell nuclei showed coarse nuclear chromatin and a few enlarged prominent nucleoli. An increased nuclear/cytoplasm ratio was observed. Thus, malignancy was diagnosed without a confirmed tumor type. Percutaneous tumor biopsy was performed to make a definite diagnosis. The tumor cells showed typical squamous cell characteristics.

CONCLUSION

Head and neck SCC and PTC have different cytologies. Measures are needed to ensure accurate diagnosis using FNAC.

Gene Mutation Analysis in Papillary Thyroid Carcinoma Using a Multi-Gene Panel in China

Purpose

To detect low-frequency mutation in the 57 genes of small panels that are associated with developing thyroid cancer in papillary thyroid carcinoma (PTC) patients and provide patients with precise-targeted therapy.

Patients and Methods

This study included 144 patients diagnosed with PTC who underwent total thyroidectomy and lymph node dissection in the central area of the neck between May 2017 and October 2018. We performed ultra-deep sequencing of 57 genes from 144 patients and detected the 57 genes mutations with bioinformatics.

Results

There were 698 mutations in 45 genes from 138 PTC patients. A high frequency of mutations was detected in the RBM10 gene (44%) and TERT (43%), and some hotspot mutations, such as RBM10:p.E119D and TERT:p.P112fs, were also found.

Conclusion

Ultra-deep sequencing of small gene panels can find some low-frequency mutation genes, which can provide targeted therapy for patients.

New evidence on tumor suppressor activity of PTEN and KLLN in papillary thyroid carcinoma

This study aimed to address the hypothesis that the expression of PTEN and KLLN tumor suppressor genes could diminish in papillary thyroid cancer (PTC) compared to paired normal tissue (PNT) and multinodular goiter (MNG). PTEN and KLLN expressions were assessed at both mRNA and protein levels in 82 tissue samples, including 30 PTC, 30 PNT, and 26 MNG using SYBR-Green Real-Time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. Bioinformatics studies were performed to evaluate the genomic location and the genes promoter region. The mRNA expression of PTEN and KLLN in PTC was significantly lower than PNT (PTEN, P = 0.0033; KLLN, P = 0.0005). A significant decrease in the mRNA level of KLLN was also observed in PTC than MNG (P = 0.0304). Decreased level of PTEN mRNA (odds ratio=0.391; P = 0.013) or KLLN mRNA (odds ratio=0.023; P = 0.025) was associated with an increased risk of PTC tumorigenesis. Areas under the ROC curve for PTEN and KLLN were 0.69 and 0.78, respectively. PTEN and KLLN protein expressions in PTC compared to PNT or MNG were not significantly different. The bioinformatics studies revealed the sequence near the promoter region is lowly conserved across species. Four GC boxes were found upstream of the PTEN transcription start site (TSS), and one TATA box and one GC box were found upstream of KLLN TSS. The results suggest PTEN and KLLN are the two tumor suppressor genes that decreasing or loss of both of them occurs in sporadic PTC tumorigenesis. It appears they could have a promising application in both diagnostic and therapeutic areas.

Thyroid and Molecular Testing. Advances in Thyroid Molecular Cytopathology

Thyroid nodules are a common finding in the adult population including the fact that more than 50% of individuals, over the age of 60, have thyroid nodules. The majority have been mostly detected with ultrasonography and 10% by palpation. The majority of these nodules are benign, whereas 5–15% of them are malignant. The pre-operative diagnosis of cancer is a critical challenge in order to ensure that each patient can be treated with the best tailored management with a reduction of unnecessary surgery for benign lesions. Fine needle aspiration cytology (FNAC) represents the first and most important diagnostic tool for the evaluation of thyroid lesions. According to the literature, FNAC is able to render a conclusive diagnosis in up to 70–80% of all cases. For the remaining 20–30% of nodules, cytological diagnoses fall into the category of indeterminate lesions mostly due to the lack of specific morphological features. According to the Bethesda system for reporting thyroid cytopathology (TBSRTC), indeterminate lesions can be sub-stratified into three different subcategories including “atypia of undetermined significance/follicular lesion of undetermined significance-AUS/FLUS”; “follicular or Hürthle cell neoplasm/suspicious for follicular or Hürthle cell neoplasm-FN/SFN”; and “suspicious for malignancy-SFM”. Many of these indeterminate lesions undergo repetition or diagnostic lobectomy. Nonetheless, the majority of these cases will have a benign diagnosis due to the fact that the rate of cancer ranges between 6 and 30%. It stands to reason that the application of ancillary technique, mostly molecular testing, emerged as a critical additional tool for those thyroid indeterminate lesions. Since the early 1990s, material collected from cytological samples yields sufficient and adequate cells for the detection of point mutation or gene fusions. Nonetheless, the further availability of new sequencing technologies such as next-generation sequencing (NGS) has led to more comprehensive molecular applications adopted now in clinical use. The current review investigates the multiple advances in the field of molecular testing applied in thyroid cytology.

BRAFV600E mutation in the wrong place: a case of concomitant polycythemia vera, hairy cell leukemia, and thyroid adenoma

BACKGROUND

Polycythemia vera (PV) is one of the Philadelphia-negative myeloproliferative neoplasms (MPN), characterized by a pan-myelosis with an erythroid-predominant proliferation mainly driven by somatic JAK2V617F gain-of-function mutation. Hairy cell leukemia (HCL) is a rare B-cell lineage lymphoproliferative disease (LPD) with a typic immunophenotypic profile. BRAFV600E, leading to constitutive activation of the RAF/MEK/ERK signalling pathway and increased cell proliferation, is identified as the driver mutation in almost all cases. Although the risk of developing an LPD is significantly increased in patients with MPN compared with the general population, few cases of co-occurring PV and HCL are reported to date. BRAF is one of the most frequently mutated oncogenes in human cancer and some point mutations were identified in multiple neoplasms in addition to HCL, including follicular and papillary thyroid adenoma and carcinoma.

CASE PRESENTATION

Here we report a molecular diagnostic challenge in a woman with a concomitant diagnosis of JAK2V617F PV, BRAFV600E HCL, and HRASQ61K thyroid follicular adenoma.

CONCLUSION

In the age of molecular and precision medicine, this case underlines the importance of integrating molecular results with clinical, radiologic, cytologic, and histopathologic investigations.

Molecular testing and thyroid nodule management in North America

The incidence of thyroid cancer is rising for a variety of reasons. At the same time, the nomenclature revision of non-invasive encapsulated follicular-variant PTC to noninvasive follicular neoplasm with papillary-like nuclear features (NIFTP) has modified the incidence of thyroid cancer. Given that thyroid neoplasia is a molecular event, it is important for the thyroid physician to evaluate each patient systematically. Most thyroid cancers are sporadic; however, some are familial and may be associated with syndromes with genetic implications. Advances in radiologic imaging have made ultrasonography a near equivalent of gross examination. The American College of Radiology Thyroid Imaging, Reporting and Data System (ACR TI-RADS) classifies nodules from TR1 to TR5 and is valuable in determining which patients should be guided toward fine-needle aspiration (FNA) sampling. While FNA procedures and processing may be varied, the key elements are cytologic diagnosis and collection of samples for potential molecular testing. The Bethesda System for Reporting Thyroid Cytology (BSRTC) is commonly used and categorizes each FNA specimen into one of six diagnoses. The indeterminate diagnoses with risk of malignancy (ROM) ranging from 10-75% comprise approximately 30% of thyroid FNA cases and for these, molecular testing is beneficial. In North America, the two most common molecular platforms are Veracyte Afirma GSC and ThyroSeq v3. Both panels cover an extensive array of genomic alterations associated with thyroid neoplasia and a negative result from either test effectively refines the ROM of an Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance (AUS/FLUS) or Follicular Neoplasm/Suspicious for a Follicular Neoplasm (FN/SFN) diagnosis to 3-4%. Given that the refined ROMs are comparable to that of a Benign BSRTC diagnosis, these patients are recommended for observation of their nodules. However, differences exist in the implication of Afirma GSC-Suspicious and ThyroSeq v3-Positive molecular results with regard to the probability of cancer. For either test, the molecular test result should be integrated with other clinical parameters to determine if surgery is indicated and, if so, the extent of surgery.

Should uncertainty concerning the risk of malignancy be included in diagnostic (nongynecologic) cytopathology reports?

In diagnostic cytology, the known site-specific false positive rates at various anatomical sites for the risk malignancy (ROM) when a confirmed malignant diagnosis is made are comparatively well documented. ROM figures for diagnostic cytology specimens may vary according to the anatomical site of the specimen, the exact nature of the specimen received, the staining method(s) used, and the use of additional laboratory techniques including molecular profiling; furthermore, they often differ to some extent from institution to institution, between differing cytologists within the same institution, and over time. A brief literature review for a selected group of routine diagnostic cytology specimens shows a published ROM for a confirmed malignant diagnosis as follows: bile duct brushings, ~99% (range, 97%-100%); breast fine needle aspiration, 98.5% (range, 92%-100%); serous effusion fluid, 98.9% (range, 90%-100% although lower for squamous cell carcinoma, mesothelioma, and lymphoma), pulmonary endobronchial ultrasound cytology, ~99% (range, 86.6%-100%); thyroid FNA, 98% (range, 97%-99% if NIFTP tumors are excluded), salivary gland FNA, ~90%; (range 57%-100%) and lateral neck cyst FNA, ~99% (range, 95.5%-100%). Because most diagnostic cytology specimens have a small but accepted false-positive rate, this information is vitally important for the clinical management of patients and for shared patient decision making. In our view, the known false-positive rate for a given diagnostic cytology specimen could be included within the cytology report to assist in explaining the limitations of the diagnostic cytology interpretation and help facilitate the clinical decision-making process.

Could Serum TSH Levels Predict Malignancy in Euthyroid Patients Affected by Thyroid Nodules with Indeterminate Cytology?

BACKGROUND

Serum TSH levels in the upper-normal range were reported to be associated with increased risk of thyroid malignancy. However, measurement of TSH levels is currently not recommended for assessing the risk of malignancy in patients with newly diagnosed thyroid nodules.

OBJECTIVE

To evaluate a possible relationship between the serum levels of TSH and the histological outcome of patients undergoing thyroidectomy for thyroid nodules with indeterminate cytology.

MATERIALS AND METHODS

We collected the clinical data of all patients who had performed ultrasound-guided FNA of thyroid nodules with cytological diagnosis of indeterminate lesions (TIR3A and TIR3B) and serum TSH levels within the normal range. All patients had been submitted to thyroid surgery (hemi or thyroidectomy, as appropriate), and histological diagnosis had been performed.

RESULTS

A histological diagnosis of thyroid malignancy was rendered in 74/378 (19.6%) nodules. Patients with histologically proven thyroid malignancy were characterized by higher serum levels of TSH as compared to patients with histologically proven benign nodules (3.03 ± 1.16 vs. 2.37 ± 1.19 mIU/L, p < 0.001). To further analyze the role of serum TSH in predicting thyroid cancer, patients were stratified in 4 groups according to quartiles of TSH concentrations. The prevalence of malignancy was 12.2% for the first quartile and 50.0% for the last quartile. ROC curve analysis identified that a serum TSH level of ≥2.7 mIU/L predicted thyroid malignancy with a sensitivity of 61% and a specificity of 65%.

CONCLUSIONS

TSH levels in the upper-normal range are associated with an increased risk of thyroid malignancy in patients affected by thyroid nodules with indeterminate cytology at FNA. The measurement of serum TSH levels represents an easily performed additional tool for decision-making in patients with indeterminate cytological findings.

Utility of subcategorization of atypia of undetermined significance/follicular lesion of undetermined significance category in ultrasound-guided thyroid fine-needle aspiration in a large referral cancer center

INTRODUCTION

Subclassification of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) is encouraged in the Bethesda System. In our practice, we subclassified AUS/FLUS into 3 subcategories: atypical follicular cells of undetermined significance (ACUS) for cases with cytologic atypia; follicular lesion (FL) for cellular cases with follicular cells with-minimal or no atypia, arranged in a macro- and micro-follicular pattern with scant colloid; and indeterminate follicular lesion, favor benign (IFL-FB) for cases with few clusters of follicular cells without atypia associated with minimal or no colloid. The objective of our study was to evaluate the prevalence, clinical management, and risk of malignancy for each subcategory.

MATERIALS AND METHODS

We retrospectively identified ultrasound-guided fine-needle aspiration (US-FNA) of thyroid cases that were subcategorized as ACUS, IFL-FB, and FL at our-institution during 2014-2016. The results of US-FNA were correlated with clinical outcome in the subsequent 2 years including repeat US-FNA, thyroid surgery, and clinical/imaging follow-up.

RESULTS

Of 3207 thyroid US-FNA cases, 718 (22.4%) cases were included in the study. Of these 718 cases, 104 (14.5%) were subcategorized as ACUS, 166 (23.1%) as FL, and 448 (62.4%) as IFL-FB. The surgery rate was 39.4% (41 of 104) for ACUS, 13.6% (61 of 448) for IFL-FB, and 27.1% (45 of 166) for FL. The risk of malignancy (ROM) was 25% (26 of 104) for ACUS, and 2.9% (13 of 448) for IFL-FB, 6.0% (10 of 166) for FL. The surgery rate and ROM was significantly higher for ACUS in comparison to IFL-FB (P < 0.05) and FL (P < 0.05).

CONCLUSIONS

Subclassification of AUS/FLUS into 3 groups based on cytopathologic findings alone not only improved the triage of patients for subsequent clinical management but also effectively stratified the risk of malignancy.

Ancillary molecular testing of indeterminate thyroid nodules

Cytological specimens from thyroid nodules are increasingly being adopted as the first available material for cost effectively managing patients in the era of personalized medicine. Cytology aspirates not only play a central role in providing accurate diagnoses, but are also being collected for ancillary molecular testing. Molecular analysis, including the evaluation of somatic mutations and other genomic alterations, has accordingly become well integrated in the cytological workup of thyroid lesions. Appropriately handled thyroid cytology preparations provide well-preserved and adequately cellular material with improved DNA/RNA quantity. The recent publication of the 2nd edition of The Bethesda System for Reporting Thyroid Cytopathology and the American Thyroid Association guidelines confirm the relevant role of molecular testing in the management of the different subcategories of indeterminate thyroid lesions. This review discusses the role of molecular testing for indeterminate thyroid nodules, including the recent introduction of the noninvasive, encapsulated follicular variant of papillary thyroid carcinoma (FVPTC), known also as noninvasive follicular neoplasm with papillary-like nuclear features (NIFTP).

The Role of Molecular Testing for the Indeterminate Thyroid FNA

Thyroid nodules are common in the adult population where a majority are benign and only 4.0% to 6.5% are malignant. Fine needle aspiration (FNA) is a key method used in the early stages to evaluate and triage patients with thyroid nodules. While a definitive cytological diagnosis is provided in more than 70–75% of all thyroid FNA cases, the group of indeterminate lesions offers a challenge in terms of interpretation and clinical management. Molecular testing platforms have been developed, are recognized as an option by the 2015 American Thyroid Association Guidelines, and are frequently used in conjunction with FNA as an integral part of the cytologic evaluation. In this review, the utility of molecular testing options for nodules assigned to the group of indeterminate thyroid FNAs is described.

Relevance and clinicopathologic relationship of BRAF V600E, TERT and NRAS mutations for papillary thyroid carcinoma patients in Northwest China

Background

To determine the relevance of the single or combination mutations of BRAF V600E, TERT, and NRAS genes and the clinicopathologic relationship in papillary thyroid cancer (PTC).

Methods

Patients with PTC were enrolled into the study between February 2018 and April 2019. Based on the number of mutant genes, we classified the participants into single BRAF V600E mutation group, double mutations group and no mutation group. Single factor and multiple logistic regression analyses were applied to explore the independent factors. Review Manager 5.3 was used for meta-analysis to review the clinical efficacy of gene co-mutations.

Results

Finally, 483 patients were enrolled into the study and 419 (86.7%) of them harbored BRAF V600E mutation. TERT or NRAS mutation was likely to coexist with BRAF V600E mutation in PTC. BRAF V600E and NRAS promoter co-mutations was identified in 6 patients, with a prevalence of 1.2%. Prevalence of BRAF V600E and TERT coexistence in PTC was 2.1%. Significant differences were found among age, pathology, multifocality, bilateral lesions, lymph node metastasis, and 131I radiotherapy, P < 0.01. Multiple logistic regression analyses demonstrated that age [odds ratio (OR) = 1.044, 95% confidence interval (CI) = 1.013–1.076; P = 0.006], lymph node metastasis [OR = 0.094, 95% CI = 0.034–0.264; P < 0.001], 131I radiotherapy [OR = 7.628, 95% CI = 2.721–21.378; P < 0.001] were risk factors for BRAF V600E mutation. Besides, age [OR = 1.135, 95% CI = 1.069–1.205; P < 0.001], multiple leisions [OR = 4.128, 95% CI = 1.026–16.614; P = 0.046], pathology [OR = 3.954, 95% CI = 1.235–12.654; P = 0.021] were independent factors for combination mutations. Meta-analysis showed significant association of BRAF V600E+/TERT+ co-mutations with lymph node metastasis, multifocality, distant metastasis, tumor recurrence, extrathyroidal extension, and dead of disease.

Conclusions

Prevalence of BRAF V600E mutation in Northwest China was higher than other areas. Age, multiple lesions, and pathology were independent factors for double mutation of BRAF V600E/TERT or BRAF V600E/NRAS. Coexistence of BRAF V600E and TERT promoter mutations was significantly correlated with poor outcome.

The Current Histologic Classification of Thyroid Cancer

Thyroid cancers of follicular cell derivation provide excellent phenotype-genotype correlations. Current morphologic classifications are complex and require simplification. Benign adenomas have follicular or papillary architecture and bland cytology. Well-differentiated thyroid carcinomas exhibit follicular architecture, expansile growth, and variable cytologic atypia and invasiveness; low-risk tumors have excellent prognosis after surgical resection whereas widely-invasive and angioinvasive tumors warrant total thyroidectomy and radioablation. Papillary carcinoma is less differentiated; indolent microcarcinomas can be managed by active surveillance, whereas clinical lesions with local or distant spread require therapy. Progression gives rise to poorly differentiated and anaplastic carcinomas that are less common but far more aggressive.

Immediate Surgery Might Be a Better Option for Subcapsular Thyroid Microcarcinomas

For high-risk papillary thyroid microcarcinomas (PTMCs), immediate surgery is recommended. This study aimed to evaluate the location of PTMCs in the thyroid lobe and determine whether location is associated with an aggressive biology and the necessity of immediate surgery. This retrospective study included 288 patients who underwent initial surgery for PTMC. Clinical data were extracted. Subcapsular thyroid microcarcinomas (STMs) and nonsubcapsular thyroid microcarcinomas (NSTMs), distinguished by ultrasound, were compared in terms of tumour size, extrathyroidal extension, cervical lymph node metastasis, and multifocality. The preoperative ultrasound features predictive of recurrent laryngeal nerve (RLN) involvement were assessed. There were no statistical differences in tumour size (P = 0.985), multifocality (P = 0.866), lymph node metastases to the central compartment (P = 0.154), or lateral lymph node metastases (P = 0.929) between STM and NSTM groups. Macroscopic extrathyroidal extension was exclusively found in the STM group. For assessing RLN involvement, the sensitivity, specificity, and positive predictive value of the presence of an abnormal thyroid capsule margin between the STM and the presumed RLN course, assessed on preoperative ultrasonography images, were 100%, 43.3%, and 43.3%, respectively. Immediate surgery appears to be a better option than conservative treatment for these high-risk STM patients.

Molecular Classification of Thyroid Nodules with Indeterminate Cytology: Development and Validation of a Highly Sensitive and Specific New miRNA-Based Classifier Test Using Fine-Needle Aspiration Smear Slides

Background: Thyroid nodules can be identified in up to 68% of the population. Fine-needle aspiration (FNA) cytopathology classifies 20%-30% of nodules as indeterminate, and these are often referred for surgery due to the risk of malignancy. However, histological postsurgical reports indicate that up to 84% of cases are benign, highlighting a high rate of unnecessary surgeries. We sought to develop and validate a microRNA (miRNA)-based thyroid molecular classifier for precision endocrinology (mir-THYpe) with both high sensitivity and high specificity, to be performed on the FNA cytology smear slide with no additional FNA. Methods: The expression of 96 miRNA candidates from 39 benign/39 malignant thyroid samples, (indeterminate on FNA) was analyzed to develop and train the mir-THYpe algorithm. For validation, an independent set of 58 benign/37 malignant FNA smear slides (also classified as indeterminate) was used. Results: In the training set, with a 10-fold cross-validation using only 11 miRNAs, the mir-THYpe test reached 89.7% sensitivity, 92.3% specificity, 90.0% negative predictive value and 92.1% positive predictive value. In the FNA smear slide validation set, the mir-THYpe test reached 94.6% sensitivity, 81.0% specificity, 95.9% negative predictive value, and 76.1% positive predictive value. Bayes' theorem shows that the mir-THYpe test performs satisfactorily in a wide range of cancer prevalences. Conclusions: The presented data and comparison with other commercially available tests suggest that the mir-THYpe test can be considered for use in clinical practice to support a more informed clinical decision for patients with indeterminate thyroid nodules and potentially reduce the rates of unnecessary thyroid surgeries.

Thyroid FNAC: Causes of false-positive results

In this paper, we aim to focus on false positive results in the evaluation of thyroid aspirations, covering cystic, inflammatory, follicular and oncocytic lesions, papillary carcinoma, and medullary carcinoma of thyroid. The recently described entity noninvasive follicular thyroid neoplasm with papillary-like nuclear features is also discussed detailing the impact of its introduction on the sensitivity and specificity of thyroid FNA, as well as the use of molecular tests for diagnostics. Medicolegal issues in relation to current practice in English law are also described.