Detection of RET/PTC, TRK and BRAF mutations in preoperative diagnosis of thyroid nodules with indeterminate cytological findings

Testing of mutations on thyroid nodules with indeterminate cytology: A prospective study of 112 patients in Argentina

BACKGROUND

The study of genetic mutations in thyroid nodules makes it possible to improve the preoperative diagnosis of and reduce unnecessary surgeries on benign nodules. In this study, we analysed the impact of implementing a 7-gene mutation panel that enables mutations to be detected in BRAF and RAS (H/N/K) and the gene fusions PAX8/PPARG, RET/PTC1 and RET/PTC2, in a population in northern Argentina.

METHODS

We performed a prospective analysis of 112 fine needle aspirations diagnosed as having indeterminate cytology according to the Bethesda classification system. These include the Bethesda III or atypia of unknown significance/follicular lesion of unknown significance and Bethesda IV or follicular neoplasm/suspicious for follicular neoplasm categories. The mutations of the 7-gene panel were analysed and this information was linked to the available histology and ultrasound monitoring.

RESULTS

The BRAF V600E and RET/PTC1 mutations were associated with carcinoma in 100% of cases (n = 8), whereas only 37.5% (n = 3) of the nodules with RAS and 17% (n = 1) with PAX8/PPARG mutations were associated with carcinoma. From the histological diagnosis and ultrasound monitoring of patients, we can estimate that this panel has a sensitivity of 86% in detecting malignant carcinoma, a specificity of 77%, a positive predictive value (PPV) of 54% and a negative predictive value (NPV) of 94%. In this study, it was possible to reduce the number of surgeries by 48% in the patients analysed.

CONCLUSION

The implementation of the mutation panel allowed the appropriate surgical strategy to be selected for each patient, the number of two-step surgeries to be reduced, and active follow-up to be established in low-risk patients.

Testing of mutations on thyroid nodules with indeterminate cytology: A prospective study of 112 patients in Argentina

BACKGROUND

The study of genetic mutations in thyroid nodules makes it possible to improve the preoperative diagnosis of and reduce unnecessary surgeries on benign nodules. In this study, we analysed the impact of implementing a 7-gene mutation panel that enables mutations to be detected in BRAF and RAS (H/N/K) and the gene fusions PAX8/PPARG, RET/PTC1 and RET/PTC2, in a population in northern Argentina.

METHOD

We performed a prospective analysis of 112 fine needle aspirations diagnosed as having indeterminate cytology according to the Bethesda classification system. These include the Bethesda III or atypia of unknown significance/follicular lesion of unknown significance and Bethesda IV or follicular neoplasm/suspicious for follicular neoplasm categories. The mutations of the 7-gene panel were analysed and this information was linked to the available histology and ultrasound monitoring.

RESULTS

The BRAF V600E and RET/PTC1 mutations were associated with carcinoma in 100% of cases (n=8), whereas only 37.5% (n=3) of the nodules with RAS and 17% (n=1) with PAX8/PPARG mutations were associated with carcinoma. From the histological diagnosis and ultrasound monitoring of patients, we can estimate that this panel has a sensitivity of 86% in detecting malignant carcinoma, a specificity of 77%, a positive predictive value (PPV) of 54% and a negative predictive value (NPV) of 94%. In this study, it was possible to reduce the number of surgeries by 48% in the patients analysed.

CONCLUSION

The implementation of the mutation panel allowed the appropriate surgical strategy to be selected for each patient, the number of two-step surgeries to be reduced, and active follow-up to be established in low-risk patients.

The role of molecular genetics in the presurgical management of thyroid nodules

INTRODUCTION

Fine-needle aspiration (FNA) is an important diagnostic tool for the evaluation of thyroid nodules. However, in almost ¼ of all nodules submitted to FNA cytology is indeterminate. Since the majority of genetic alterations in thyroid cancer have been identified, the use of molecular testing platforms has been endorsed by American Thyroid Association for management of indeterminate nodules.

EVIDENCE ACQUISITION

Several commercial tests were based on mRNA expression of FNA samples (Afirma®, Veracyte, South San Francisco, CA, USA) while others detect DNA alterations (ThyroSeq, UPMC, Pittsburgh, PA, USA). Noncommercial tests detect limited number of point mutations or re-arrangements (gene panels). Literature study included a Pubmed research for adult original studies from 2003 to 2020, focusing on terms such as "molecular tests," "nodules with indeterminate AUS/FLUS and FN/SFN cytology."

EVIDENCE SYNTHESIS

Gene expression profile tests serve as "rule out" tests due to their high negative predictive value and perform better in a setting of low cancer pretest probability. Genetic alteration platforms display high positive predictive value and serve as rather "rule in" tests but their diagnostic accuracy is hampered either because a small proportion of nodules does not harbor any of these alterations targeted (gene panels) or because commonly identified RAS mutations can also be found in benign nodules.

CONCLUSIONS

Next generation sequencing development and incorporation of other genetic markers such as miRNA can improve diagnostic accuracy of molecular tests.

Molecular markers for the classification of cytologically indeterminate thyroid nodules

BACKGROUND

The diagnosis of indeterminate lesions of the thyroid is a challenge in cytopathology practice. Indeed, up to 30% of cases lack the morphological features needed to provide definitive classification. Molecular tests have been developed to assist in the diagnosis of these indeterminate cases. The first studies dealing with the preoperative molecular evaluation of FNA samples focused on the analysis of BRAF^V600E or on the combined evaluation of two or three genetic alterations. The sensitivity of molecular testing was then improved through the introduction of gene panels, which became available for clinical use in the late 2000s. Two different categories of molecular tests have been developed, the 'rule-out' methods, which aim to reduce the avoidable treatment of benign nodules, and the 'rule-in' tests that have the purpose to optimize surgical management. The genetic evaluation of indeterminate thyroid nodules is predicted to improve patient care, particularly if molecular tests are used appropriately and with the awareness of their advantages and weaknesses. The main disadvantage of these tests is the cost, which makes them rarely used in Europe. To overcome this limitation, customized panels have been set up, which are able to detect the most frequent genetic alterations of thyroid cancer.

CONCLUSIONS

In the present review, the most recent available versions of commercial molecular tests and of custom, non-commercial panels are described. Their characteristics and accuracy in the differential diagnosis of indeterminate nodules, namely Bethesda classes III (Atypical follicular lesion of undetermined significance, AUS/FLUS) and IV (Suspicious for follicular neoplasm, FN/SFN) are fully analyzed and discussed.

European perspective on the use of molecular tests in the diagnosis and therapy of thyroid neoplasms

Thyroid nodules are frequently observed, particularly in individuals of over 60 years of age. On the other hand, most of the detected changes are benign and they do not require surgery. Therefore, differentiation between benign and malignant lesions in preoperative diagnosis is of crucial importance. Currently, the use of fine-needle aspiration biopsy (FNAB) and cytological assessment are the gold standard in the diagnosis of thyroid nodules. This procedure significantly reduces the need for diagnostic surgical intervention. However, approximately 15-30% of cytological results are classified as indeterminate. This is mainly due to the lack of specific cytomorphologic features that would facilitate the diagnosis based on cell evaluation under microscopic assessment. For the diagnoses of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), the assessment of invasion is crucial. Such an evaluation is not possible in cytology. Recently, molecular tests have been developed. They improve cytological diagnosis, particularly in the case of indeterminate results. Commercially available tests are developed based on the North American population. It is important to assess whether such tests can be used in the evaluation of e.g., European population.

Human exposure to bisphenol AF and diethylhexylphthalate increases susceptibility to develop differentiated thyroid cancer in patients with thyroid nodules

Pollutants represent potential threats to the human health, being ubiquitous in the environment and exerting toxicity even at low doses. This study aims at investigating the role of fifteen multiclass organic pollutants, assumed as markers of environmental pollution, most of which exerting endocrine-disrupting activity, in thyroid cancer development. The increasing incidence of differentiated thyroid cancer (DTC) may be related to the rising production and environmental dissemination of pollutants. Fifty-five patients, twenty-seven with diagnosis of benign thyroid nodules and twenty-eight suffering from differentiated thyroid cancer, were enrolled and the concentration levels of seven bisphenols, two phthalates (i.e. di(2-ethylhexyl) phthalate (DEHP) and its main metabolite, mono-(2-ethyl-hexyl) phthalate) (MEHP)), two chlorobenzenes, (1,4-dichlorobenzene and 1,2,4,5-tetrachlorobenzene), and 3 phenol derivatives (2-chlorophenol, 4- nonylphenol, and triclosan) were determined in their serum by using a validated analytical method based on high performance liquid chromatography with ultraviolet tandem fluorescence detection. A significant relationship was found between malignancy and the detection in the serum of both bisphenol AF and DEHP. Indeed, their presence confers a more than fourteen times higher risk of developing differentiated thyroid cancer. Relationship between these two pollutants and the risk of malignancy was dose-independent and not mediated by higher thyroid stimulating hormone levels. Even if a conclusive evidence cannot still be drawn and larger prospective studies are needed, the exposure to low doses of environmental endocrine-disrupting contaminants can be considered consistent with the development of thyroid cancer.

The mutational analysis in the diagnostic work-up of thyroid nodules: the real impact in a center with large experience in thyroid cytopathology

PURPOSE

Fine-needle aspiration (FNA) cytology is a mainstay in the evaluation of thyroid nodules, but fails to reach reliable results in 25-30% of cases. The role of molecular markers in helping clinical decisions has been investigated for the last years, but their clinical usefulness is still unsettled.

METHODS

Mutation analysis of BRAF, RAS genes and TERT promoter was performed in a series of 617 consecutive cytological specimens undergoing FNA.

RESULTS

The 617 nodules had the following cytological diagnosis: non diagnostic 22 (3.6%), benign 425 (68.9%), indeterminate 114 (18.5%), suspicious 11 (1.8%) and malignant 45 (7.3%). BRAF mutations were found in 31 cases (5.0%), all but two in suspicious and malignant nodules. RAS mutations were detected in 47 samples (7.6%): 25 benign (5.9%) and 19 indeterminate nodules (16.7%). TERT promoter mutation alone was detected in three samples. Histological outcome was available for 167 nodules, 81 of which proved malignant: all the 48 with suspicious or malignant cytology; 25 out of 56 (44.6%) with indeterminate and 8 out of 57 (14%) with benign cytology. BRAF mutations were associated with worse tumors pathological features. The presence of RAS mutations was indicative of follicular-patterned malignancies in 5 out of 8 benign nodules and 9 out of 11 indeterminate nodules.

CONCLUSIONS

Our study established mutational rates for BRAF and RAS genes in a large series of FNA specimens. BRAF mutations were confirmed as highly specific but not able to improve cytological diagnosis, while RAS testing proved effective in assessing malignancy in nodules with indeterminate and benign cytology.

GDNF and the RET Receptor in Cancer: New Insights and Therapeutic Potential

The Glial cell line-derived neurotrophic Family Ligands (GFL) are soluble neurotrophic factors that are required for development of multiple human tissues, but which are also important contributors to human cancers. GFL signaling occurs through the transmembrane RET receptor tyrosine kinase, a well-characterized oncogene. GFL-independent RET activation, through rearrangement or point mutations occurs in thyroid and lung cancers. However, GFL-mediated activation of wildtype RET is an increasingly recognized mechanism promoting tumor growth and dissemination of a much broader group of cancers. RET and GFL expression have been implicated in metastasis or invasion in diverse human cancers including breast, pancreatic, and prostate tumors, where they are linked to poorer patient prognosis. In addition to directly inducing tumor growth in these diseases, GFL-RET signaling promotes changes in the tumor microenvironment that alter the surrounding stroma and cellular composition to enhance tumor invasion and metastasis. As such, GFL RET signaling is an important target for novel therapeutic approaches to limit tumor growth and spread and improve disease outcomes.

BRAF V600E and RET/PTC Promote the Activity of Nuclear Factor-κB, Inflammatory Mediators, and Lymph Node Metastasis in Papillary Thyroid Carcinoma: A Study of 50 Patients in Inner Mongolia

BACKGROUND The aim of this study was to investigate the expression of the BRAF V600E gene mutation and the RET/PTC gene rearrangement in the progression of papillary thyroid carcinoma (PTC) in 50 patients from Inner Mongolia. MATERIAL AND METHODS Clinical data, blood, and tissue samples were obtained from 50 patients with PTC and ten patients with benign thyroid adenoma. Expression of BRAF V600E, RET/PTC, nuclear factor-κB (NF-κB), interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, C-X-C motif chemokine ligand (CXCL)1, CXCL2, C-C motif chemokine ligand (CCL)2, and CCL3 were measured using polymerase chain reaction (PCR), immunohistochemistry, and an enzyme-linked immunosorbent assay (ELISA). RESULTS Of the 50 patients with PTC, 37 patients expressed the BRAF V600E gene mutation, eight patients expressed RET/PTC, and five patients showed concomitant BRAF V600E and RET/PTC. Time to recurrence for patients with PTC with BRAF V600E was significantly increased compared with patients with concomitant BRAF V600E mutation and RET/PTC rearrangement (P<0.05). Expression of BRAF V600E, RET/PTC, and concomitant expression of BRAF V600E and RET/PTC were significantly associated with patient age and lymph node metastasis (P<0.05). Serum levels of NF-κB, IL-1β, IL-6, TNF-α, TGF-β and CCL3, and tumor tissue levels of IL-1β, IL-6, TNF-α, TGF-β, CXCL2 and CCL2 in patients with PTC were significantly increased compared with patients with benign thyroid adenoma, before and after surgery (P<0.05). CONCLUSIONS Expression of the BRAF V600E mutation and RET/PTC translocation promoted the activity of NF-κB, expression of inflammatory mediators, and lymph node metastases in patients with PTC.

Insights into Current Tropomyosin Receptor Kinase (TRK) Inhibitors: Development and Clinical Application

The use of kinase-directed precision medicine has been heavily pursued since the discovery and development of imatinib. Annually, it is estimated that around ∼20 000 new cases of tropomyosin receptor kinase (TRK) cancers are diagnosed, with the majority of cases exhibiting a TRK genomic rearrangement. In this Perspective, we discuss current development and clinical applications for TRK precision medicine by providing the following: (1) the biological background and significance of the TRK kinase family, (2) a compilation of known TRK inhibitors and analysis of their cocrystal structures, (3) an overview of TRK clinical trials, and (4) future perspectives for drug discovery and development of TRK inhibitors.

Molecular testing in the diagnosis of differentiated thyroid carcinomas

Different genetic mutations and other molecular alterations in papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC) can be detected in fine-needle aspiration (FNA) of thyroid nodules, and can be used successfully to ameliorate cancer diagnosis and management of patients with thyroid nodules. The greatest experience has been obtained with the diagnostic use of BRAF mutation that is strongly specific for malignancy when detected using well-validated techniques. The strongest diagnostic result can be obtained testing FNA samples for a panel of mutations that typically involve TERT, BRAF, PAX8/PPARγ, RAS, and RET/PTC. Finding any of these mutations in a thyroid nodule provides strong indication for malignancy and helps to refine clinical management for a significant proportion of patients with indeterminate cytology. The use of molecular markers, as TERT, BRAF, PAX8/PPARγ, RAS, and RET/PTC, may be considered for patients with indeterminate FNA cytology (FNAC) to help guide management. In patients with indeterminate TIR3 FNA, the combination of precise molecular marker expression analysis with molecular mutations evaluations could ameliorate significantly the accuracy of cancer diagnosis. However other prospective studies are needed to identify more accurate molecular markers. Finally, the knowledge of these molecular pathways has permitted the development of new targeted therapies for aggressive TC.

Diagnostic Utility of Molecular and Imaging Biomarkers in Cytological Indeterminate Thyroid Nodules

Indeterminate thyroid cytology (Bethesda III and IV) corresponds to follicular-patterned benign and malignant lesions, which are particularly difficult to differentiate on cytology alone. As ~25% of these nodules harbor malignancy, diagnostic hemithyroidectomy is still custom. However, advanced preoperative diagnostics are rapidly evolving.This review provides an overview of additional molecular and imaging diagnostics for indeterminate thyroid nodules in a preoperative clinical setting, including considerations regarding cost-effectiveness, availability, and feasibility of combining techniques. Addressed diagnostics include gene mutation analysis, microRNA, immunocytochemistry, ultrasonography, elastosonography, computed tomography, sestamibi scintigraphy, [18F]-2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET), and diffusion-weighted magnetic resonance imaging.The best rule-out tests for malignancy were the Afirma® gene expression classifier and FDG-PET. The most accurate rule-in test was sole BRAF mutation analysis. No diagnostic had both near-perfect sensitivity and specificity, and estimated cost-effectiveness. Molecular techniques are rapidly advancing. However, given the currently available techniques, a multimodality stepwise approach likely offers the most accurate diagnosis, sequentially applying one sensitive rule-out test and one specific rule-in test. Geographical variations in cytology (e.g., Hürthle cell neoplasms) and tumor genetics strongly influence local test performance and clinical utility. Multidisciplinary collaboration and implementation studies can aid the local decision for one or more eligible diagnostics.

Triage of the indeterminate thyroid aspirate: What are the options for the practicing cytopathologist?

Fine-needle aspiration (FNA) plays a key role in the early evaluation of patients with thyroid nodules; however, from 15% to 30% of FNA specimens are cytologically indeterminate. Molecular testing has proven useful when applied to indeterminate thyroid FNAs, and its use has been endorsed in the American Thyroid Association guidelines. In addition to the noncommercial ("in-house") application of v-Raf murine sarcoma viral oncogene homolog B1 (BRAF), rat sarcoma (RAS), rearranged in transformation/papillary thyroid carcinoma (RET/PTC), and peroxisome proliferator-activated receptor γ/paired box gene 8 (PPARγ/PAX8) testing, there are currently 3 commercially available molecular panels that vary in their relative reported performances, strengths, and limitations. Here, we discuss the role of molecular testing for indeterminate thyroid aspirates, taking into consideration the recent reclassification of the encapsulated follicular variant of papillary thyroid carcinoma (PTC) as "noninvasive follicular neoplasm with papillary-like nuclear features (NIFTP)." Cancer Cytopathol 2017;125(6 suppl):477-85. © 2017 American Cancer Society.

Clinical impact of molecular techniques for the presurgical diagnosis of differentiated thyroid cancer diagnosis

The gold standard for the presurgical diagnosis of thyroid cancer is fine needle aspiration cytology. In about 30% of cases a final diagnosis is not obtained and surgical treatment is required for diagnostic/therapeutic purposes. To avoid unnecessary thyroidectomies, methods based on molecular markers analysis have been explored over the last 10 years. Areas covered: The present review introduces the limits of the cytological diagnosis of thyroid nodules and describes the molecular techniques for the presurgical diagnosis of these nodules focusing on the use of the Thyroseq-V2 (Rule in) and Afirma (Rule out) tests. Expert commentary: These two types of tests have been clinically applied and validated; however they are still confined to specialized laboratories, either academic or private, and not yet routinely used. The evidence of a positive cost-benefit analysis should encourage to set up molecular pathology laboratories to apply new molecular testing(s). In the meantime, clinical judgment, which must take into consideration several parameters including the age of the patient, the size and number of the nodule(s), the ultrasound pattern and the risk level for malignancy, should guide the decision to operate or to follow up the evolution of the nodule.

RAS Mutations, and RET/PTC and PAX8/PPAR-gamma Chromosomal Rearrangements Are Also Prevalent in Benign Thyroid Lesions: Implications Thereof and A Systematic Review

BACKGROUND

Molecular markers associated with thyroid malignancy are increasingly being used as differential diagnostic tools for thyroid nodules. However, little has been reported recently regarding the prevalence of these markers in benign lesions. The literature was systematically reviewed to examine studies that reported on the prevalence of these markers in benign thyroid lesions.

METHODS

Appropriate studies published between January 1, 2000, and April 30, 2015, and cataloged in PubMed, Embase, Cochrane, Scopus, and Web of Science databases were searched for by combining different keywords for "thyroid tumor" with both general and specific keywords for "molecular marker" by using "AND" as the Boolean operator. All studies meeting criteria that reported the prevalence of RAS mutations, and RET/PTC and PAX8/PPAR-gamma chromosomal rearrangements in benign thyroid lesions were included for study.

RESULTS

A total of 64 articles (including 8162 patients, of whom 42.5% had benign lesions) that met all the study criteria were systematically reviewed and abstracted. Among 35 studies examining RAS mutations, the reported prevalence of RAS mutation in benign lesions ranged from 0% to 48%. In 38 studies examining RET/PTC rearrangements, the prevalence in benign lesions ranged from 0% to 68%. PAX8/PPAR-gamma rearrangements were examined in 27 studies, with the prevalence in benign lesions ranging from 0% to 55%.

CONCLUSION

The presence of these biomarkers and the tremendous variation in reports of their prevalence in benign lesions suggests the need for caution when including these markers in diagnostic decisions. Further understanding of the importance of these markers, as well as newly discovered markers of thyroid malignancy, may be required in order to avoid overtreatment of patients with benign thyroid tumors.

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.

Application of molecular biology of differentiated thyroid cancer for clinical prognostication

Although cancer outcome results from the interplay between genetics and environment, researchers are making a great effort for applying molecular biology in the prognostication of differentiated thyroid cancer (DTC). Nevertheless, role of molecular characterisation in the prognostic setting of DTC is still nebulous. Among the most common and well-characterised genetic alterations related to DTC, including mutations of BRAF and RAS and RET rearrangements, BRAF^V600E is the only mutation showing unequivocal association with clinical outcome. Unfortunately, its accuracy is strongly limited by low specificity. Recently, the introduction of next-generation sequencing techniques led to the identification of TERT promoter and TP53 mutations in DTC. These genetic abnormalities may identify a small subgroup of tumours with highly aggressive behaviour, thus improving specificity of molecular prognostication. Although knowledge of prognostic significance of TP53 mutations is still anecdotal, mutations of the TERT promoter have showed clear association with clinical outcome. Nevertheless, this genetic marker needs to be analysed according to a multigenetic model, as its prognostic effect becomes negligible when present in isolation. Given that any genetic alteration has demonstrated, taken alone, enough specificity, the co-occurrence of driving mutations is emerging as an independent genetic signature of aggressiveness, with possible future application in clinical practice. DTC prognostication may be empowered in the near future by non-tissue molecular prognosticators, including circulating BRAF^V600E and miRNAs. Although promising, use of these markers needs to be refined by the technical sight, and the actual prognostic value is still yet to be validated.

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

Background:

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

Design:

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

Results:

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

Conclusion:

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

The Diagnostic Performance of Thyroid US in Each Category of the Bethesda System for Reporting Thyroid Cytopathology

We aimed to evaluate the diagnostic performance of thyroid ultrasonography (US) in each category of the Bethesda system and analyze false positive/negative findings using US. This retrospective study included 622 thyroid nodules in 592 patients. The sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and accuracy of US in each category of the Bethesda system were evaluated. False positive/negative cases of US were analyzed. Out of the 622 total thyroid FNAs, 179 (28.8%) were malignant. The malignancy rates for the 6 categories were as follows: I (nondiagnostic): 9.7%, II (benign): 2.5%, III (atypia/follicular lesion of undetermined significance): 37.5%, IV (suspicious for follicular neoplasm): 5.7%, V (suspicious for malignancy): 100%, and VI (malignancy): 100%. The accuracies of US for the 6 categories were 92.5%, 95.6%, 70.8%, 94.3%, 95%, and 92.4% in category order. US showed the lowest sensitivity (50%) in Category IV. Category III demonstrated relatively low sensitivity (66.7%) and specificity (73.3%) due to a high incidence of follicular variant of papillary thyroid carcinoma and a low number of category III nodules. The most optimal performance of US was revealed in Category I with 88.9% sensitivity and 92.9% specificity. In 22 US false positive cases, the most frequent finding was associated with marked hypoechogenicity and the least finding was noncircumscribed margin. The most common US features of 19 false negative cases were circumscribed iso or hypoechoic nodules. These results highlight the excellent diagnostic performance of US in category I of the Bethesda system and the lowest sensitivity of US in category IV. Awareness of US interpreters regarding these pitfalls can minimize false positive/negative diagnoses and prevent unnecessary interventions.

Diagnostic value of BRAF (V600E)-mutation analysis in fine-needle aspiration of thyroid nodules: a meta-analysis

Fine-needle aspiration (FNA) is a reliable method for preoperative diagnosis of thyroid nodules; however, about 10%–40% nodules are classified as indeterminate. The BRAF^V600E mutation is the most promising marker for thyroid FNA. This meta-analysis was conducted to investigate the diagnostic value of BRAF^V600E analysis in thyroid FNA, especially the indeterminate cases. Systematic searches were performed in PubMed, Web of Science, Scopus, Ovid, Elsevier, and the Cochrane Library databases for relevant studies prior to June 2015, and a total of 88 studies were ultimately included in this meta-analysis. Compared with FNA cytology, the synergism of BRAF^V600E testing increased the diagnostic sensitivity from 81.4% to 87.4% and decreased the false-negative rate from 8% to 5.2%. In the indeterminate group, the mutation rate of BRAF^V600E was 23% and varied in different subcategories (43.2% in suspicious for malignant cells [SMC], 13.77% in atypia of undetermined significance/follicular lesion of undetermined significance [AUS/FLUS], and 4.43% in follicular neoplasm/suspicious for follicular neoplasm [FN/SFN]). The sensitivity of BRAF^V600E analysis was higher in SMC than that in AUS/FLUS and FN/SFN cases (59.4% vs 40.1% vs 19.5% respectively), while specificity was opposite (86.1% vs 99.5% vs 99.7% respectively). The areas under the summary receiver-operating characteristic curve also confirmed the diagnostic value of BRAF^V600E testing in SMC and AUS/FLUS rather than FN/SFN cases. Therefore, BRAF^V600E analysis can improve the diagnostic accuracy of thyroid FNA, especially indeterminate cases classified as SMC, and select malignancy to guide the extent of surgery.

MAPK and SHH pathways modulate type 3 deiodinase expression in papillary thyroid carcinoma

Type 3 deiodinase (DIO3, D3) is reactivated in human neoplasias. Increased D3 levels in papillary thyroid carcinoma (PTC) have been associated with tumor size and metastatic disease. The objective of this study is to investigate the signaling pathways involved in DIO3 upregulation in PTC. Experiments were performed in human PTC cell lines (K1 and TPC-1 cells) or tumor samples. DIO3 mRNA and activity were evaluated by real-time PCR and ion-exchange column chromatography respectively. Western blot analysis was used to determine the levels of D3 protein. DIO3 gene silencing was performed via siRNA transfection. DIO3 mRNA levels and activity were readily detected in K1 (BRAF(V6) (0) (0E)) and, at lower levels, in TPC-1 (RET/PTC1) cells (P<0.007 and P=0.02 respectively). Similarly, DIO3 mRNA levels were higher in PTC samples harboring the BRAF(V600E) mutation as compared with those with RET/PTC1 rearrangement or negative for these mutations (P<0.001). Specific inhibition of BRAF oncogene (PLX4032, 3 μM), MEK (U0126, 10-20 μM) or p38 (SB203580, 10-20 μM) signaling was associated with decreases in DIO3 expression in K1 and TPC-1 cells. Additionally, the blockage of the sonic hedgehog (SHH) pathway by cyclopamine (10  μM) resulted in markedly decreases in DIO3 mRNA levels. Interestingly, siRNA-mediated DIO3 silencing induced decreases on cyclin D1 expression and partial G1 phase cell cycle arrest, thereby downregulating cell proliferation. In conclusion, sustained activation of the MAPK and SHH pathways modulate the levels of DIO3 expression in PTC. Importantly, DIO3 silencing was associated with decreases in cell proliferation, thus suggesting a D3 role in tumor growth and aggressiveness.

BRAF-mutated carcinomas among thyroid nodules with prior indeterminate FNA report: a systematic review and meta-analysis

BACKGROUND

Several molecular analyses have been investigated for risk stratification of thyroid nodules, with a particular focus on the V600E mutation of the BRAF gene [BRAF(V600E)]. To date, there is no high-level evidence supporting or refuting a role for BRAF analysis in thyroid nodules with prior indeterminate cytology. To obtain more robust evidence, we reviewed and meta-analysed data from published articles.

RESEARCH DESIGN AND METHODS

A comprehensive literature search of the PubMed/MEDLINE, Embase and Scopus databases was conducted using the terms 'BRAF', 'thyroid' and 'indeterminate'. The search was updated until March 2015, and references of the retrieved articles were also screened. Only original articles reporting BRAF mutation testing within nodules with indeterminate FNA were eligible for inclusion.

RESULTS

The literature search revealed 82 articles, of which 8 were eligible for the study. Five studies were prospective and three retrospective. The majority of authors analysed BRAF mutations in FNA samples which were classified by the British or Bethesda system. Of the initial series of studies, a pooled number of 1361 cases were achieved of which 43 were BRAF mutated. Overall, the BRAF mutation rate was 4·6% (95% CI: 1-10·8%), ranging from 0 to 22·9%. When we included only histological series, 978 thyroid nodules were found. Of these, 245 were cancers.

CONCLUSIONS

A very low rate of lesions with indeterminate cytology are BRAF mutated. Thus, the role of this biomarker to detect or exclude cancers in patients with such FNA reports is marginal and should be reconsidered in guidelines.

Digital gene expression profiling of a series of cytologically indeterminate thyroid nodules

BACKGROUND

Fine-needle aspiration cytology (FNAC) has been widely accepted as the most crucial step in the preoperative assessment of thyroid nodules. Testing for the expression of specific genes should improve the accuracy of FNAC diagnosis, especially when it is performed in samples with indeterminate cytology.

METHODS

In total, 69 consecutive FNACs that had both cytologic and histologic diagnoses were collected, and expression levels of 34 genes were determined in RNA extracted from FNAC cells by using a custom digital mRNA counting assay. A supervised k-nearest neighbor (K-nn) learning approach was used to build a 2-class prediction model based on a subset of 27 benign and 26 malignant FNAC samples. Then, the K-nn models were used to classify the 16 indeterminate FNAC samples.

RESULTS

Malignant and benign thyroid nodules had different gene expression profiles. The K-nn approach was able to correctly classify 10 FNAC samples as benign, whereas only 1 sample was grouped in the malignant class. Two malignant FNAC samples were incorrectly classified as benign, and 3 of 16 samples were unclassified.

CONCLUSIONS

Although the current data will require further confirmation in a larger number of cases, the preliminary results indicate that testing for specific gene expression appears to be useful for distinguishing between benign and malignant lesions. The results from this study indicate that, in indeterminate FNAC samples, testing for cancer-specific gene expression signatures, together with mutational analyses, could improve diagnostic accuracy for patients with thyroid nodules.

Diagnostic performance of elastography in cytologically indeterminate thyroid nodules

Cytological examination of material from fine-needle aspiration biopsy is the mainstay of diagnosis of thyroid nodules, thanks to its remarkable accuracy and scarcity of complications. However, follicular lesions (also called indeterminate lesions or Thy3 in the current classification), a heterogeneous group of lesions in which cytology is unable to give a definitive diagnosis to, represent its main limit. Elastography has been proposed as a potential diagnostic tool to define the risk of malignancy in the aforementioned nodules, but at present there is no conclusive data due to the small number of specifically addressed studies and the lack of concordance among them. The objective of our study was to evaluate the role of real-time elastography (RTE) for refining diagnosis of Thy3 nodules, by integrating diagnostic information provided by traditional ultrasound (US). The study included 108 patients with Thy3 nodules awaiting for surgery, which were evaluated by US (considering hypoecogenicity, irregular margins, microcalcifications, halo sign, and intranodular vascularization) and RTE. Nodules were classified at RTE using a four-class color scale. At histologic examination, 75 nodules were benign and 33 malignant. As expected, none of the ultrasound parameters alone was adequate in predicting malignancy or benignity of the nodules; in the presence of at least two US risk factors, we obtained 61 % sensitivity, 83 % specificity, and 77 % accuracy with 6.8 OR (95 % CI 2.4-20.4). RTE scores 3 and 4 showed 76 % sensitivity, 88 % specificity, 74 % PPV, and 89 % NPV with diagnostic accuracy of 84 %; the data are statistically significant (p < 0.0001) with a OR of 21.9 (95 % CI 7.1-76). By combining RTE with US parameters, the presence of at least 2 characters of suspicion had 88 % sensitivity and 94 % NPV with 23.8 OR (95 % CI 7-106.3). The use of combined RTE and US leads to the identification of two patients subpopulations which have a significantly different malignancy risk (6 vs. 63 %); further studies are needed to verify if it is possible to send only the first group to thyroidectomy and the other to follow-up.

Role of BRAF molecular analysis in the management of papillary thyroid carcinoma: analysis of cytological and histological samples

BACKGROUND

Although fine needle aspiration (FNA) is the standard diagnostic test for the characterization of a suspicious thyroid nodule, in some cases cytological evaluation is inconclusive. The aim of this study was to determine the role of BRAF mutation in aiding diagnosis and to verify whether archival cytological samples could be suitable for molecular analysis.

METHODS

Eighty-five patients with suspicious (Thy4) or follicular (Thy3) lesions on cytology were resubmitted to a second FNA for BRAF mutation analysis. Of these, 56 subsequently underwent surgery. The usefulness of archival samples for molecular analysis was also studied in a second cohort of 42 patients with a confirmed diagnosis of papillary thyroid carcinoma for whom both archived paraffin-embedded histological samples and cytological smears were available. A further 15 patients with paired fresh FNA and archived cytological and histological samples were recruited.

RESULTS

BRAF mutation was found in the fresh FNA samples from 10 of 56 patients who had surgery with previous inconclusive cytology (4/45, 9%, Thy3 and 6/11, 55%, Thy4). The BRAF test showed a specificity and positive predictive value of 100% (26/26 and 10/10, respectively), sensitivity of 33% (10/30) and negative predictive value of 57% (26/46). There was absolute concordance between the BRAF results obtained with 42 histological and cytological archived samples. BRAF analysis on 15 archived cytological samples showed absolute concordance with histology, whereas there was one false negative on the matched fresh FNA.

CONCLUSION

BRAF analysis is a highly specific test that can facilitate cytological diagnosis in some cases and can also be performed on archived cytological samples.

Molecular diagnostics of fine needle aspiration for the presurgical screening of thyroid nodules

"The incidence of thyroid cancer, the most common endocrine malignancy, is rising. The two most common types of thyroid cancer are papillary and follicular" thyroid carcinomas. "Fine-needle aspiration (FNA) of thyroid nodules" can permit to detect many genetic mutations and other molecular alterations, including RAS and BRAF point mutations, PAX8/peroxisome proliferator-activated receptor (PPAR)γ and "RET/PTC rearrangements, occurring in thyroid papillary and follicular carcinomas" (more than 70% of cases), which can be used successfully to improve the diagnosis "and the management of patients with thyroid nodules". The most extensive experience has been accumulated with "the diagnostic use of BRAF mutation", which is highly specific for malignancy. "Testing FNA samples for a panel of mutations" that typically includes RAS, BRAF, PAX8/PPARγ and RET/PTC could permit to achieve the biggest diagnostic impact. "The accuracy of cancer diagnosis in thyroid nodules could be improved significantly using these and other emerging molecular markers".

BRAF V600 co-testing in thyroid FNA cytology: short-term experience in a large cancer centre in the UK

AIMS

To ascertain whether BRAF V600 mutational analysis is useful for diagnosis of thyroid cancer in thyroid fine needle aspirate (FNA).

METHODS

Over 8 months thyroid FNAs reported as Thy 3F (neoplasm possible/suggestive of follicular neoplasm), Thy4 (suspicious of malignancy) and Thy 5 (malignant) were tested for BRAF V600 mutation and managed as malignant if mutations were present.

RESULTS

Of 207 FNAs from 176 patients, 5 were Thy 5, 19 Thy 4, 36 Thy 3f, 13 Thy 3a, 84 Thy 2 and 50 Thy 1. 11 Thy 3f, 15 Thy 4 and 3 Thy 5 FNAs were tested for BRAF V600 mutation. 0 Thy 3F cases, 6 Thy 4 and 1 Thy 5 (24% of the total tested) showed evidence of mutation. Four patients with BRAF V600 mutation underwent surgery to remove all thyroid tissue, two patients received a lobectomy and one patient is awaiting thyroidectomy. All patients with BRAF V600 mutation were found to have malignancy on final histology, with a diagnostic sensitivity for malignancy excluding coincidental microcarcinoma of 43% and specificity of 100%.

CONCLUSIONS

BRAF V600 mutational analysis can enable single-stage total thyroidectomy for carcinoma if gene mutation is present in preoperative FNA. BRAF V600 co-testing may reduce the need for completion thyroidectomy with implied cost savings and lower patient morbidity associated with completion thyroidectomy when the cytology is inconclusive but where BRAF V600 mutation is identified in preoperative thyroid FNA.

Risk stratification based on thyroid cytology: can we rely on national data?

PURPOSE

Determine correlation of malignancy rates between fine needle aspiration (FNA) biopsy and surgical specimen in an urban academic environment.

METHODS

Retrospective review at an academic medical center of fine needle aspiration biopsies and surgical specimens in a head and neck otolaryngology practice between 2000 and 2012.

RESULTS

Of the 74 biopsies diagnosed as follicular lesion, 34 (45.9%) were malignant. Of the 45 biopsies diagnosed as follicular neoplasm, 22 (48.9%) were malignant. These results are significantly higher than the average risk of malignancy cited by the American Thyroid Association of 5%-10% and 20%-30% for follicular lesions and neoplasms respectively.

CONCLUSIONS

The rate of malignancy based on a FNA diagnosis of indeterminate cytology (follicular lesion or follicular neoplasm) can vary greatly among different institutions. Thyroid surgeons should be aware of their local pathology practices to better guide therapy and counsel patients.

BRAF(V600E) assessment by pyrosequencing in fine needle aspirates of thyroid nodules with concurrent Hashimoto's thyroiditis is a reliable assay

Detection of BRAF mutation in cytology specimens has been proposed as a diagnostic adjunctive tool in evaluation of thyroid nodules with indeterminate cytology findings. Concurrent papillary thyroid carcinoma and Hashimoto's thyroiditis (HT), a disease characterized by thyroid lymphocytic infiltration, is a frequent occurrence. A large lymphocytic infiltrate might reduce the sensitivity of methods employed to detect BRAF mutation in thyroid cytology specimens. To determine whether testing for BRAF mutational status in fine needle aspirates (FNA) is reliable also in the presence of HT lymphocytic infiltration, we assessed the BRAF status by direct sequencing and pyrosequencing in a series of FNAs with and without concomitant HT lymphocytic infiltration. We also performed the same assessment by pyrosequencing in the corresponding tissue samples. Pyrosequencing demonstrated to be more sensitive than direct sequencing. The percentage of mutant BRAF(V600E) alleles was higher in FNAs than in the corresponding tissues, probably because of the lower stromal contamination in FNA than in the sections. In the presence of lymphocytic infiltration, the percentage of mutant BRAF(V600E) alleles determined by pyrosequencing was higher in FNAs than in the corresponding tissue samples (P < 0.0001), indicating a minor lymphocytic contamination in FNA. The diagnostic value of BRAF(V600E) in inconclusive FNAs was not hampered by thyroid lymphocytic infiltration. These results indicate that BRAF(V600E) assessment by pyrosequencing is a reliable assay useful to refine inconclusive cytology of thyroid nodules also in the presence of concurrent HT.

Improving the prediction of malignancy in cytologically suspicious thyroid nodules

BACKGROUND

Fine needle cytology aspirates (FNA) classified as THY4 are a heterogeneous group suspicious for malignancy [papillary thyroid cancer (PTC)], which is confirmed in 50-80% of cases after surgery.

AIM

To better stratify THY4 FNA specimens for the relative risk of malignancy.

METHODS

We retrospectively analyzed 78 thyroid nodules classified as THY4 because of the presence of atypical cells, hypercellular trabeculae and/or intranuclear inclusions (ICI), in the absence of papillae. Two subgroups were identified: group 1 (38 nodules), showing ICI with (no.=17) or without (no.=21) trabeculae and cellular atypia, and group 2 (40 nodules), showing trabeculae and atypia but without ICI.

RESULTS

PTC was detected at histology in 56/78 of the patients (71.8%). Malignancy occurred in 36/38 (94.7%) of the patients in group 1 and in 20/40 (50.0%) of the patients in group 2. Therefore, the positive predictive value (PPV) for PTC was 97.3% in the ICI+ specimens (group 1), with a sensitivity of 64.3% and specificity of 95.2%. When only ICI was present, without atypia and trabeculae, the PPV and specificity were similar (95.0 and 95.2%, respectively), but the sensitivity was decreased (48.7%). In specimens without ICI (group 2), the PPV was only 50.0%; however, combined with young age (<40 yr) and male gender, it reached a value similar to that of group1.

CONCLUSIONS

In ICI+ specimens compared to ICI-, the risk of PTC is nearly doubled, since PPV increases from 50.0% to 97.3%. This observation suggests that surgery should be considered mandatory in all lesions classified THY4 at FNA, although the relevant difference in terms of cancer risk between ICI- vs ICI+ nodules might be an useful information for both the clinician and the patient.

Contribution of the BRAF oncogene in the pre-operative phase of thyroid carcinoma

Numerous experiments have been conducted over the last few years aiming to identify molecular markers that show the diagnostic accuracy of fine-needle aspiration (FNA), particularly in thyroid lesions that are considered indeterminate. Using certain search arguments and previously defined criteria, 37 studies reporting experiments with the BRAF mutation in pre-operative FNA of the thyroid were selected from the electronic databases PUBMED, MEDLINE, SCOPUS and LILACS, in order to gather evidence with regard to the possible contribution of BRAF in the management of thyroid carcinoma. There were no cases positive for BRAF in follicular carcinomas (FTCs), Hürthle cell carcinomas (HCCs) or medullary thyroid carcinomas (MTCs). Among the 11 cases of anaplastic thyroid carcinomas (ATC), three showed positive results for the BRAF mutation. The number of cases positive for BRAF among the benign lesions was not significant. The average prevalence of BRAF-positive cases in papillary carcinomas (PTC) was 58.6%, while in follicular variants of papillary carcinoma (FVPTC), the average prevalence was 29.6%. For lesions diagnosed as indeterminate or suspicious, the average prevalence of BRAF positivity in PTC was 48.5%. The experiments included in the present study indicated a specificity of almost 100% and a high predominance of the BRAF mutation in PTC, distinguishing the marker in the planning and medical management of papillary carcinoma of the thyroid.

Is follow-up BRAF(V600E) mutation analysis helpful in the differential diagnosis of thyroid nodules with negative results on initial analysis?

Background

We evaluated the usefulness of follow-up BRAF^V600E mutation analysis using ultrasonography-guided fine-needle aspiration (US-FNA) in diagnosis of thyroid nodules showing negative BRAFV600E mutation on prior analysis.

Methodology/Principal Finding

A total of 49 patients (men: 6, women: 43, mean age: 50.4 years) with 49 thyroid nodules were included. Patients had undergone initial and follow-up US-FNA and subsequent BRAF^V600E mutation analysis from US-FNA aspirates. All patients had negative results on initial BRAF^V600E mutation analysis. Clinicopathologic findings, US assessment, and BRAF^V600E mutation results were analyzed according to the final pathology. Of the 49 nodules, 12 (24.5%) were malignant and 37 (75.5%) were benign. Seven (58.3%) of the 12 malignant nodules were positive for BRAF^V600E mutation on follow-up, all showing suspicious US features. Initial US-FNA cytology of the 7 nodules were non-diagnostic (n = 2), benign (n = 2), or atypia (n = 3), while follow-up were benign (n = 1), indeterminate (n = 1), suspicious for malignancy (n = 4), and malignancy (n = 1).

Conclusions/Significance

Follow-up BRAF^V600E mutation analysis may be helpful in the diagnosis of selected thyroid nodules negative for BRAF^V600E mutation on initial analysis, which are assessed as suspicious malignant on US, diagnosed as non-diagnostic, benign or atypia on follow-up US-FNA.

Preoperative BRAF(V600E) mutation screening is unlikely to alter initial surgical treatment of patients with indeterminate thyroid nodules: a prospective case series of 960 patients

BACKGROUND

Preoperative B-type Raf kinase Val600Glu mutation, or BRAF(V600E), analysis has been proposed as a tool to guide initial surgery for indeterminate thyroid nodules. This study sought to determine if cytologic markers of malignancy are associated with the BRAF(V600E) mutation and if preoperative BRAF(V600E) testing would alter the initial management of patients with indeterminate nodules.

METHODS

Patients who underwent surgery for a thyroid nodule between 2003 and 2012 at a tertiary care center were prospectively enrolled. Stored nodule samples were retrospectively genotyped for the BRAF(V600E) mutation. BRAF(V600E) status, demographics, cytologic and histopathologic findings, and choice of initial surgery were examined.

RESULTS

A total of 960 patients were enrolled, of which 310 (32%) had an indeterminate nodule. The BRAF(V600E) mutation was identified in 13 patients (4%), 12 of whom had either cytologic atypia or were Bethesda category V. Three percent of Bethesda category III or IV nodules that were malignant harbored the mutation compared with 42% of Bethesda category V malignancies. Nuclear grooves (P = .030), pseudoinclusions (P < .001), and oval nuclei (P = .022) were all more common among BRAF(V600E) mutants. The sensitivities of using BRAF testing alone, cytologic atypia/Bethesda category V classification, or both, were 15%, 73%, and 76%, respectively. Twelve of the 13 BRAF(V600E) mutants had total thyroidectomies initially due to worrisome cytologic features, and therefore the initial management of only one patient would have been altered if BRAF(V600E) testing had been performed preoperatively.

CONCLUSIONS

Preoperative mutation screening for BRAF(V600E) does not meaningfully improve risk stratification and is unlikely to alter the initial management of patients with indeterminate nodules.

Q-elastography in the presurgical diagnosis of thyroid nodules with indeterminate cytology

Quantitative ultrasound (US) elastography (Q-USE), able to evaluate tissue stiffness has been indicated as a new diagnostic tool to differentiate benign from malignant thyroid lesions. Aim of this prospective study, conducted at the Department of Surgical Sciences, of the “Sapienza” University of Rome, was to evaluate the diagnostic accuracy of Q-USE, compared with US parameters, in thyroid nodules with indeterminate cytology (Thy3).The case study included 140 nodules from 140 consecutive patients. Patient’s thyroid nodules were evaluated by Q-USE, measuring the strain ratio (SR) of stiffness between nodular and surrounding normal thyroid tissue, and conventional US parameters prior fine-needle aspiration cytology. Those with Thy3 diagnosis were included in the study. Forty of the nodules analyzed harbored a malignant lesion. Q-USE demonstrated that malignant nodules have a significant higher stiffness with respect to benign one and an optimun SR cut-off value of 2.05 was individuated following ROC analysis. Univariate analysis showed that hypoechogenicity, irregular margins and SR >2.05 associated with malignancy, with an accuracy of 67.2%, 81,0% and 89.8%, respectively. Data were unaffected by nodule size or thyroiditis. These findings were confirmed in multivariate analysis demonstrating a significant association of the SR and the irregular margins with thyroid nodule’s malignancy. In conclusion, we demonstrated the diagnostic utility of Q-USE in the differential diagnosis of thyroid nodules with indeterminate cytology that, if confirmed, could be of major clinical utility in patients’ presurgical selection.

Incidence of malignancy in thyroid nodules determined to be follicular lesions of undetermined significance on fine-needle aspiration

BACKGROUND

Fine-needle aspiration (FNA) for thyroid nodules is the most important method for determining a diagnosis. The system for reporting results is based on a cytopathologic classification that stratifies the risk of malignancy.

METHODS

We retrospectively studied 197 patients who underwent FNA for diagnostic evaluation of a thyroid nodule and had their results reported as a follicular lesion of undetermined significance (FLUS) using the Bethesda classification system. The objective of the study was to analyze the incidence and histopathologic types of malignancy in these cases.

RESULTS

The final histopathologic breakdown is as follows: 65 cases (32.9%) of follicular adenoma, 81 cases (41.1%) of microfollicular adenomatoid nodule, 19 cases (9.6%) of microfollicular adenomatoid nodule on the background of thyroiditis, 17 cases (8.6%) of follicular carcinoma, 9 cases (4.6%) of follicular variant papillary carcinoma, and 6 cases (3.1%) of classic papillary carcinoma, for a 16.2% incidence of malignancy. Beyond these diagnoses in the FNA-biopsied nodules, we observed 29 cases (14.7%) of incidental ipsilateral papillary thyroid microcarcinoma (PTM) and 13 cases (6.6%) of incidental contralateral thyroid lobe PTM.

CONCLUSIONS

This study observed a 16.2% incidence of thyroid cancer in the nodule designated FLUS compared to the 5 to 15% rate reported by the Bethesda FNA classification. The overall incidence of incidental PTM in the thyroid gland was 21.3%. These data support considering surgical intervention for at least diagnostic purposes in a patient with the FNAB diagnosis of FLUS.

MicroRNA expression profile helps to distinguish benign nodules from papillary thyroid carcinomas starting from cells of fine-needle aspiration

OBJECTIVE

MicroRNAs (miRNAs) are small endogenous noncoding RNAs that pair with target messengers regulating gene expression. Changes in miRNA levels occur in thyroid cancer. Fine-needle aspiration (FNA) with cytological evaluation is the most reliable tool for malignancy prediction in thyroid nodules, but cytological diagnosis remains undetermined for 20% of nodules.

DESIGN

In this study, we evaluated the expression of seven miRNAs in benign nodules, papillary thyroid carcinomas (PTCs), and undetermined nodules at FNA.

METHODS

The prospective study included 141 samples obtained by FNA of thyroid nodules from 138 patients. miRNA expression was evaluated by quantitative RT-PCR and statistical analysis of data was performed. Genetic analysis of codon 600 of BRAF gene was also performed.

RESULTS

Using data mining techniques, we obtained a criterion to classify a nodule as benign or malignant on the basis of miRNA expression. The decision model based on the expression of miR-146b, miR-155, and miR-221 was valid for 86/88 nodules with determined cytology (97.73%), and adopting cross-validation techniques we obtained a reliability of 78.41%. The prediction was valid for 31/53 undetermined nodules with 16 false-positive and six false-negative predictions. The mutated form V600E of BRAF gene was demonstrated in 19/43 PTCs and in 1/53 undetermined nodules.

CONCLUSIONS

The expression profiles of three miRNAs allowed us to distinguish benign from PTC starting from FNA. When the assay was applied to discriminate thyroid nodules with undetermined cytology, a low sensitivity and specificity despite the low number of false-negative predictions was obtained, limiting the practical interest of the method.

Employing genetic markers to improve diagnosis of thyroid tumor fine needle biopsy

Fine-Needle Aspiration (FNA) is the most widely used and cost-effective preoperative test for the initial evaluation of a thyroid nodule, although it has limited diagnostic accuracy for several types of tumors. Patients will often receive cytological report of indeterminate cytology and are referred to surgery for a more accurate diagnosis. An improved test would help physicians rapidly focus treatment on true malignancies and avoid some unnecessary treatment of benign tumors. This review will discuss current molecular markers that may improve thyroid nodule diagnosis.