Molecular diagnosis for indeterminate thyroid nodules on fine needle aspiration: advances and limitations

Developing a predictive model for metastatic potential in pancreatic neuroendocrine tumor

CONTEXT

Pancreatic neuroendocrine tumors (PNETs) exhibit a wide range of behavior from localized disease to aggressive metastasis. A comprehensive transcriptomic profile capable of differentiating between these phenotypes remains elusive.

OBJECTIVE

Use machine learning to develop predictive models of PNET metastatic potential dependent upon transcriptomic signature.

METHODS

RNA-sequencing data were analyzed from 95 surgically-resected primary PNETs in an international cohort. Two cohorts were generated with equally balanced metastatic PNET composition. Machine learning was used to create predictive models distinguishing between localized and metastatic tumors. Models were validated on an independent cohort of 29 formalin-fixed, paraffin-embedded samples using NanoString nCounter®, a clinically-available mRNA quantification platform.

RESULTS

Gene expression analysis identified concordant differentially expressed genes between the two cohorts. Gene set enrichment analysis identified additional genes that contributed to enriched biologic pathways in metastatic PNETs. Expression values for these genes were combined with an additional 7 genes known to contribute to PNET oncogenesis and prognosis, including ARX and PDX1. Eight specific genes (AURKA, CDCA8, CPB2, MYT1L, NDC80, PAPPA2, SFMBT1, ZPLD1) were identified as sufficient to classify the metastatic status with high sensitivity (87.5% - 93.8%) and specificity (78.1% - 96.9%). These models remained predictive of the metastatic phenotype using NanoString nCounter® on the independent validation cohort, achieving a median AUROC of 0.886.

CONCLUSIONS

We identified and validated an eight-gene panel predictive of the metastatic phenotype in PNETs, which can be detected using the clinically-available NanoString nCounter® system. This panel should be studied prospectively to determine its utility in guiding operative versus non-operative management.

Positron Emission Tomography/Computed Tomography in Thyroid Cancer: An Updated Review

PET/computed tomography (CT) is a valuable hybrid imaging modality for the evaluation of thyroid cancer, potentially impacting management decisions. 18F-fluorodeoxyglucose (FDG) PET/CT has proven utility for recurrence evaluation in differentiated thyroid cancer (DTC) patients having thyroglobulin elevation with negative iodine scintigraphy. Aggressive histologic subtypes such as anaplastic thyroid cancer shower higher FDG uptake. 18F-FDOPA is the preferred PET tracer for medullary thyroid cancer. Fibroblast activation protein inhibitor and arginylglycylaspartic acid -based radiotracers have emerged as promising PET agents for radioiodine refractory DTC patients with the potential for theranostic application.

A machine-learning algorithm for distinguishing malignant from benign indeterminate thyroid nodules using ultrasound radiomic features

Background: Ultrasound (US)-guided fine needle aspiration (FNA) cytology is the gold standard for the evaluation of thyroid nodules. However, up to 30% of FNA results are indeterminate, requiring further testing. In this study, we present a machine-learning analysis of indeterminate thyroid nodules on ultrasound with the aim to improve cancer diagnosis. Methods: Ultrasound images were collected from two institutions and labeled according to their FNA (F) and surgical pathology (S) diagnoses [malignant (M), benign (B), and indeterminate (I)]. Subgroup breakdown (FS) included: 90 BB, 83 IB, 70 MM, and 59 IM thyroid nodules. Margins of thyroid nodules were manually annotated, and computerized radiomic texture analysis was conducted within tumor contours. Initial investigation was conducted using five-fold cross-validation paradigm with a two-class Bayesian artificial neural networks classifier, including stepwise feature selection. Testing was conducted on an independent set and compared with a commercial molecular testing platform. Performance was evaluated using receiver operating characteristic analysis in the task of distinguishing between malignant and benign nodules. Results: About 1052 ultrasound images from 302 thyroid nodules were used for radiomic feature extraction and analysis. On the training/validation set comprising 263 nodules, five-fold cross-validation yielded area under curves (AUCs) of 0.75 [Standard Error (SE) = 0.04; P < 0.001 ] and 0.67 (SE = 0.05; P = 0.0012 ) for the classification tasks of MM versus BB, and IM versus IB, respectively. On an independent test set of 19 IM/IB cases, the algorithm for distinguishing indeterminate nodules yielded an AUC value of 0.88 (SE = 0.09; P < 0.001 ), which was higher than the AUC of a commercially available molecular testing platform (AUC = 0.81, SE = 0.11; P < 0.005 ). Conclusion: Machine learning of computer-extracted texture features on gray-scale ultrasound images showed promising results classifying indeterminate thyroid nodules according to their surgical pathology.

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.

Trends in Thyroid Fine-Needle Aspiration Cytology Practices: Results From a College of American Pathologists 2016 Practice Survey

CONTEXT.—

The College of American Pathologists periodically surveys laboratories to determine changes in cytopathology practices. We report the results of a 2016 survey concerning thyroid fine-needle aspiration (FNA).

OBJECTIVE.—

To provide a cross-sectional survey of thyroid cytology practices in 2016.

DESIGN.—

In 2016, a survey was sent to 2013 laboratories participating in the College of American Pathologists Non-Gynecologic Cytology Education Program (NGC-A) requesting data from 2015-2016 on several topics relating to thyroid FNA.

RESULTS.—

A total of 878 laboratories (43.6% of 2013) replied to the survey. Radiologists performed the most thyroid FNA procedures in most laboratories (70%; 529 of 756), followed by endocrinologists (18.7%; 141 of 756), and most of these were performed under ultrasound guidance (92.1%; 699 of 759). A total of 32.6% of respondents (251 of 769) provided feedback on unsatisfactory rates for nonpathology providers who performed FNA. Intraprocedural adequacy assessment was primarily performed by attending pathologists (77.4%; 490 of 633) or cytotechnologists (28.4%; 180 of 633). Most laboratories used the Bethesda System for Reporting Thyroid Cytopathology (89.8%; 701 of 781) and performed molecular testing based on clinician request (68.1%; 184 of 270) rather than FNA diagnosis. Correlation of thyroid excisions with prior cytology results most often occurred retrospectively (38.4%; 283 of 737) and was used for pathologist interpretive quality assurance purposes.

CONCLUSIONS.—

These survey results offer a snapshot of national thyroid FNA cytology practices in 2016 and indicate that standardized cytology terminology is commonly used; pathologists perform most immediate adequacy assessments for thyroid FNA; laboratories use correlation statistics to evaluate pathologists' performance; and molecular tests are increasingly requested for indeterminate interpretations, but reflex molecular testing is rare.

Diagnostic Efficacy of Ultrasound-Guided Fine Needle Aspiration Combined with the Bethesda System of Reporting

Background:

Image-guided fine needle aspiration cytology (FNAC) is emerging as an important diagnostic tool in the evaluation of thyroid swellings.

Aim:

This study aims to assess the efficacy of ultrasound (US)-guided FNAC combined with “The Bethesda system' of reporting as a primary screening test for all thyroid lesions.

Settings and Design:

A prospective cohort study was made and all the US-guided FNACs done were followed up to find out the histopathological diagnoses wherever surgery was done.

Materials and Methods:

In all, 1050 patients who underwent US-guided FNAC were studied during a period of 1 year. Age, sex, cytological features, and histological diagnoses were analyzed. Statistical analyses of all the findings were done to derive conclusions.

Results:

Of the 1050 patients, only 10.5% underwent surgery. Higher than expected rate (as per the Bethesda system) of malignancy was noted with the so-called grey zone lesions. The test results revealed a high level of sensitivity, specificity, and diagnostic accuracy.

Conclusion:

The study showed that The Bethesda System of Reporting Thyroid Cytology provides effective communication between clinician and pathologists thereby enabling clear management strategies. We also concluded that US-guided FNACs offer better results compared with palpation-guided FNACs.

Analytical Verification Performance of Afirma Genomic Sequencing Classifier in the Diagnosis of Cytologically Indeterminate Thyroid Nodules

Background: Fine needle aspiration (FNA) cytology, a diagnostic test central to thyroid nodule management, may yield indeterminate results in up to 30% of cases. The Afirma® Genomic Sequencing Classifier (GSC) was developed and clinically validated to utilize genomic material obtained during the FNA to accurately identify benign nodules among those deemed cytologically indeterminate so that diagnostic surgery can be avoided. A key question for diagnostic tests is their robustness under different perturbations that may occur in the lab. Herein, we describe the analytical performance of the Afirma GSC. Results: We examined the analytical sensitivity of the Afirma GSC to varied input RNA amounts and the limit of detection of malignant signals with heterogenous samples mixed with adjacent normal or benign tissues. We also evaluated the analytical specificity from potential interfering substances such as blood and genomic DNA. Further, the inter-laboratory, intra-run, and inter-run reproducibility of the assay were examined. Analytical sensitivity analysis showed that Afirma GSC calls are tolerant to variation in RNA input amount (5-30 ng), and up to 75% dilution of malignant FNA material. Analytical specificity studies demonstrated Afirma GSC remains accurate in presence of up to 75% blood or 30% genomic DNA. The Afirma GSC results are highly reproducible across different operators, runs, reagent lots, and laboratories. Conclusion: The analytical robustness and reproducibility of the Afirma GSC test support its routine clinical use among thyroid nodules with indeterminant FNA cytology.

Cost-effectiveness of Gene Expression Classifier Testing of Indeterminate Thyroid Nodules Utilizing a Real Cohort Comparator

Objective

To predict the cost-effectiveness of implementing routine gene expression classifier testing for thyroid nodules with indeterminate fine-needle aspiration cytology, by utilizing a real cohort of patients as a comparator.

Study Design

Cost-effectiveness analysis of a retrospective cohort compared with a simulated cohort.

Setting

Tertiary academic medical center.

Subjects and Methods

We reviewed the records of all patients who underwent ultrasound-guided fine-needle aspiration from 2010 to 2014 at a tertiary academic medical center. All patients with Bethesda class III or IV cytopathology had the details of their management catalogued over the subsequent 2 years of care. These patients were assigned to the standard-of-care arm of the study. We compared the third-party payer costs of care and the proportion of patients who underwent surgery with a simulated cohort who underwent gene expression classifier testing after an initial indeterminate fine-needle aspiration (molecular test arm).

Results

The cost of managing 1 nodule over 2 years was $2399 higher (range, $397-$4399) for the molecular test group than the standard of care group. The molecular test group had a 13.1% decrease (base parameters; range, 0.73%-45.09%) in the number of patients undergoing surgery.

Conclusion

When applied to a real cohort of patients, routine gene expression classifier is predicted to reduce the number of patients undergoing surgery but will increase cost of care. Cost-effectiveness is heavily dependent on prevalence of malignancy and gene expression classifier specificity.

The role of molecular diagnostic testing in the management of thyroid nodules

INTRODUCTION

Fine needle aspiration (FNA) with cytologic examination remains the standard of care for investigation of thyroid nodules. However, as many as 30% of FNA samples are cytologically indeterminate for malignancy, which confounds clinical management. To reduce the burden of repeat diagnostic testing and unnecessary surgery, there has been extensive investigation into molecular markers that can be detected on FNA specimens to more accurately stratify a patient's risk of malignancy. Areas covered: In this review, the authors discuss recent evidence and progress in molecular markers used in the diagnosis of thyroid cancer highlighting somatic gene alterations, molecular technologies and microRNA analysis. Expert commentary: The goal of molecular markers is to improve diagnostic accuracy and aid clinicians in the preoperative management of thyroid lesions. Modalities such as direct mutation analysis, mRNA gene expression profiling, next-generation sequencing, and miRNA expression profiling have been explored to improve the diagnostic accuracy of thyroid nodule FNA. Although no perfect test has been discovered, molecular diagnostic testing has revolutionized the management of thyroid nodules.

Value of Molecular Tests in Cytologically Indeterminate Lesions of Thyroid

CONTEXT

Fine-needle aspiration has been the initial step in the workup of thyroid nodular lesions and has successfully reduced the number of unnecessary surgeries and improved preoperative malignancy detection. However, up to one-third of cases fall in the diagnostically "indeterminate group," which poses a patient-management challenge. objective: To review the characteristics of molecular tests useful for stratifying the malignancy risk of indeterminate thyroid lesions, including their advantages and limitations.

DATA SOURCES

PubMed.

CONCLUSIONS

Molecular tests are useful for triage of indeterminate thyroid nodules initially diagnosed by using fine-needle aspiration. Immunocytochemistry is readily available with the shortest turnaround time among the molecular tests but suffers from poor reproducibility and low interpretation concordance. Gene mutation analysis is superior in detecting malignancies as a rule-in test, despite low specificity. Next-generation sequencing seems promising but needs more validations before widespread use. Gene expression profiling is more suitable for detecting benign lesions as a rule-out test to avoid unnecessary surgeries but is not reliable in excluding malignancies. MicroRNA profiling has great potential for both risk stratification and predicting prognosis but is limited by significant variations in sensitivity and specificity. Although many questions still need to be answered, taken together, molecular tests are a promising option for classifying cytologically indeterminate thyroid nodular lesions.

Thyroglobulin antibodies as a potential predictive marker of papillary thyroid carcinoma in patients with indeterminate cytology

BACKROUND

We investigated the efficacy of thyroglobulin antibodies (TgAb) in detecting malignancy in indeterminate thyroid nodules and evaluated the possible association between TgAb and autoimmunity in papillary thyroid carcinoma (PTC).

METHODS

This retrospective, nonrandomized study included 1,646 patients who had undergone preoperative fine-needle aspiration biopsy to evaluate their thyroid nodules, and then standard total thyroidectomy. Of 194 patients (11.8%) with indeterminate nodules, 61 (31.4%) had PTC and 133 (68.6%) had benign nodules at the final histologic examination.

RESULTS

Univariate analysis showed that multifocality (P = .002), bilaterality (P = .003), lymph-node metastasis (P = .030), and capsule penetration (P = .003) were significantly associated with positive TgAb in patients with indeterminate cytology and histopathologic diagnosis of PTC. The multivariate analysis showed that TgAb positivity (P < .001) and preoperative thyroid-stimulating hormone levels (P = .022) were independent predictive factor for PTC diagnosis in patients with indeterminate cytology.

CONCLUSIONS

Preoperative TgAb could be a marker for PTC in patients with indeterminate thyroid nodules, increasing diagnostic accuracy. TgAb positivity could also influence the clinical assessment and subsequent selection of total thyroidectomy.

miRNA profiling, detection of BRAF V600E mutation and RET-PTC1 translocation in patients from Novosibirsk oblast (Russia) with different types of thyroid tumors

BACKGROUND

The postoperative typing of thyroid lesions, which is instrumental in adequate patient treatment, is currently based on histologic examination. However, it depends on pathologist's qualification and can be difficult in some cases. Numerous studies have shown that molecular markers such as microRNAs and somatic mutations may be useful to assist in these cases, but no consensus exists on the set of markers that is optimal for that purpose. The aim of the study was to discriminate between different thyroid neoplasms by RT-PCR, using a limited set of microRNAs selected from literature.

METHODS

By RT-PCR we evaluated the relative levels of 15 microRNAs (miR-221, -222, -146b, -181b, -21, -187, -199b, -144, -192, -200a, -200b, -205, -141, -31, -375) and the presence of BRAF(V600E) mutation and RET-PTC1 translocation in surgically resected lesions from 208 patients from Novosibirsk oblast (Russia) with different types of thyroid neoplasms. Expression of each microRNA was normalized to adjacent non-tumor tissue. Three pieces of lesion tissue from each patient (39 goiters, 41 follicular adenomas, 16 follicular thyroid cancers, 108 papillary thyroid cancers, 4 medullary thyroid cancers) were analyzed independently to take into account method variation.

RESULTS

The diagnostic classifier based on profiling of 13 microRNAs was proposed, with total estimated accuracy varying from 82.7 to 99% for different nodule types. Relative expression of six microRNAs (miR-146b, -21, -221, -222, 375, -199b) appeared significantly different in BRAF(V600E)-positive samples (all classified as papillary thyroid carcinomas) compared to BRAF(V600E)-negative papillary carcinoma samples.

CONCLUSIONS

The results confirm practical feasibility of using molecular markers for typing of thyroid neoplasms and clarification of controversial cases.

Five Top Stories in Thyroid Pathology

CONTEXT

Thyroid carcinoma is the most common malignant tumor of endocrine organs, yet it only accounts for approximately 1% of all cancers in the United States with more than 35,000 new cases diagnosed each year and more than 450,000 people living with this disease. While most tumors can be diagnosed without much difficulty, a few tumor types, especially tumors with follicular pattern, sometimes pose a diagnostic challenge.

OBJECTIVE

To discuss morphologic, immunohistochemical, and molecular features of thyroid tumors. We also explore the clinicopathologic features of papillary microcarcinoma and medullary microcarcinoma and how the latter is related and differentiated from C-cell hyperplasia. Finally with the ever-growing list of organ systems involved in immunoglobulin (Ig) G4-related diseases, we discuss the still not completely explored IgG-4-related thyroid disease.

DATA SOURCES

Data were obtained from review of the pertinent peer-reviewed literature and institutional experience.

CONCLUSIONS

Histomorphologic evaluation still remains the gold standard for diagnosis in most cases of thyroid diseases. The application of ancillary studies such as immunohistochemistry and molecular diagnosis, including next-generation sequencing, is becoming more common.

RETRACTED ARTICLE: Thyroid nodules update in diagnosis and management

Thyroid nodules are very common. With widespread use of sensitive imaging in clinical practice, incidental thyroid nodules are being discovered with increasing frequency. Their clinical importance is primarily related to the need to exclude malignancy (4.0 to 6.5 percent of all thyroid nodules), assess for their functional status and any pressure symptoms caused by them. New Molecular tests are marketed for the assessment of thyroid nodules for the presence of cancer. The high prevalence of thyroid nodules requires evidence-based rational strategies for their differential diagnosis, risk stratification, treatment, and follow-up. This review addresses advances and controversies in thyroid nodule evaluation, including the new molecular tests, and their management considering the current guidelines and supporting evidence.

Reclassification of cytologically atypical thyroid nodules based on radiologic features in pediatric patients

AIM

In children the percentage of "Atypia of undetermined significance/follicular lesion of undetermined significance" ("AUS/FLUS") cases is greater and the risk of malignancy is higher than expected. Our study aimed to determine if cytologically atypical nodules can be better characterized using imaging techniques for appropriate management of pediatric patients.

METHODS

Thyroid fine needle aspiration (FNA) specimens were reclassified using the Bethesda System for Reporting Thyroid Cytopathology (BSRTC). Cytologic-histologic correlation was performed to determine if the cytopathologic groups had different associations with the surgical outcome. The "AUS/FLUS" lesions were then subdivided based on radiologic features and the outcome was analyzed for each subgroup.

RESULTS

Histologically benign follicular nodules showed uniform distribution between the "benign" vs. "AUS/FLUS" (p=0.09) or between the "AUS/FLUS" vs. "follicular neoplasm" ("FN") cytologic groups (p=0.27). The follicular neoplasms were also evenly distributed between the "FN" vs. "AUS/FLUS" categories (p=0.31). "Benign", "AUS/FLUS", and "FN" designations showed comparable associations with papillary thyroid carcinoma classical variant (PTC-cv). Reclassification of atypical lesions based on ultrasound findings yielded two subcategories with different risk of malignancy: one similar to the "benign" group (11% malignancy rate) and one comparable with the "FN" category (28% risk of malignant neoplasm).

CONCLUSION

"AUS/FLUS" designation does not add significant value in categorization of pediatric thyroid nodules. These lesions can be reclassified based on radiologic features to provide accurate information for follow-up.

Prediction Table and Nomogram as Tools for Diagnosis of Papillary Thyroid Carcinoma: Combined Analysis of Ultrasonography, Fine-Needle Aspiration Biopsy, and BRAF V600E Mutation

Although ultrasonography (US)-guided fine-needle aspiration biopsy (FNAB) is the most reliable diagnostic modality for evaluating thyroid nodules, 10% to 40% of FNAB samples yield indeterminate findings. The BRAF V600E mutation, a highly specific molecular marker for papillary thyroid carcinoma (PTC), well known for its prognostic value, has dubious diagnostic value because of its low sensitivity. Novel strategies are clearly needed to distinguish PTC, which represents the majority of thyroid malignancies, from other thyroid nodules. The records of 3297 patients with surgically proven PTC were retrospectively reviewed. A prediction table and nomogram were designed using a combination of diagnostic parameters for US, FNAB, and the BRAF V600E mutation. For the nomogram, parameters were proportionally assigned 0 to 100 points according to their regression coefficient for PTC. The probability of PTC for thyroid nodules with intermediate-risk (IR) US and atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) FNAB was significantly dependent on BRAF V600E mutation status based on our prediction table (negative, 29.2% vs positive, 87.5%; P < 0.001). By our nomogram, the probability of PTC for thyroid nodules with IR US, AUS/FLUS FNAB, and positive BRAF V600E mutation was approximately 85% to 90%. We strongly recommend preoperative evaluation of the BRAF V600E mutation in indeterminate thyroid nodules. The prediction table and nomogram developed in this study could help clinicians and patients easily assess the probability of PTC in the preoperative period.

FNA needle rinses preserved in Cytolyt are acceptable specimen type for mutation testing of thyroid nodules

INTRODUCTION

This study investigated the application of molecular testing to residual thyroid fine-needle aspiration material from needle rinses collected in Cytolyt.

MATERIALS AND METHODS

Two thyroid needle rinses from 135 patients were collected in Cytolyt during routine diagnostic workup in our institution. Molecular testing was performed to detect 14 genetic alterations in BRAF, K-, H-, N-RAS genes as well as RET/PTC1, RET/PTC3, and PAX8/PPARγ and verified by next generation sequencing and correlated with cytologic diagnoses.

RESULTS

Molecular testing revealed a total of 17 mutations across specimens with benign nodule (n = 5; HRAS, NRAS), Hürthle cell neoplasm (n = 2; BRAF, HRAS) and Papillary thyroid carcinoma (n = 10, 9 BRAF, 1 KRAS) cytology. No RNA gene rearrangements were detected.

CONCLUSIONS

Mutations and translocations associated with thyroid cancer can be detected in thyroid fine-needle aspiration needle rinses preserved in Cytolyt specimens collected during routine patient management, which are typically discarded when a diagnosis is attained.

Relevance of BRAF(V600E) mutation testing versus RAS point mutations and RET/PTC rearrangements evaluation in the diagnosis of thyroid cancer

BACKGROUND

A molecular profile including BRAF and RAS mutations as well as RET/PTC rearrangement evaluation has been proposed to provide an accurate presurgical assessment of thyroid nodules and to reduce the number of unnecessary diagnostic surgeries, sparing patients' health and saving healthcare resources. However, the application of such molecular analyses may provide different results among different centers and populations in real-life settings. Our aims were to evaluate the diagnostic utility of assessing the presence of BRAF and RAS mutations and RET/PTC1 and RET/PTC3 rearrangements in all cytological categories in an Italian group of thyroid nodule patients assessed prospectively, and to understand whether and which mutation testing might be helpful in cytologically indeterminate nodules.

METHODS

A total of 911 patients were submitted to ultrasound and fine-needle aspiration biopsy examination. Cytological evaluation was performed in parallel with molecular testing and compared to pathological results in 940 thyroid nodules, including 140 indeterminate lesions.

RESULTS

BRAF mutation testing provided the best contribution to cancer diagnosis, allowing the disease to be detected at an early stage, and identifying indeterminate nodules in which diagnostic lobectomy could be spared. On the contrary, RAS and RET/PTC analysis did not further increase diagnostic sensitivity for thyroid cancer. In addition, we found RET/PTC rearrangements in benign lesions, indicating that this molecular marker might not be useful for the detection of thyroid cancer.

CONCLUSION

BRAF(V600E) mutation analysis is superior to RAS point mutations and evaluation of RET/PTC rearrangements in the diagnosis of thyroid cancer, even in indeterminate lesions.

Molecular diagnostic testing of cytology specimens: current applications and future considerations

Molecular mechanisms of pathogenesis continue to be discovered, accelerating significant expansion of the spectrum of clinically useful molecular diagnostic tests and their incorporation into patient care algorithms. Currently, molecular assays facilitate identification of infectious processes, detection of specific constitutional and somatically acquired pathogenic mutations, guidance of therapy selection, and monitoring of treatment response and disease progression. The correlation of genomic test results with clinical, morphologic, and immunophenotypic findings has defined the practice of "precision medicine" with wide-reaching implications for health care. As novel promising techniques such as microarrays and next-generation sequencing are adopted by health care providers, new practice standards are being developed for incorporation into practice. Cytology specimens are good sources of high-quality nucleic acids. Although sometimes limited in quantity, in many cases such specimens are well suited for molecular diagnostic testing, which is capable of maximizing the number of tests from small amounts of sample. The pathologist continues to serve as a central resource for diagnostic testing and consultation regarding appropriate use of molecular tests. Understanding current methodologies, clinical utility of currently available nucleic acid tests, validation requirements for test implementation, quality assurance metrics, and future technology trends is essential to the practice of contemporary molecular pathology.

Imaging, genetic testing, and biomarker assessment of follicular cell-derived thyroid cancer

Thyroid carcinoma is the most common endocrine malignancy worldwide, and its incidence continues to increase. As such the approach to a recently identified thyroid nodule is important to understand. The relevant imaging, examination, and need for fine-needle aspiration biopsy (FNA) are discussed. In approximately 25% of nodules, the diagnosis cannot be established with FNA-based cytology, and surgical excision is necessary for definitive diagnosis. Recent advances in genetic and molecular testing may increase the diagnostic accuracy of FNA in managing thyroid nodules.

Is liquid-based cytology the magic bullet for performing molecular techniques?

OBJECTIVE

The role of pathology has evolved from the first microscopic definitions of diseases by Virchow to the new concept of molecular cytopathology. The management of diseases is now a multidisciplinary approach with the translation of morphological, imagery and molecular findings to therapeutic protocols. Obtaining the most reliable diagnostic material is the essential part of the medical management of patients.

STUDY DESIGN

Here, we try to gain a concise insight into the available data regarding the role of cytology in the application of molecular techniques, focusing on cancer cytopathology.

RESULTS

Obtaining cytological material is now feasible by different methods, and in some cases it is the only possible approach to a lesion which is not easily accessible for tissue sampling. The methods of obtaining cytological material have evolved in recent years in parallel with rapid advances in high-throughput molecular techniques, opening new windows for the diagnosis and management of diseases.

CONCLUSIONS

Different kinds of cytological material are reliable for the application of molecular techniques. Cytological material obtained in a liquid base has advantages such as the better preservation of cytomorphological features and the use of the remaining liquid for nucleic acid extraction even after long storage and the application of molecular methods.