Impact of NRAS Mutations on the Diagnosis of Follicular Neoplasm of the Thyroid

Molecular Genetics Augment Cytopathologic Evaluation and Surgical Planning of Pediatric Thyroid Nodules

PURPOSE

Molecular genetic testing in conjunction with cytopathology may improve prediction of malignancy in thyroid nodules, particularly those with indeterminate cytology (Bethesda III/IV). Though now commonplace in adults, pediatric data are limited. This study examines molecular genetics of pediatric nodules with correlation to cytologic and histologic classification at time of surgery and the distribution of mutations.

METHODS

Retrospective chart review of 164 patients <22 years who underwent surgical resection of a thyroid nodule between 2002 and 2020 with molecular testing on fine-needle aspiration biopsy (FNA) or final histopathology.

RESULTS

85 (52 %) of 164 patients undergoing thyroid resection had available molecular genetic testing. BRAF V600E testing was performed on the FNA samples of 73 (86 %) patients and on 15 (18 %) surgical specimens; 31 (37 %) were positive. Of the remaining 54 patients, 21 had additional mutation/fusion testing. In 17 (81 %) cases, an alternate mutation/fusion was identified including 8 gene fusions, 3 DICER1 mutations, 4 NRAS mutations, one BRAF variant, and one unknown variant. BRAF, DICER1 mutations, and gene fusions predicted malignancy. Greater than 95 % of BRAF mutations were in Bethesda V/VI lesions and associated with classic variant PTC whereas fusions and DICER1 mutations clustered in Bethesda IV nodules. Bethesda III nodules harbored BRAF and NRAS mutations. In Bethesda IV nodules, a gene fusion or DICER mutation altered the surgical decision-making (upfront thyroidectomy rather than lobectomy) in 70 % of nodules submitted for genetic testing.

CONCLUSION

Expanded molecular genetic testing on FNA of pediatric thyroid nodules, particularly Bethesda III/IV, may improve prediction of malignancy and augment surgical decision-making.

LEVEL OF EVIDENCE

III.

Bilateral follicular thyroid carcinoma with large sternal metastasis: Case report and review of the literature

INTRODUCTION AND IMPORTANCE

Follicular thyroid cancer (FTC) typically spreads hematogenously, with bone metastasis being worrisome, often appearing to be resistant to radioactive iodine (RAI) therapy. Metastasis to sternum is exceedingly rare.

CASE PRESENTATION

A 43-year-old Egyptian male presented with chest tightness, cough, and shortness of breath. He was initially treated as bronchial asthma. Later, he was referred to our thyroid surgery clinic as a case of goitre and palpable sternal mass. He looked clinically well, with enlarged anterior neck mass and visible sternal mass, no lymphadenopathy. Laboratory tests showed thyroid-stimulating hormone levels within normal (2.13 mIU/L), and mildly decreased FT4 (10.3 pmol/L). Neck/chest CT demonstrated multinodular goitre with retrosternal extension, expansile lytic lesion in the sternum, and bilateral lung metastases. Thyroid fine needle aspiration and cytology showed FLUS, and true cut biopsy from the sternal lesion showed invasive FTC.

DISCUSSION

Rare bilateral FTC presenting as slow-growing sternal metastasis. The patient underwent total thyroidectomy, followed by high dose RAI therapy, and concluded with sternectomy and reconstruction surgery repair using polymethyl methacrylate wrapped in proline mesh. On follow-up, he received further RAI ablation therapy and became RAI refractory. He then received systemic therapy (Lenvatinib). Most recent follow up showed that the disease was controlled (low volume cancer) and he was tolerating treatment well with no reported symptoms.

CONCLUSION

Bilateral FTC with sternal metastasis is rare, and can be treated with total thyroidectomy, sternectomy and reconstruction, followed by RAI therapy and systemic therapy where required, hence inferring real survival benefit.

Real-life utility of five-gene panel test in preoperative thyroid fine-needle aspiration biopsy: a large cohort of 740 patients study

PURPOSE

Fine-needle aspiration (FNA) biopsy is an effective method to discriminate malignant thyroid nodules but reaches indeterminate results in approximately 30% of cases. Molecular testing can improve the diagnostic accuracy of FNA. This study aimed to investigate the real-life utility of the five-gene panel testing in thyroid FNAs.

METHODS

759 thyroid nodules from 740 patients under FNAs were retrospectively enrolled. Gene mutation information and clinical parameters, including age, gender, tumor size, and lymph node metastasis, were respectively recorded. Cytological results were classified based on The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). We analyzed mutational hotspots in BRAF, KRAS, NRAS, HRAS, and TERT genes from FNA specimens. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated to assess diagnostic performance.

RESULTS

We identified 549 five-gene mutations in 759 nodules (72.3%), and the mutation frequency increased from the lower TBSRTC category to the upper category. BRAF.p.V600E showed the highest mutation incidence (71.3%) in the five-gene panel, correlated with the small to medium diameter (p = 0.008, p = 0.012) and high cytological categories (p < 0.001). The sensitivity, specificity, PPV, NPV, and accuracy of the combination of FNA cytology and five-gene detection were 96.83%, 100%, 100%, 42.86%, and 96.90%, respectively.

CONCLUSIONS

The mutation frequency of the five-gene panel is 72.3% in thyroid FNAs. BRAF.p.V600E has the highest alteration rate, which is closely associated with tumor size and cytological results. The five-gene panel can improve the sensitivity and accuracy of FNA cytology, which may represent a valid adjunct technique in distinguishing thyroid nodules.

Genetic determinants of lung cancer: Understanding the oncogenic potential of somatic missense mutations

BACKGROUND

Treatment of lung cancer is getting more personalized nowadays and medical practitioners are moving away from conventional histology-driven empirical treatments, platinum-based chemotherapy, and other invasive surgical resections and have started adopting alternate therapies in which therapeutic targets are patient's molecular oncogenic drivers.

AIM

The aim of the current study is to extract meaningful information from the online somatic mutation data (retrieved from cBioPortal) of 16 most significantly mutated oncogenes in non-small-cell lung cancer (NSCLC), namely EGFR, NRAS, KRAS, HER2 (ERBB2), RET, MET, ROS1, FGFR1, BRAF, AKT1, MEK1 (MAP2K1), PIK3CA, PTEN, DDR2, LKB1 (STK11) and ALK, for improving our understanding of the pathobiology of the lung cancer that can aid decision-making on critical clinical and therapeutic considerations.

METHODS

Using an integrated approach comprising 4 steps, the oncogenic potential of 661 missense non-synonymous single nucleotide polymorphisms (nsSNPs) in 16 genes was ascertained using 2059 NSCLC (1575 lung adenocarcinomas, 484 lung squamous cell carcinomas) patients' online mutation data. The steps used comprise sequence/structure homology-based prediction, scoring of conservation of mutated residues and positions, prediction of resulting molecular and functional consequences using machine-learning and structure-guided approach.

RESULTS

Out of a total of 661 nsSNPs analyzed, a set of 29 nsSNPs has been identified as conserved high confidence mutations in 10 of 16 genes relevant to the under study. Out of 29 conserved high confidence nsSNPs, 4 nsSNPs (EGFR N1094Y, BRAF M620I, DDR2 R307L, ALK P1350T) have been found to be putative novel rare genetic markers for NSCLC.

CONCLUSIONS

The current study, the first of its kind, has provided a list of deleterious non-synonymous somatic mutations in a selected pool of oncogenes that can be considered as a promising target for future drug design and therapy for patients with lung adenocarcinomas and squamous cell carcinomas.

Clinical and pathologic features for predicting malignancy in thyroid follicular neoplasms

Background

The cytologic findings of follicular neoplasm do not distinguish between benign follicular adenoma and follicular thyroid carcinoma (FTC). The objective of this retrospective study was to identify clinical and cytologic/pathologic features to predict malignancy in patients preoperatively diagnosed with follicular neoplasms.

Methods

In total, 416 patients with follicular neoplasms who underwent thyroidectomy were reviewed at Seoul St. Mary's Hospital (Seoul, Korea) from January 2010 to June 2018. Clinicopathological features were analyzed retrospectively by complete medical chart review and pathologic slide review.

Results

Thyroid malignancy/noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was diagnosed in 209 patients (50.2%). In total, 59 patients (14.2%) were diagnosed with FTC, 55 patients (13.3%) were diagnosed with follicular variant papillary thyroid carcinoma (fvPTC). The number of patients with PTC-related nuclear changes was higher in the malignancy/NIFTP group than in the benign group (16.3% vs. 1.9%, P<0.001). Multivariate analysis indicated that the significant risk factors for the diagnosis of malignancy/NIFTP include cytologic or pathologic diagnosis with PTC-related nuclear changes, NRAS mutation, and male sex.

Conclusions

The prevalence of malignancy in patients with a preoperative diagnosis of follicular neoplasm was much higher in our study than in previous reports. Cytologic or pathologic PTC-related nuclear changes is a useful predictor of the presence of malignancy. Further studies must be conducted to support our results.

Clinicopathological parameters for predicting non-invasive follicular thyroid neoplasm with papillary features (NIFTP)

BACKGROUND

Criteria for the preoperative diagnosis of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) have not yet been confirmed. This study aimed to analyze differences in clinicopathological characteristics between follicular variant of papillary thyroid carcinoma (FVPTC) subtypes to determine which parameters are relevant in differentiating NIFTP from other variants.

METHODS

We retrospectively analyzed the records of 199 patients with a preoperative diagnosis of FVPTC who underwent thyroid surgery at Seoul St. Mary's Hospital (Seoul, Korea) from 2011 to 2015. Clinicopathological features were analyzed retrospectively via a complete review of medical charts and pathology reports of patients.

RESULTS

The NIFTP and invasive encapsulated FVPTC (EFVPTC) groups showed relatively benign features, with a majority of the patients categorized as Bethesda category III (25.8% and 25.6%, respectively) or IV (34.8% and 30.2%, respectively), while the infiltrative FVPTC group showed more malignant features, with more patients categorized as category V (28.6%) or VI (47.6%) (p < 0.001). BRAF ^V600E mutations were significantly less prevalent in the NIFTP group (0%) and invasive EFVPTC group (4.7%) compared with the infiltrative FVPTC group (34.9%) (p < 0.001). Multivariate analysis showed that absence of BRAF ^V600E mutation (OR 20.311, p = 0.004) and lymph node metastasis (odds ratio 10.237, p = 0.004) were significantly associated with NIFTP.

CONCLUSION

Although Bethesda category was a statistically significant factor in distinguishing FVPTC subtypes, it was not effective in conclusively distinguishing NIFTP and invasive EFVPTC. Absence of BRAF ^V600E mutation and lymph node metastasis are important features in distinguishing NIFTP from other subtypes.

Clinical Utility of BRAF, NRAS, and TERT Promoter Mutation in Preoperative Thyroid Fine-Needle Aspiration Biopsy: A Diagnostic Study From Dharmais Cancer Hospital

Objective:

Molecular testing of thyroid nodules becomes important for improving the accuracy of fine-needle aspiration biopsy (FNAB). This study aimed to investigate the diagnostic utility of BRAF, NRAS, and TERT promoter mutation in thyroid nodules at Dharmais Cancer Hospital.

Methods:

We performed a prospective diagnostic study involving 50 patients with thyroid nodules who needed surgery between September 2013 and August 2014. Mutational hotspots in BRAF exon 15, NRAS exon 3, and TERT promoter region were analyzed by Sanger sequencing from FNAB specimens. Cytology and molecular data were compared to histopathology results.

Results:

Of the 50 cases included in the analysis, 39 cases (78%) were thyroid malignancies. Mutations of BRAF, NRAS, and TERT promoter were detected in 31% (12/39), 18% (7/39), and 13% (5/39) cases, respectively. BRAF and NRAS mutations were found mutually exclusive, while all of TERT promoter mutation was found coexistent either with BRAF (40%) or NRAS (60%). The combination of FNAB cytology and molecular testing resulted in 69% sensitivity, 100% specificity, 100% positive predictive value, 48% negative predictive value, and 76% accuracy.

Conclusion:

Molecular testing of BRAF, NRAS, and TERT mutations improve the sensitivity of thyroid FNAB and is beneficial for more definitive treatment in selective cases. However, the NPV is relatively low to avoid the need for diagnostic surgery. Therefore, further studies to identify more sensitive methods and more comprehensive molecular markers in the diagnosis of thyroid nodules are needed.

Genetic differences in follicular thyroid carcinoma between Asian and Western countries: a systematic review

Thyroid cancer is the most common endocrine malignancy, and follicular thyroid carcinoma (FTC) is the second most common thyroid cancer following papillary thyroid carcinoma (PTC). RAS mutation and PAX8/PPARγ rearrangement are the two representative genetic alterations in FTC, and there are studies from various countries on their regional frequencies. In this study, we systematically reviewed all available literature aiming to create a complete global map showing the frequencies of these common oncogenic drivers in FTC and to highlight the trends in Asian and Western countries. We performed a search in two electronic databases and identified 71 studies that fit our criteria from 1,329 studies found with our database search terms. There were 54 articles with 1,143 FTC patients and 39 articles with 764 FTC patients available for calculating the frequency of RAS mutation and PAX8/PPARγ rearrangement, respectively. NRAS mutation was the most frequent RAS mutation in all regions, followed by HRAS and KRAS mutation. The frequency of RAS mutation in Asian countries was higher than Western countries (34% vs. 27%, P=0.006) when the mutation detection method was not taken into account. In contrast, this difference in RAS mutation incidence between Asian and Western countries (28% vs. 25%, P=0.47) did not show up in our subgroup analysis incorporating only studies using direct sequencing method. The reported difference of RAS mutation frequency in the previous literature might not be due to the true prevalence of RAS mutation. They could be attributed to the difference in the detection method. As to PAX8/PPARγ rearrangement, Western countries overall had a much higher prevalence than Asian countries (23% vs. 4%, P<0.001), but some European countries had a low incidence, implying regional heterogeneity of PAX8/PPARγ rearrangement. A substantial lack of mutation data in FTC was found in several regions of the world such as Central Asia, Middle East, Africa, and Central and South America. Our results provide the most comprehensive global status of representative genetic alterations in FTC and highlight the similarities and differences between Asian and Western countries.

p21-Activated Kinases in Thyroid Cancer

The family of p21-activated kinases (PAKs) are oncogenic proteins that regulate critical cellular functions. PAKs play central signaling roles in the integrin/CDC42/Rho, ERK/MAPK, PI3K/AKT, NF-κB, and Wnt/β-catenin pathways, functioning both as kinases and scaffolds to regulate cell motility, mitosis and proliferation, cytoskeletal rearrangement, and other cellular activities. PAKs have been implicated in both the development and progression of a wide range of cancers, including breast cancer, pancreatic melanoma, thyroid cancer, and others. Here we will discuss the current knowledge on the structure and biological functions of both group I and group II PAKs, as well as the roles that PAKs play in oncogenesis and progression, with a focus on thyroid cancer and emerging data regarding BRAF/PAK signaling.

2019 Practice guidelines for thyroid core needle biopsy: a report of the Clinical Practice Guidelines Development Committee of the Korean Thyroid Association

Ultrasound-guided core needle biopsy (CNB) has been increasingly used for the pre-operative diagnosis of thyroid nodules. Since the Korean Society of the Thyroid Radiology published the ‘Consensus Statement and Recommendations for Thyroid CNB’ in 2017 and the Korean Endocrine Pathology Thyroid CNB Study Group published ‘Pathology Reporting of Thyroid Core Needle Biopsy’ in 2015, advances have occurred rapidly not only in the management guidelines for thyroid nodules but also in the diagnostic terminology and classification schemes. The Clinical Practice Guidelines Development Committee of the Korean Thyroid Association (KTA) reviewed publications on thyroid CNB from 1995 to September 2019 and updated the recommendations and statements for the diagnosis and management of thyroid nodules using CNB. Recommendations for the resolution of clinical controversies regarding the use of CNB were based on expert opinion. These practical guidelines include recommendations and statements regarding indications for CNB, patient preparation, CNB technique, biopsy-related complications, biopsy specimen preparation and processing, and pathology interpretation and reporting of thyroid CNB.

Rapid On-site Molecular Evaluation in thyroid cytopathology: A same-day cytological and molecular diagnosis

BACKGROUND

Thyroid fine-needle aspirates (FNAs) with undetermined morphology can be outsourced to centralized laboratories for comprehensive molecular profiling. When a local, rapid screening rules out easily detectable BRAF and NRAS mutations outsourcing is minimized, leading to cost savings. The fully automated Idylla technology, that does not require trained staff, is an emerging option. However, Idylla platform has only been validated to process formalin fixed paraffin embedded (FFPE) sections. Here we investigate whether also the FNA needle rinse could be genotyped by the same cytopathologist who performs the FNA, a procedure that can be termed rapid on site molecular evaluation (ROME).

METHODS

To validate this approach, the Idylla BRAF and NRAS Test was performed on the rinses from 25 simulated (bench-top) FNAs, in a first part of the study. Genotyping data were compared with those obtained on matched histological FFPE blocks. The second part of the study was carried out on 25 prospectively collected routine FNAs to assess the performance of the Idylla BRAF and NRAS assay against a gold standard real time polymerase chain reaction method.

RESULTS

Idylla NRAS-BRAF Mutation Test was performed on needle rinse as well as histological FFPE blocks. A sensitivity of 88.9%, a specificity of 100.0% were obtained comparing the Idylla NRAS-BRAF Mutation Test on needle rinse to the reference method.

CONCLUSIONS

The FNA needle rinse can be directly genotyped. This obviates the need of cell block preparation, making possible a rapid combined morphological and molecular evaluation. Since DNA extraction is no longer necessary, the cytopathologist can perform ROME him/herself.

Decision Making in Indeterminate Thyroid Nodules and the Role of Molecular Testing

Cytologically indeterminate thyroid nodules are associated with a broad range (5%-75%) of malignant risk and accurately informing definitive management poses a challenge. Advancements in molecular testing of fine-needle aspiration biopsies have improved preoperative diagnostic accuracy and prognostication. For indeterminate nodules, such testing ideally will reduce the need for surgery for benign nodules and potentially guide appropriate extent of initial surgery for malignancy.

Mutational burdens and evolutionary ages of thyroid follicular adenoma are comparable to those of follicular carcinoma

Follicular thyroid adenoma (FTA) precedes follicular thyroid carcinoma (FTC) by definition with a favorable prognosis compared to FTC. However, the genetic mechanism of FTA to FTC progression remains unknown. For this, it is required to disclose FTA and FTC genomes in mutational and evolutionary perspectives. We performed whole-exome sequencing and copy number profiling of 14 FTAs and 13 FTCs, which exhibited previously-known gene mutations (NRAS, HRAS, BRAF, TSHR and EIF1AX) and copy number alterations (CNAs) (22q loss and 1q gain) in follicular tumors. In addition, we found eleven potential cancer-related genes with mutations (EZH1, SPOP, NF1, TCF12, IGF2BP3, KMT2C, CNOT1, BRIP1, KDM5C, STAG2 and MAP4K3) that have not been reported in thyroid follicular tumors. Of note, FTA genomes showed comparable levels of mutations to FTC in terms of the number, sequence composition and functional consequences (potential driver mutations) of mutations. Analyses of evolutionary ages using somatic mutations as molecular clocks further identified that FTA genomes were as old as FTC genomes. Whole-transcriptome sequencing did not find any gene fusions with potential significance. Our data indicate that FTA genomes may be as old as FTC genomes, thus suggesting that follicular thyroid tumor genomes during the transition from FTA to FTC may stand stable at genomic levels in contrast to the discernable changes at pathologic and clinical levels. Also, the data suggest a possibility that the mutational profiles obtained from early biopsies may be useful for the molecular diagnosis and therapeutics of follicular tumor patients.

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.

Values of molecular markers in the differential diagnosis of thyroid abnormalities

INTRODUCTION

Thyroid cancer (TC), follicular adenoma (FA) and Hashimoto's thyroiditis (HT) are three of the most frequently reported abnormalities that affect the thyroid gland. A frequent co-occurrence along with similar histopathological features is observed between TC and FA as well as between TC and HT. The conventional diagnostic methods such as histochemical analysis present complications in differential diagnosis when these abnormalities occur simultaneously. Hence, the authors recognize novel methods based on screening genetic defects of thyroid abnormalities as viable diagnostic and prognostic methods that could complement the conventional methods.

METHODS

We have extensively reviewed the existing literature on TC, FA and HT and also on three genes, namely braf, nras and ret/ptc, that could be used to differentially diagnose the three abnormalities. Emphasis was also given to the screening methods available to detect the said molecular markers.

RESULTS AND CONCLUSION

It can be conferred from the analysis of the available data that the utilization of braf, nras and ret/ptc as markers for the therapeutic evaluation of FA and HT is debatable. However, molecular screening for braf, nras and ret/ptc mutations proves to be a conclusive method that could be employed to differentially diagnose TC from HT and FA in the instance of a suspected co-occurrence. Thyroid cancer patients can be highly benefited from the screening for the said genetic markers, especially the braf gene due to its diagnostic value as well as due to the availability of personalized medicine targeted specifically for braf mutants.

An Encapsulation of Gene Signatures for Hepatocellular Carcinoma, MicroRNA-132 Predicted Target Genes and the Corresponding Overlaps

OBJECTIVES

Previous studies have demonstrated that microRNA-132 plays a vital part in and is actively associated with several cancers, with its tumor-suppressive role in hepatocellular carcinoma confirmed. The current study employed multiple bioinformatics techniques to establish gene signatures for hepatocellular carcinoma, microRNA-132 predicted target genes and the corresponding overlaps.

METHODS

Various assays were performed to explore the role and cellular functions of miR-132 in HCC and a successive panel of tasks was completed, including NLP analysis, miR-132 target genes prediction, comprehensive analyses (gene ontology analysis, pathway analysis, network analysis and connectivity analysis), and analytical integration. Later, HCC-related and miR-132-related potential targets, pathways, networks and highlighted hub genes were revealed as well as those of the overlapped section.

RESULTS

MiR-132 was effective in both impeding cell growth and boosting apoptosis in HCC cell lines. A total of fifty-nine genes were obtained from the analytical integration, which were considered to be both HCC- and miR-132-related. Moreover, four specific pathways were unveiled in the network analysis of the overlaps, i.e. adherens junction, VEGF signaling pathway, neurotrophin signaling pathway, and MAPK signaling pathway.

CONCLUSIONS

The tumor-suppressive role of miR-132 in HCC has been further confirmed by in vitro experiments. Gene signatures in the study identified the potential molecular mechanisms of HCC, miR-132 and their established associations, which might be effective for diagnosis, individualized treatments and prognosis of HCC patients. However, combined detections of miR-132 with other bio-indicators in clinical practice and further in vitro experiments are needed.

Usefulness of NRAS codon 61 mutation analysis and core needle biopsy for the diagnosis of thyroid nodules previously diagnosed as atypia of undetermined significance

A repeat fine needle aspiration (FNA) is recommended for thyroid nodules diagnosed as atypia of undetermined significance (AUS) in a previous cytology. We evaluated the utility of NRAS codon 61 (NRAS61) mutation analysis and core needle biopsy (CNB) for the diagnosis of thyroid nodules previously diagnosed as AUS. This study enrolled 236 patients who underwent both NRAS61 mutation analysis and CNB of thyroid nodules previously diagnosed as AUS at cytology. The NRAS61 mutation was detected in 36 nodules and was more frequently detected in the AUS and follicular neoplasm (FN)/suspicious for follicular neoplasm (SFN) categories, as determined by histological analysis of CNB, than in the benign group (p = 0.005). Sixty-one patients underwent surgery, and 29 nodules were finally diagnosed as malignant after surgery. Among 61 patients who underwent surgery, nodules with the NRAS61 mutation (42-65 %) had a significantly higher malignancy rate than nodules with wild-type NRAS61 (7-37 %, p = 0.038). The association between malignancy and the NRAS61 mutation was significant after adjusting for age, sex, nodule size, and histological diagnosis of CNB (p = 0.01). NRAS61 mutation analysis together with CNB could be helpful for arriving at a clinical decision in patients with thyroid nodules showing AUS in a previous cytology.

Pathology Reporting of Thyroid Core Needle Biopsy: A Proposal of the Korean Endocrine Pathology Thyroid Core Needle Biopsy Study Group

In recent years throughout Korea, the use of ultrasound-guided core needle biopsy (CNB) has become common for the preoperative diagnosis of thyroid nodules. However, there is no consensus on the pathology reporting system for thyroid CNB. The Korean Endocrine Pathology Thyroid Core Needle Biopsy Study Group held a conference on thyroid CNB pathology and developed guidelines through contributions from the participants. This article discusses the outcome of the discussions that led to a consensus on the pathology reporting of thyroid CNB.