The National Cancer Institute Thyroid fine needle aspiration state of the science conference: a summation

Thyroid nodules with benign findings at cytologic examination: results of long-term follow-up with US

PURPOSE

To investigate the natural history of thyroid nodules found to be benign at initial fine-needle aspiration biopsy (FNAB) to determine the percentage of nodules that increased in volume by more than 50% as being an indicator of malignancy.

MATERIALS AND METHODS

This retrospective observational cohort study was approved by the institutional review board, and the need to obtain informed consent was waived. The study included 854 FNAB-confirmed benign thyroid nodules. Suspicious ultrasonographic (US) features included marked hypoechogenicity, irregular or microlobulated margin, microcalcification, and taller-than-wide shape. Univariate and multivariate generalized linear mixed models were used to assess the association with nodule growth greater than 50% in volume.

RESULTS

For the 854 nodules, the initial mean diameter was 19.92 mm (range, 3.10-60.00 mm), and the initial mean volume was 3.19 cm(3) (range, 0.01-4.64 cm(3)). The majority (682 [79.9%] of 854) of thyroid nodules with benign cytologic results at initial FNAB did not grow more than 50% in volume during 4 years of mean follow-up (range, 7-101 months). More than 4 years of follow-up time versus less than 2 years, younger age, a cystic component of less than 25%, and nodule size 1 cm or larger versus less than 1 cm were independently associated with growth. There was only one malignant nodule (0.6%) among 172 thyroid nodules with a volume increase of 50% or greater during the entire follow-up time. Ten malignant nodules (overall malignancy rate: 1.2%) were detected among the 854 total nodules, and eight of these 10 nodules showed suspicious features at US.

CONCLUSION

Repeat FNAB for nodules showing more than 50% growth in volume is unlikely to result in a diagnosis of malignancy. A positive FNAB result for malignancy is significantly more likely in the presence of suspicious US features.

Low nondiagnostic rate for fine-needle capillary sampling biopsy of thyroid nodules: a singular experience

OBJECTIVES

This study examined the hypothesis that sonographically guided fine-needle capillary thyroid biopsies performed by an experienced operator and with constant technique on nodules that meet the Society of Radiologists in Ultrasound criteria warranting biopsy can result in a nondiagnostic rate that is significantly lower than prior published reports.

METHODS

We retrospectively reviewed the sonographic and pathologic reports from 228 consecutive sonographically guided fine-needle capillary thyroid biopsies performed during a 3-year interval by a single operator with more than 15 years of experience performing fine-needle capillary thyroid biopsies. There were no exclusion criteria. Sonographic and pathologic reports from all nodules biopsied were included in the analysis. The radiologist's protocol included 6 fine-needle capillary biopsies, each with 20 passes of the needle into the periphery and/or solid components of the nodule. The cytologic specimens were reviewed off-site in adherence with the Bethesda system for reporting thyroid cytopathologic findings and classified as diagnostic or nondiagnostic. The nondiagnostic rate in this study was compared with the nondiagnostic rates in prior published reports.

RESULTS

Among the 228 fine-needle capillary thyroid biopsies performed during the study interval, cytologic analysis showed 1 nondiagnostic biopsy, yielding a nondiagnostic rate of 0.4%. This rate was significantly lower than previously published reports (P < .001).

CONCLUSIONS

Sonographically guided fine-needle capillary biopsies of the thyroid performed by an experienced radiologist can result in a nondiagnostic rate of less than 1%. This finding warrants further investigation into the reasons for the discrepancy between the results of this study and other previous reports.

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

Indeterminate thyroid lesions are diagnosed in up to 30% of fine needle aspirations. These nodules harbor malignancy in more than 25% of cases, and hemithyroidectomy or total thyroidectomy has therefore been advocated in order to achieve definitive diagnosis. Recently, many molecular markers have been investigated in an attempt to increase diagnostic accuracy of indeterminate fine needle aspiration cytology and thereby avoid unnecessary complications and costs associated with thyroid surgery. Somatic mutation testing, mRNA gene expression platforms, protein immunocytochemistry and miRNA panels have improved the diagnostic accuracy of indeterminate thyroid nodules, and although no test is perfectly accurate, in the authors' opinion, these methods will most certainly become an important part of the diagnostic tools for clinicians and cytopathologists in the future.

Follicular lesion of undetermined significance in thyroid FNA revisited

Controversy exists regarding the validity of follicular lesion of undetermined significance (FLUS), an indeterminate diagnostic category of The Bethesda System for Reporting Thyroid Cytopathology (BSRTC). According to BSRTC, FLUS carries a 5-15% risk of cancer. This study was designed to determine if cytomorphology could stratify FLUS into subgroups with different risks of malignancy. Reports of 127 consecutive FNAs reported as FLUS with subsequent tissue diagnoses were evaluated for the presence of various cytologic features and the results were correlated with histological diagnoses. FLUS cases with focal nuclear atypia (nuclear overlap/crowding, nuclear grooves/membrane irregularities, nuclear enlargement, and/or nuclear pseudoinclusions) were more frequently malignant on excision whereas those with architectural atypia (microfollicles) were more often benign on excision (P < 0.05). The presence of any one or more of these nuclear features increased the risk of carcinoma in subsequent thyroid resection. Papillary carcinomas predominated in excised FLUS cases with focal nuclear atypia whereas most FLUS with architectural atypia were adenomas or hyperplastic nodules on histological evaluation. BSRTC recommends that thyroid aspirates containing follicular cell nuclear and/or architectural atypia insufficient for a diagnosis of suspicious for follicular neoplasm, suspicious for malignancy or malignant be classified as FLUS. Our findings indicate that FLUS cases with focal nuclear atypia carry a risk for malignancy that is substantially higher than that assigned to FLUS and are best classified as suspicious. FLUS cases lacking these atypical nuclear features have a risk for malignancy that approximates the risk BSRTC has assigned to FLUS.

RAS mutations in thyroid cancer

In recent years, our understanding of the genetic alterations underlying thyroid oncogenesis has greatly expanded. The use of molecular markers, including RAS, in the management of thyroid carcinoma is also increasing. This review summarizes the current literature surrounding RAS and discusses its potential as a diagnostic and prognostic indicator in the management of thyroid cancer.

Appropriate and accurate diagnosis of thyroid nodules: a review of thyroid fine-needle aspiration

Thyroid nodules are clinically palpable in 4-7% of adults in the United States. With ultrasound examination, thyroid nodules are identified in up to 70% of adults. In asymptomatic individuals, the potential for malignancy underlies the clinical importance of investigating thyroid nodules. Increased diagnostic accuracy has improved non-operative management of benign thyroid lesions. Appropriate management of thyroid microcarcinoma and large nodules remains a topic of debate. False-negative FNA cytology remains a concern for clinicians treating patients with thyroid nodules. Due to the challenge of interpreting FNA cytology and recent changes to the cytopathologic classification system, we reviewed the current literature on diagnosis of thyroid nodules using the recent Bethesda criteria.

Thin core biopsy should help to discriminate thyroid nodules cytologically classified as indeterminate. A new sampling technique

Indeterminate neoplasms (IN) represent the gray zone of thyroid cytology in which malignant and benign tumors cannot be discriminated. Recently, the approach by thin core needle biopsy has been proposed. Here we report a new thin core needle biopsy approach in 40 consecutive patients with thyroid IN at cytology. In this study, a 21-G needle was inserted into the nodule, advanced within the lesion, and moved ahead reaching extranodular tissue. The resulting sample allowed to evaluate the cytomorphology of nodular tissue, its relationship with extranodular parenchyma, and the nodule's capsule when present. All biopsies were adequate for diagnosis but one. Of the 39 adequate samples, 5 cases were papillary cancer as confirmed at histology, while 14 nodules avoided surgery because of Hürthle cell hyperplasia in thyroiditis (n = 6) and microfollicular adenomatous hyperplasia (n = 8). The remaining 20 cases were assessed as follicular neoplasms because of encapsulation and were evaluated by immunohistochemistry. Of these, 6 had positive markers in different degree and 1/6 has follicular cancer at histology, while the other 14 were benign after surgery. Overall, this approach by thin core needle biopsy identified benignancy in 14/40 (35 %) IN avoiding surgery. As a conclusion, thin core biopsy should help to discern the nature of thyroid lesions cytologically classified as indeterminate, and it should be used as a complementary test in thyroid nodule assessment.

Radiologic and clinical predictors of malignancy in the follicular lesion of undetermined significance of the thyroid

Various ultrasonographic characteristics of thyroid nodules have been associated with a higher likelihood of malignancy, and certain clinical features may also increase the likelihood of malignancy in patients. This study is designed to determine the ultrasonographic and clinical predictors of malignancy in the atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) category. A search through the cytology files at our institution was made for cases with diagnosis of AUS/FLUS. The clinical and radiologic findings were correlated with the final surgical pathology diagnosis. A total of 140 cases of AUS/FLUS with corresponding surgical intervention were identified (112 females and 28 males). There was a 79 % malignancy rate in nodules with irregular contours, compared to 51 % in nodules with regular outlines. Nodules demonstrating calcifications showed a 57 % malignancy rate, compared to 50 % in nodules without calcifications. Sixty-one percent of cases with an ultrasonographic diagnosis of indeterminate to suspicious were malignant following surgical resection. The rates of malignancy in patients with radiation exposure, symptomatic nodules, and positive family history of thyroid cancer were 22, 59, and 33 %, respectively. BRAF mutation was demonstrated in 57 % of malignant cases and in none of benign cases. No single clinical or ultrasonographic feature or combination of features is adequately sensitive or specific to identify all malignant nodules. However, a combination of solid nodules, nodules with irregular contours, symptomatic nodules, and positive BRAF mutation has high predictive value for malignancy in patients with a cytologic diagnosis of AUS/FLUS.

Sonographically suspicious thyroid nodules with initially benign cytologic results: the role of a core needle biopsy

PURPOSE

To evaluate the diagnostic role of core needle biopsy (CNB) in sonographically suspicious thyroid nodules with initially benign cytologic results through a histologic analysis of CNB specimens.

METHODS

Between October 2008 and July 2011, 88 patients underwent ultrasound (US)-guided CNB for initially benign cytologic results with suspicious US features at our institution. In all, 85 patients with 85 focal thyroid nodules were included in the study after surgery or concordant benign readings following fine-needle aspiration biopsy (FNAB) and CNB. We evaluated the risk of malignancy, diagnostic performance of CNB, and histologic findings for these nodules.

RESULTS

Of the 85 nodules, 28 (32.9%) were histologically upgraded on CNB specimens including one case of atypia of undetermined significance (AUS), seven cases of follicular neoplasm, one case of suspicious for malignancy, and 19 cases of malignancy. Of these, 27 (31.8%) were finally confirmed as malignant, and one as follicular adenoma at surgery. The 27 malignant nodules included 21 papillary thyroid carcinomas (PTCs), five follicular thyroid carcinomas, and one Hürthle cell carcinoma. All PTCs were diagnosed from CNB readings of AUS suspicious for malignancy or malignancy. Follicular thyroid carcinomas and Hürthle cell carcinoma were diagnosed from CNB readings of follicular neoplasm. Histologic analysis of benign CNB specimens revealed severe fibrosis (96.4%), hemosiderin (21.4%), calcification (17.9%), granulation tissue (12.5%), and focal lymphocytic thyroiditis (12.5%).

CONCLUSIONS

The histologic information obtained by analysis of CNB specimens may enable more confident diagnosis for benign nodules with suspicious US features and reduce the need for repetitive FNABs or diagnostic surgery.

Ultrasonography-guided core needle biopsy for the thyroid nodule: does the procedure hold any benefit for the diagnosis when fine-needle aspiration cytology analysis shows inconclusive results?

OBJECTIVE

We evaluated the diagnostic role of ultrasonography-guided core needle biopsy (CNB) according to ultrasonography features of thyroid nodules that had inconclusive ultrasonography-guided fine-needle aspiration (FNA) results.

METHODS

A total of 88 thyroid nodules in 88 patients who underwent ultrasonography-guided CNB because of previous inconclusive FNA results were evaluated. The patients were classified into three groups based on ultrasonography findings: Group A, which was suspicious for papillary thyroid carcinoma (PTC); Group B, which was suspicious for follicular (Hurthle cell) neoplasm; and Group C, which was suspicious for lymphoma. The final diagnoses of the thyroid nodules were determined by surgical confirmation or follow-up after ultrasonography-guided CNB.

RESULTS

Of the 88 nodules, the malignant rate was 49.1% in Group A, 12.0% in Group B and 90.0% in Group C. The rates of conclusive ultrasonography-guided CNB results after previous incomplete ultrasonography-guided FNA results were 96.2% in Group A, 64.0% in Group B and 90.0% in Group C (p=0.001). 12 cases with inconclusive ultrasonography-guided CNB results were finally diagnosed as 8 benign lesions, 3 PTCs and 1 lymphoma. The number of previous ultrasonography-guided FNA biopsies was not significantly different between the conclusive and the inconclusive result groups of ultrasonography-guided CNB (p=0.205).

CONCLUSION

Ultrasonography-guided CNB has benefit for the diagnosis of thyroid nodules with inconclusive ultrasonography-guided FNA results. However, it is still not helpful for the differential diagnosis in 36% of nodules that are suspicious for follicular neoplasm seen on ultrasonography.

ADVANCES IN KNOWLEDGE

This study shows the diagnostic contribution of ultrasonography-guided CNB as an alternative to repeat ultrasonography-guided FNA or surgery.

Thyroid nodules with initially nondiagnostic cytologic results: the role of core-needle biopsy

PURPOSE

To evaluate the role of core-needle biopsy (CNB) in thyroid nodules with nondiagnostic results at previous fine-needle aspiration (FNA).

MATERIALS AND METHODS

From October 2008 to July 2011, 155 nodules from 155 patients (37 men, 118 women) with a mean age of 51.8 years (age range, 22-76 years) with nondiagnostic results at previous FNA were reviewed retrospectively. The Bethesda system for reporting thyroid cytopathologic results was used to assign FNA and CNB findings. Malignant nodules (n = 37) were diagnosed after surgery. Benign nodules (n = 79) were diagnosed either after surgery, with benign findings after FNA and/or CNB that had been repeated at least twice, or after benign cytology findings at FNA or CNB with a stable size at follow-up. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ultrasonographically guided CNB were evaluated.

RESULTS

At CNB, two nodules (1.3%) showed nondiagnostic results, and 135 nodules (87.1%) had conclusive diagnoses. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of core biopsies for the detection of malignancy were 94.6% (35 of 37), 100% (79 of 79), 100% (35 of 35), 97.5% (79 of 81), and 98.3% (114 of 116), respectively. For 28 nodules, nondiagnostic results were found after two or more FNA procedures; however, diagnostic surgery was performed in only one patient.

CONCLUSION

CNB of the thyroid nodule demonstrates high rates of conclusive and accurate diagnoses in patients for whom previous FNA results were nondiagnostic, thereby reducing the need for unnecessary diagnostic surgery.

The impact of implementing The Bethesda System for reporting of thyroid FNA at an academic center

Recently, a six-tiered diagnostic risk classification system was created based on the recommendations of the National Cancer Institute (NCI) sponsored NCI Thyroid Needle Aspiration State of the Science Conference at Bethesda, MD in October 2007. The objective of the current study was to compare the frequency distribution of the various diagnostic categories to evaluate its diagnostic performance before and after implementation of The Bethesda System (TBS). A total of 5,897 thyroid Fine needle aspirations (FNAs) were reviewed; 3,207 were from 2008 after TBS implementation, and 2,690 were from 2007 immediately before TBS implementation. Follow-up consisted of reviewing corresponding histologic results. The rates of "Nondiagnostic" specimens and cases with a diagnosis of "Follicular Neoplasm" decreased from 13.1 to 11.1% and 8.6 to 5.5%, respectively, after implementation of TBS, while the rate of negative specimens increased from 68.2 to 73.8%. The other categories remained relatively stable. In addition, there also was a significant decrease in the use of noncommittal descriptive diagnoses. The diagnostic performance of thyroid FNA in identifying a neoplastic process as measured by area under the receiver operating characteristic curve increased from 0.88 to 0.89; the difference was statistically significant (P=0.03). Implementation of TBS showed a significant reduction of: nondiagnostic thyroid FNAs, of FNAs with a diagnosis of "Follicular Neoplasm," as well as cases with descriptive noncommittal diagnoses. TBS results in improved diagnostic performance and therefore more consistent and uniform reporting of thyroid FNA.

Interobserver agreement for thyroid elastography: value of the quality factor

OBJECTIVES

The purpose of our study was to investigate interobserver agreement for thyroid ultrasound elastography and to analyze the reproducibility of real-time freehand elastography in thyroid nodules.

METHODS

A prospective nonrandomized double-blind study was conducted between September 2008 and June 2010. Real-time elastography of 89 thyroid nodules was performed by two radiologists, with the first radiologist evaluating each thyroid nodule 5 minutes before the second. The elastograms were obtained with the patients holding their breath and considered valid when the quality factor was 50 or higher. The region of interest was positioned to include the nodule and 0.5 cm of surrounding normal thyroid parenchyma but to exclude the carotids and esophageal-tracheal structures. The elastograms were classified on a scale of 5 different patterns.

RESULTS

Observers 1 and 2 coincided in 79 elastographic patterns and disagreed on 10 nodules (11.2%). The results between the radiologists had a statistically significant agreement (P < .005), with a κ value of 0.838.

CONCLUSIONS

The introduction of a quality factor in elastographic software and the selection of elastograms with a quality factor of 50 or higher confer almost perfect interobserver agreement for thyroid nodule elastography and make elastography a reproducible technique that could be used in daily clinical practice.

The value of preoperative PET-CT in papillary thyroid cancer

OBJECTIVE

To evaluate the clinical usefulness of preoperative positron emission tomography-computed tomography (PET-CT) in primary papillary thyroid cancer (PTC).

METHODS

Preoperative PET-CT scans of patients with biopsy-confirmed PTC who were undergoing thyroidectomy were examined and the maximum standardized uptake value (SUV max) of 2-deoxy-2-((18)F)fluoro-D-glucose ((18)F-FDG) was calculated. Demographic and clinical data were obtained from medical records. Tumour tissue was pathologically classified according to World Health Organization guidelines. Univariate and multivariate analyses were performed to determined the demographic, clinical and pathological factors affecting PET positivity and SUV max.

RESULTS

The study included 194 patients. Multivariate analysis indicated that patients were significantly more likely to be PET positive if they were female, had larger tumours (>1 cm), coexisting pathology (nodular hyperplasia or Hashimoto's thyroiditis) or nonfollicular variant PTC. SUV max <2.0 indicated possible follicular variant PTC.

CONCLUSIONS

PET-positive results were unrelated to extrathyroidal extension and lymph node metastasis. PET positivity was related to larger tumour size and implied coexisting pathology. PET negativity or low SUV max suggested possible follicular variant PTC.

BRAFV600E mutation in papillary thyroid microcarcinoma: a genotype-phenotype correlation

BRAF(V600E) mutation has emerged as a marker of aggressive behavior in papillary thyroid carcinoma but its significance in microcarcinoma is not entirely clear. One-hundred and twenty-nine papillary thyroid microcarcinomas were tested for BRAF(V600E) mutation by single-strand conformation polymorphism, and their clinicopathologic features (age, sex, tumor size, multifocality, nodal metastases, histologic subtype, tumor cell morphology, architecture, tumor-associated stromal reaction, tumor interface to non-neoplastic thyroid (well circumscribed vs infiltrative), extrathyroidal extension, lymphovascular invasion, intratumoral multinucleated giant cells, and adjacent non-neoplastic thyroid pathology) were examined. Compared with tumors without the mutation (39/129, 30%), the mutated microcarcinomas (90/129, 70%) showed significantly higher prevalence of infiltrative tumor borders (78/90 vs 23/39, P=0.001), tumor-associated stromal desmoplasia/fibrosis and/or sclerosis (80/90 vs 25/39, P=0.002), classic nuclear features of papillary thyroid carcinoma (90/90 vs 35/39, P=0.008) and cystic change (43/90 vs 11/39, P=0.05). BRAF(V600E) mutation was more frequent in classic (75%), tall cell (91%), and other variants (>70%) than in follicular variant (21%) of papillary thyroid microcarcinoma. Tumors without the mutation were significantly more likely to be solid, well circumscribed, and lacked desmoplasia/fibrosis or sclerosis. However, on multivariate analysis, only the follicular variant of papillary microcarcinoma was significantly associated with the absence of mutation (odds ratio (95% confidence interval): 0.09 (0.01-0.54)). Lymph node metastases (n=24) were more frequent in microcarcinomas with mutation than without (21/24 vs 3/24, P=0.02). All patients with lateral cervical node metastasis (n=9), and all but one tumor with extrathyroidal extension (n=17/18) showed BRAF(V600E) mutation. No significant differences were noted in age, sex, tumor size, multifocality, lymphovascular invasion, psammoma bodies, stromal calcification, intratumoral multinucleated osteoclastic-type giant cells, and lymphocytic infiltration between the two groups of tumors. BRAF(V600E) mutation is an early event in thyroid carcinogenesis, and is associated with distinctive morphology and aggressive features even in papillary thyroid microcarcinomas.

[Bethesda classification of fine needle punctures of the thyroid. Much ado about nothing really new?]

The Bethesda system for reporting thyroid cytopathology was published in 2008 (Baloch et al. 2008, Cytojournal 5:6; Baloch et al. 2008, Diagn Cytopathol 36:425-437) offering a classification system which is closely related to clinical data. The aim was to ensure adequate terminology without risk of errors in understanding, to advise clinicians concerning therapeutic options in relationship to cytological diagnoses as well as to facilitate the comparison of cytology data at national and international levels. However, mainly due to specific US American (both medical and legal) demands, this classification system is not yet fully appreciated in most European countries. The reasons are various: (a) Criteria for representative material are much more restrictive than those commonly used and in Germany a higher number of (unnecessary) repunctures would be the consequence. (b) It remains doubtful whether the introduction of a new and rather heterogeneous category of "atypia of undetermined significance or follicular lesion of undetermined significance" would contribute to a substantial decrease of findings classified as "follicular neoplasia". Furthermore it is unlikely that clinicians would be willing to accept the recommended conservative approach with repuncture if a new diagnostic category is associated with a calculated risk of malignancy in 5-15% cases. (c) Until now an integration of new developments in molecular markers into the Bethesda system is missing. Thus, for experienced cytologists the Bethesda system for reporting thyroid cytopathology offers very limited benefits in comparison to the currently used, established and highly accepted classification systems. However, a positive argument remains the fact that an internationally accepted classification system may improve the comparability of the results of national and international studies on thyroid findings.

Prognosis of thyroid nodules in individuals living in the Zhitomir region of Ukraine

Objective

After the accident at the Chernobyl Nuclear Power Plant (CNPP), the incidence of thyroid cancer increased among children. Recently, a strong relationship between solid thyroid nodules and the incidence of thyroid cancer was shown in atomic bomb survivors. To assess the prognosis of benign thyroid nodules in individuals living in the Zhitomir region of Ukraine, around the CNPP, we conducted a follow-up investigation of screening data from 1991 to 2000 in the Ukraine.

Patients and Methods

Participants of this study were 160 inhabitants with thyroid nodules (nodule group) and 160 inhabitants without thyroid nodules (normal control group) intially identified by ultrasonography from 1991 to 2000. All participants were aged 0 to 10 years old and lived in the same area at the time of the accident. We performed follow-up screening of participants and assessed thyroid nodules by fine needle aspiration biopsy.

Results

Among the nodule group participants, the number and size of nodules were significantly increased at the follow-up screening compared with the initial screening. No thyroid nodules were observed among the normal control group participants. The prevalence of thyroid abnormality, especially nodules that could be cancerous (malignant or suspicious by fine needle aspiration biopsy), was 7.5% in the nodule group and 0% in the normal control group (P<0.001).

Conclusions

Our study indicated that a thyroid nodule in childhood is a prognostic factor associated with an increase in the number and size of nodules in individuals living in the Zhitomir region of Ukraine.

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.

Management of thyroid nodules with atypical cytology on fine-needle aspiration biopsy

BACKGROUND

Fine-needle aspiration biopsy (FNAB) of the thyroid categorized as atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) is a newly defined category according to the recent Bethesda guidelines. We sought to assess the characteristics and treatment of patients with an AUS/FLUS FNAB at our institution. Additionally, we evaluated the utility of the recommended 3-month timing of repeat FNAB.

METHODS

A retrospective study of all patients with an FNAB categorized as AUS/FLUS at an academic tertiary-care center. Clinical, cytological, and ultrasound variables were compared among management groups. Differences in patients receiving repeat FNAB before or after a 3-month interval were compared.

RESULTS

A total of 203 patients of the 5,391 FNABs performed at our institution met the Bethesda criteria for AUS/FLUS; 62% were sent directly to surgery, 25% had a repeat FNAB, and 13% were observed. Younger (p=0.006) and male patients (p=0.04) were more likely to go directly to surgery. Microcalcifications, irregular margins, and marked hypoechogenicity on ultrasound did not appear to influence the decision to repeat the FNAB, observe the patient, or refer the patient for surgery. Timing of repeat FNAB (<3 months or ≥3 months) did not alter the diagnostic results of the second FNAB (p=0.73). The overall rate of malignancy in patients undergoing surgery was 15.7%.

CONCLUSIONS

Gender and age, not ultrasound characteristics, appear to influence the decision for surgery in AUS/FLUS patients. Timing of repeat biopsy did not alter management, repeat FNAB diagnosis, or rate of malignancy in our cohort.

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.

Preoperative diagnosis of benign thyroid nodules with indeterminate cytology

BACKGROUND

Approximately 15 to 30% of thyroid nodules evaluated by means of fine-needle aspiration are not clearly benign or malignant. Patients with cytologically indeterminate nodules are often referred for diagnostic surgery, though most of these nodules prove to be benign. A novel diagnostic test that measures the expression of 167 genes has shown promise in improving preoperative risk assessment.

METHODS

We performed a 19-month, prospective, multicenter validation study involving 49 clinical sites, 3789 patients, and 4812 fine-needle aspirates from thyroid nodules 1 cm or larger that required evaluation. We obtained 577 cytologically indeterminate aspirates, 413 of which had corresponding histopathological specimens from excised lesions. Results of a central, blinded histopathological review served as the reference standard. After inclusion criteria were met, a gene-expression classifier was used to test 265 indeterminate nodules in this analysis, and its performance was assessed.

RESULTS

Of the 265 indeterminate nodules, 85 were malignant. The gene-expression classifier correctly identified 78 of the 85 nodules as suspicious (92% sensitivity; 95% confidence interval [CI], 84 to 97), with a specificity of 52% (95% CI, 44 to 59). The negative predictive values for "atypia (or follicular lesion) of undetermined clinical significance," "follicular neoplasm or lesion suspicious for follicular neoplasm," or "suspicious cytologic findings" were 95%, 94%, and 85%, respectively. Analysis of 7 aspirates with false negative results revealed that 6 had a paucity of thyroid follicular cells, suggesting insufficient sampling of the nodule.

CONCLUSIONS

These data suggest consideration of a more conservative approach for most patients with thyroid nodules that are cytologically indeterminate on fine-needle aspiration and benign according to gene-expression classifier results. (Funded by Veracyte.).

Ultrasound-guided fine-needle aspiration biopsy of clinically suspicious thyroid nodules with an automatic aspirator: a novel technique

BACKGROUND

Fine-needle aspiration biopsy (FNAB) is a simple technique for the investigation of suspicious thyroid nodules. However, low success rates are reported in the literature. The aim of this prospective study was to compare the clinical performance and impact of an automatic aspirator, referred to here as Aspirator 3, to those of the manual technique for the FNAB of clinically suspicious thyroid nodules.

METHODS

One hundred nine consecutive patients with 121 clinically suspicious thyroid nodules underwent a biopsy twice of the same site with the clinically approved Aspirator 3 and with the manual technique. The number of follicular cell formations and the total number of follicular cells in the aspirate were counted using the ThinPrep® method.

RESULTS

With the Aspirator 3, the total number and the mean number of extracted cell formations were significantly higher than the values achieved with the manual technique (total: 3222 vs. 1951, p=0.02; mean: 27 vs. 16). The total number of cells that were biopsied was also higher when the Aspirator 3 was utilized (47,480 vs. 23,080, p=0.005). Overall, the Aspirator 3 was superior in 65 biopsies, and the manual technique was superior in 39 biopsies.

CONCLUSIONS

In terms of cell formations and the total number of cells aspirated, the Aspirator 3 was superior to the manual technique. Further, the Aspirator 3 was more convenient to use and had a greater precision in needle guidance.

Cytotechnologist-attended on-site adequacy evaluation of thyroid fine-needle aspiration: comparison with cytopathologists and correlation with the final interpretation

Recent increases in the number of thyroid fine-needle aspiration (FNAs) biopsies and the popularity of on-site evaluation for adequacy (OSEA) have led many practices, including ours, to rely on cytotechnologists for performing OSEA. We retrospectively analyzed the accuracy of a cytotechnologist against that of a cytopathologist in performing OSEA and making the final diagnosis. Of 2,261 thyroid FNA specimens evaluated over a 33-month period under ultrasound guidance with OSEA, the cytotechnologist attended 64.7% (1,462/2,261) of the procedures whereas the cytopathologist attended 35.3% (799/2,261). There was no difference in the adequacy downgrade rate for cytotechnologists compared with that for cytopathologists during this study period (4.1% vs 5.0% downgrade rate, P = .33). Regardless of who rendered the OSEA, subadequate specimens had a higher rate of indeterminate diagnosis (25.2%) than those specimens deemed adequate at the time of OSEA (11.9%, P = .00001). These results indicate that the accuracy of cytotechnologists is comparable with that of cytopathologists in conducting OSEA of the thyroid.

Diagnostic yield of nondiagnostic thyroid nodules is not altered by timing of repeat biopsy

BACKGROUND

Guidelines from the National Cancer Institute Thyroid Fine Needle Aspiration State of the Science Conference recommend a repeat fine-needle aspiration biopsy (FNAB) after 3 months for thyroid nodules with a nondiagnostic (ND) result. Our aims were to assess which factors influenced their clinical management and to determine if the timing of the repeat FNAB affects the diagnostic yield.

METHODS

A retrospective institutional review of 298 patients from 1/2006 to 12/2007 with an ND FNAB was performed. The factors influencing the next step in management, including age, gender, history of radiation, presence of Hashimoto's thyroiditis, thyroid-stimulating hormone levels, and ultrasound characteristics, were evaluated. The effect of the time of the repeat FNABs on their diagnostic yield was assessed.

RESULTS

Of the 298 patients in our cohort, 9% were referred directly for surgery, 76% had a repeat FNAB, and 15% were observed. Tumor size was the only independent variable correlated with treatment strategy after a ND FNAB. There was not a significant difference in diagnostic yields between repeat FNABs performed earlier than 3 months compared to those preformed later (p=0.58).

CONCLUSION

The timing of repeat FNAB for an initial ND FNAB does not affect diagnostic yield of the repeat FNAB.

Nodule or pseudonodule? Differentiation in Hashimoto's thyroiditis with sonoelastography

Fine needle aspiration biopsy (FNAB) is the gold standard for the diagnosis of lymphoma in Hashimoto's thyroiditis and is able to differentiate between benign, inflammatory or malignant nodules, classifying them as either true nodules or pseudonodules. This technique is, however, invasive. The present study aimed to differentiate pseudonodules from true nodules by sonoelastography, a non-invasive technique, in 54 patients with Hashimoto's thyroiditis. The accuracy of sonoelastography to differentiate between true or pseudonodules was compared with the gold standard FNAB and with grey scale ultrasonography. The nodules were categorized into three groups: non-demarcated hypoechogenic, demarcated hyperecho genic, and demarcated hypoechogenic. Sono elastography findings were concordant with the cytopathological results and demonstrated that sono elastography was able to detect true thyroid nodules often misdiagnosed by conventional grey scale ultrasonography. Sonoelastography was found to have increased sensitivity for true nodule diagnosis compared with conventional grey scale ultrasonography and may eliminate unnecessary FNABs being carried out.

Core-needle biopsy is more useful than repeat fine-needle aspiration in thyroid nodules read as nondiagnostic or atypia of undetermined significance by the Bethesda system for reporting thyroid cytopathology

BACKGROUND

Thyroid nodules with fine-needle aspiration (FNA) readings of nondiagnostic or atypia of undetermined significance (AUS), also referred to as follicular lesion of undetermined significance (FLUS) are problematic for their optimal management. The usefulness of performing a core-needle biopsy (CNB) to clarify whether these nodules are benign or malignant has not been established. The purpose of the present study was to determine whether CNB provides better diagnostic information than repeat FNA (rFNA) in thyroid nodules having nondiagnostic or AUS/FLUS readings.

MATERIALS AND METHODS

The Bethesda System for Reporting Thyroid Cytopathology was used for FNA readings and for CNB readings. The study included 225 thyroid nodules from 220 consecutive patients who previously had nondiagnostic (Group N-DIAG, n=64) or AUS/FLUS (Group AF, n=161) FNA readings. All patients simultaneously underwent rFNA and CNB of each nodule. The nondiagnostic and AUS/FLUS readings by rFNA and by CNB were compared. The diagnostic sensitivities of rFNA and CNB for malignancy in thyroid nodules were also assessed. Statistical analysis was performed using a McNemar's test.

RESULTS

In N-DIAG Group, the nondiagnostic readings for the CNBs were lower than that those for rFNAs (1.6% vs. 28.1%, p<0.001). In the AF Group, the AUS/FLUS readings for the CNBs were lower than those for the rFNAs (23.6% vs. 39.8%, p<0.001). The inconclusive diagnoses (nondiagnostic or AUS/FLUS) for the CNBs were lower than those for the rFNAs in Group N-DIAG (12.5% vs. 45.3%, p<0.001) and Group AF (26.7% vs. 49.1%, p<0.001). The sensitivity of CNB for thyroid malignancy was higher than that of rFNA in Group N-DIAG (100% vs. 71.4%, p=0.125) and Group AF (78.5% vs. 55.4%, p<0.001).

CONCLUSION

After patients have had one FNA of a thyroid nodule yielding inconclusive diagnostic results (nondiagnostic or AUS/FLUS), CNB is more useful than rFNA for reducing the frequency of inconclusive diagnostic results. CNB will improve the diagnostic performance for malignancy more than rFNA in thyroid nodules that on the first FNA had nondiagnostic or AUS/FLUS readings.

Ultrasound-guided percutaneous thyroid nodule core biopsy: clinical utility in patients with prior nondiagnostic fine-needle aspirate

BACKGROUND

Five percent to 20% of thyroid nodule fine-needle aspiration (FNA) samples are nondiagnostic. The objective of this study was to determine whether a combination of FNA and core biopsy (CFNACB) would yield a higher proportion of diagnostic readings compared with FNA alone in patients with a history of one or more prior nondiagnostic FNA readings.

METHODS

We conducted a retrospective study of 90 core biopsies (CBs) performed in 82 subjects (55 women and 27 men) between 2006 and 2008 in an outpatient clinic.

RESULTS

CFNACB yielded a diagnostic reading in 87%. The diagnostic reading yield of the CB component of CFNACB was significantly superior to the concurrent FNA component, with CB yielding a diagnosis in 77% of cases and FNA yielding a diagnosis in 47% (p<0.0001). The combination of CB and FNA had a higher diagnostic reading yield than either alone. In 69 nodules that had only one prior nondiagnostic FNA, CB was diagnostic in 74%, FNA was diagnostic in 52%, CFNACB was diagnostic in 87%, and CB performed significantly better than FNA (p=0.0135). In 21 nodules with two or more prior nondiagnostic FNAs, CFNACB and CB were diagnostic in 86%, FNA was diagnostic in 29%, and CB was significantly better than FNA (p=0.0005). Clinical, ultrasound, or histopathologic follow-up was available for 81% (73/90) of the CFNACB procedures. No subject with a benign CFNACB reading was diagnosed with thyroid malignancy in the follow-up period (range 4-37 months, mean 18 months), although one subject had minimal increase in nodule size and was awaiting repeat sonography at study conclusion.

CONCLUSION

Thyroid nodule CFNACB is safe and clinically useful in selected patients when a prior FNA reading is nondiagnostic. CFNACB is superior to either CB or FNA alone. CFNACB should be strongly considered as an alternative to surgery in individuals with two prior nondiagnostic FNAs.

Thyroid fine needle aspirate: a post-Bethesda update

The Bethesda system for reporting thyroid cytopathology formulated in 2007 has standardized reporting of thyroid cytology specimens and streamlined management algorithms. Although 3 of the categories (benign, malignant, and nondiagnostic) are standardized and improved, the remaining 3 (follicular lesion of undetermined significance, follicular neoplasm, and suspicious for malignancy) remain fraught with interobserver variability and uncertainty regarding management algorithms. Recent and ongoing morphologic and molecular studies that aim to resolve these issues are summarized.

Prevalence of malignancy in thyroid nodules with an initial nondiagnostic result after ultrasound guided fine needle aspiration

The objective of this study was to determine the rate of malignancy in thyroid nodules with an initial nondiagnostic fine needle aspiration. From October 2001 to April 2007, biopsies were performed on 1344 thyroid nodules in our practice. Biopsies were performed on nodules using 25-27 gauge needles, ultrasound guidance and multiple passes using both suction and capillary action. We retrospectively reviewed the results of these biopsies as well as any further management of nodules that received nondiagnostic results (IRB HUM00006459). Following initial biopsy, 295/1344 (21.9%) of nodules received nondiagnostic pathologic results. Of this population, 39 nodules (13.1%) were lost to follow-up. Of the remaining 256 nodules that received a repeat FNA, surgical excision, or greater than 24 months of clinical and imaging follow-up, only five cancers were detected, representing only 2% of the population that received an initial nondiagnostic biopsy result. All of these cancers were papillary neoplasms. When rigorous, ultrasound-guided, fine needle aspiration of thyroid nodules is performed, a nondiagnostic histopathologic result should not be interpreted as suspicious for thyroid cancer. Given the low rate of malignancy in this population (2%), we suggest that clinical and imaging follow-up of these nodules, opposed to repeat sampling, is warranted.

Diagnostic accuracy of fine-needle aspiration versus core-needle biopsy for the diagnosis of thyroid malignancy in a clinical cohort

OBJECTIVES

To retrospectively compare the accuracy of fine-needle aspiration (FNA) and core-needle biopsy (CNB) for the diagnosis of thyroid malignancy

METHODS

We evaluated the results of FNA and CNB in 555 consecutive thyroid nodules with final diagnoses (malignancy 318, benign 237). All patients underwent FNA and CNB simultaneously for each nodule. We assessed the sensitivity, specificity and accuracy of FNA, CNB and FNA/CNB for the diagnosis of thyroid malignancy.

RESULTS

The sensitivity of FNA, CNB and FNA/CNB for thyroid malignancy was 68.6%, 86.8% and 90.6%, specificity 100%, 99.2% and 99.2%, and accuracy 82.0%, 92.1% and 94.2%, respectively. The sensitivity and accuracy of CNB or FNA/CNB for thyroid malignancy were significantly higher than those of FNA (P < 0.001). Compared with CNB alone, FNA/CNB was more accurate for thyroid malignancy only in small nodules less than 1 cm (P < 0.001).

CONCLUSIONS

Our clinical cohort data demonstrated that CNB was more accurate for the diagnosis of thyroid malignancy than FNA, and FNA/CNB was more accurate than CNB alone in small thyroid nodules. CNB will play a complementary role in optimal surgical decision-making and the management of thyroid nodules.

KEY POINTS

• CNB was more accurate for the diagnosis of malignancy than FNA. • Combined FNA/CNB was more accurate than CNB alone in small thyroid nodules. • CNB should play at least a complementary role in managing thyroid nodules.

The Bethesda System thyroid diagnostic categories in the African-American population in conjunction with surgical pathology follow-up

Background:

It has been reported that African-Americans (AA) have a higher prevalence of overall malignancy compared to Caucasians, in the United States, yet the incidence of thyroid malignancy is half. The aim of this study is to assess the rate of malignant versus benign thyroid disease in AA from an urban-based hospital with an academic setting. Our study analyzed the AA population with respect to fine needle aspiration (FNA) of thyroid lesions, in correlation with final surgical pathology. This is the first study of its kind to our knowledge.

Design:

We retrospectively reviewed thyroid FNA cytology between January 2005 and February 2011. Consecutive FNA specimens with corresponding follow-up surgical pathology were included. The patients were categorized as African- American (AA) and Non-African-American (NAA), which included Caucasians (C), Hispanics (H), and Others (O). The FNA results were classified using the latest edition of The Bethesda System for Reporting Thyroid Cytopathology (TBS-Thy) and the follow-up surgical pathology was used for the final categorization.

Results:

We studied 258 cases: 144 AA (56%) and 114 NAA [43 C (17%), 3 H (1%), and 68 O (28%)]. The average age for AA was 51 years (range 20 – 88) and for NAA was 53 years (range 25 – 86). There were more females than males in the AA versus the NAA group (85 vs. 75%). The incidence of thyroid lesions in the FNA specimens was similar between these two populations. The distribution of benign versus malignant diagnosis on follow-up surgical pathology was examined across TBS-Thy class.

Conclusion:

Our data suggest that distribution of benign versus malignant lesions in the thyroid FNA of AA versus NAA, with follow-up surgical pathology, is comparable for TBS-Thy classes, non-diagnostic (I), benign (II), suspicious for malignancy (V), and malignant (VI) in AA versus NAA.

Three-gene molecular diagnostic model for thyroid cancer

BACKGROUND

The preoperative diagnosis of thyroid nodules primarily depends upon fine needle aspiration (FNA) cytology. However, up to 25% of FNA samples have associated "suspicious or indeterminate", but not diagnostic cytologic reports, resulting in difficulty deciding appropriate clinical management for these patients. We hypothesize that the use of molecular markers as an adjunct to FNA cytology can improve the distinction of benign from malignant nodules that have associated suspicious or indeterminate cytology.

METHODS

Using microarray analysis, we previously identified and reported on 75 genes useful in the distinction of benign versus malignant thyroid nodules. In the present study, we have further validated the expression of 14 of these markers in a large number of thyroid samples by immunohistochemistry (IHC) analysis of 154 thyroid tumors and quantitative real-time RT-PCR (QRT-PCR) analysis of 95 FNA samples. Of the 154 tumors analyzed by IHC, 44 samples (29%) had associated suspicious or indeterminate FNA cytology.

RESULTS

Receiver operating characteristic using three-gene model, (HMGA2, MRC2, and SFN) analysis for the detection of malignant nodules resulted in areas under the curve (AUCs) of≥0.95 (80% sensitivity; 100% specificity) and≥0.84 (71% sensitivity; 84% specificity) for the IHC data in tumors, and QRT-PCR data in FNA samples, respectively.

CONCLUSIONS

Our results suggest that a three-gene model for the cytological diagnosis of indeterminate thyroid nodules is both feasible and promising. Implementation of this as an adjunct to thyroid cytology may significantly impact the clinical management of patients with suspicious or indeterminate thyroid FNA nodules.

Papillary thyroid carcinomas with and without BRAF V600E mutations are morphologically distinct

AIMS

  The BRAF V600E mutation resulting in the production of an abnormal BRAF protein has emerged as the most frequent genetic alteration in papillary thyroid carcinomas (PTCs). This study was aimed at identifying distinctive features in tumours with and without the mutation.

METHODS AND RESULTS

  Thirty-four mutation-positive and 22 mutation-negative tumours were identified by single-strand conformation polymorphism of the amplified BRAF V600E region in the tumour DNA. Mutation-positive tumours were more common in patients older than 45 years (24/33, P = 0.05), in classic (23/30, P = 0.01), tall cell (4/5) and oncocytic/Warthin-like (2/2) variants of PTC, and in subcapsular sclerosing microcarcinomas (4/4). In contrast, all 12 follicular variants (P < 0.0001) and two diffuse sclerosing variants were negative for the mutation. Mutation-positive tumours displayed infiltrative growth (32/34, P = 0.02), stromal fibrosis (33/34, P < 0.001), psammoma bodies (17/34, P = 0.05), plump eosinophilic tumour cells (22/34, P = 0.01), and classic fully developed nuclear features of PTC (33/34, P = 0.0001). Encapsulation was significantly associated with mutation-negative tumours (15/22, P = 0.02).

CONCLUSIONS

  BRAF V600E mutation-positive and negative PTCs are morphologically different. Recognition of their morphology may help in the selection of appropriate tumours for genetic testing.

Tract recurrence of a follicular thyroid neoplasm following transaxillary endoscopic thyroidectomy

BACKGROUND

Endoscopic thyroidectomy is gaining popularity, particularly in Asian countries, as an alternative to conventional cervical thyroidectomy. Multiple large case series have been published that confirm the feasibility and safety of this procedure compared to conventional methods. However, no data are available that demonstrate long-term oncologic outcomes or complications.

PATIENT FINDINGS

A patient who underwent transaxillary gas insufflation thyroidectomy for a follicular neoplasm presented to the authors with a mass along the operative tract 31 months after her first surgery. The mass was found to be a recurrence of the thyroid neoplasm.

SUMMARY

Since this is a relatively new procedure, the potential complications differ from those of conventional cervical thyroidectomy. Further studies are needed to determine size limitations on nodules considered for endoscopic resection.

CONCLUSION

When performing these procedures, care should be taken to ensure that the specimen is removed entirely and in one piece. Long-term outcomes data for endoscopic thyroidectomy are warranted prior to this becoming an acceptable standard of care for thyroid surgery.

Utility and interobserver agreement of ultrasound elastography in the detection of malignant thyroid nodules in clinical care

BACKGROUND AND PURPOSE

Malignancy correlates with hardness of tissues and US elastography can potentially analyze the stiffness of lesions. Our aim was to evaluate the utility of US elastography in the detection of malignant nodules and to investigate interobserver agreement with this technique.

MATERIALS AND METHODS

One-hundred three consecutive patients with 106 thyroid nodules were examined prospectively with conventional B-mode sonography and real-time US elastography. All patients were referred for FNAB. Conventional B-mode sonography and US elastographic examinations were performed, and images were separated and independently interpreted by 2 radiologists blinded to pathologic results. US elastogram evaluation was based on a simplified classification of stiffness based on gray-scale patterns, tumor size compared with B-mode, and margins. Interobserver agreement was studied. FNAB was used as the reference standard for the diagnosis of benign nodules, but histopathologic evaluations were performed when results suspicious for malignancy or malignant results were obtained on FNAB as well as in indeterminate lesions.

RESULTS

In our study, pattern of stiffness based on gray-scale and classification proposed were statistically significant and predicted malignancy with 100% sensitivity and 40.6% specificity. Tumor size when compared with B-mode images or margins was not statistically significant in our study. No false-negatives were found, and an NPV of 100% was seen. Interobserver agreement for US elastography was excellent in our study, with a κ index of 0.82 (95% CI).

CONCLUSIONS

We believe that US elastography is a promising technique that can assist in the evaluation of thyroid nodules and can potentially diminish the number of FNAB procedures needed. We believe that it may be useful to introduce US elastography into routine clinical practice.

Malignancy rate in nondominant nodules in patients with multinodular goiter: Experience with 1,606 cases evaluated by ultrasound-guided fine needle aspiration cytology

Background:

Conventional medical sources recommend the use of fine needle aspiration cytology (FNAC) for single thyroid nodules and the dominant nodule in multinodular goiter (MNG). The purpose of the present study was to analyze the utility of FNAC for multiple thyroid nodules in patients with MNG and to determine the rate of malignancy in teh nondominant nodules.

Materials and Methods:

Our private practice performed ultrasound-guided FNAC on 1,606 patients between February 2001 and February 1, 2010. In the MNG cases, samples were taken from the dominant nodule and from trhee suspicious / nonsuspicious nodules larger than 1 cm on ultrasound. Ninety-four cases were diagnosed as ‘suspiciously malignant’(SUS) or ‘malignant’ (POS) based on FNAC.

Results:

The rate of an SUS / POS diagnosis was 5.7% in the dominant nodules; 2.3% of the nondominant nodules had a SUS / POS diagnosis in FNAC (p = 0.0003). Follow-up revealed malignancy in 15 (35.7%) nondominant nodules and in 27 (64.2%) dominant nodules, with 42 MNG cases undergoing surgery. X test showed a ‘p-level of 0.0003’ between the percentages of SUS / POS diagnosis in dominanat and nondominanat nodules. It was less than the significance level of 0.05. Therefore, the result was regarded to be statistically significant.

Conclusions:

Nondominant nodules could harbor malignancy. The risk of malignancy in nondominant nodules in MNG should not be underestimated. We have shown that the dominant nodule in patients with MNG was in fact about 2.5 times more likely to be malignant than a nondominant nodule. The use of FNAC for nondominant nodules could enhance the likelihood of detecting malignancy in an MNG.

The role of preoperative neck ultrasounds to assess lymph nodes in patients with suspicious or indeterminate thyroid nodules

BACKGROUND AND OBJECTIVES

Currently there are no recommendations for obtaining a preoperative neck ultrasound for patients with suspicious or indeterminate thyroid nodules. Because a preoperative surgical ultrasound can detect suspicious lymph nodes that could result in ultimately altering surgical management, we chose to study which variables were predictive of this change.

METHODS

Medical records of 173 patients who presented between January 2006 and December 2010 with suspicious or indeterminate thyroid cytology were retrospectively reviewed. Clinicopathological variables were analyzed to determine factors predictive of malignancy and a change in operative approach.

RESULTS

One hundred thirty-four of 173 patients were evaluable. Seventeen of 134 (12.6%) of the preoperative ultrasounds were suspicious. Seven of 134 (5.2%) patients underwent a formal lymph node dissection based on ultrasound findings. Size of tumor, Bethesda FNAB category, and male gender were associated with malignancy while thyroid nodule microcalcifications and category of FNAB were associated with performing lymph node dissections.

CONCLUSION

Thyroid nodule microcalcifications on ultrasound and category of FNAB appear to be the best predictors of metastatic disease. Because the surgical approach was altered in only a few patients, further analysis is needed to delineate whether performing cervical ultrasound for suspicious/indeterminate nodules is cost effective.

Usefulness of diagnostic qualifiers for thyroid fine-needle aspirations with atypia of undetermined significance

The diagnostic category of atypia of undetermined significance (AUS) in the Bethesda System for reporting the results of thyroid fine-needle aspirations (FNAs) is intended to encompass findings associated with a low risk of malignancy. It is unclear if there are patterns within this evolving, heterogeneous category associated with differing risk of malignancy that might warrant alternative classification or clinical management. Therefore, a retrospective review of 512 AUS FNAs from January 2005 to May 2009 was done. Most malignancies associated with AUS were papillary carcinoma (86/96 [90%]), of which 85% (73/86) were follicular variants. Atypia qualifiers were correlated with the follow-up rate of malignancy. The risk of malignancy for architectural atypia alone was approximately half that observed for cytologic, both cytologic and architectural, or unspecified atypia. Architectural atypia alone was less likely to be papillary carcinoma and more likely to be follicular adenoma. The lower risk of malignancy associated with isolated architectural atypia compared with other patterns of AUS should be considered in clinical decision making and in future management guidelines.

Pyrosequencing cut-off value identifying BRAFV600E mutation in fine needle aspiration samples of thyroid nodules

CONTEXT

Recently, tremendous efforts have been made towards the development of sensitive techniques to detect the BRAF(V600E) mutation in fine needle aspiration biopsy (FNAB) samples. However, newly developed quantitative and semi-quantitative methods, such as dual-priming oligonucleotide (DPO)-based multiplex polymerase chain reaction (PCR), have the potential to generate false-positive (FP) results.

OBJECTIVES

To eliminate the possibility of FP results, we generated a receiver operating characteristic (ROC) curve to investigate the diagnostic accuracy of pyrosequencing using quantitative data.

DESIGN

Cytological diagnoses of 983 thyroid nodules were made according to the Bethesda System 2007. The BRAF(V600E) mutation was analysed by pyrosequencing, and statistical analyses were performed.

RESULTS

Of the 983 nodules, 902 were adopted to evaluate the diagnostic value of pyrosequencing. The number of pathologically confirmed malignancies was 192, of which 182 were papillary thyroid cancer (PTC). By generating an ROC curve, we defined the optimal cut-off value of the mutant allele peak as 5·95% (area under the curve, 0·849; sensitivity, 0·55; 1-specificity, 0). When we applied this selective cut-off value, the number of PTCs positive for BRAF(V600E) was 99 (54·4% of the total number of PTCs). With cytology alone, the diagnostic sensitivity and specificity of detecting malignancy were 71·2% and 100%, respectively. Pyrosequencing improved the diagnostic sensitivity from 71·2% to 78·5% (McNemar's test, P < 0·001), without any change in the diagnostic specificity. When 'suspicious for malignancy' was considered a positive cytological outcome, pyrosequencing increased the diagnostic sensitivity of cytology from 95·8% to 96·9%; however, this improvement did not show statistical significance (McNemar's test, P > 0·05).

CONCLUSIONS

Pyrosequencing is an effective method for detecting the BRAF(V600E) mutation in FNAB samples. By allowing the optimal cut-off value to be determined, pyrosequencing improves the diagnostic sensitivity while eliminating the possibility of FP results.