Accuracy of fine-needle aspiration biopsy for predicting neoplasm or carcinoma in thyroid nodules 4 cm or larger

The impact of nodule size on malignancy risk in indeterminate thyroid nodules

Background

The association between malignancy risk and nodule size in indeterminate thyroid nodules (ITNs) remains controversial. Thus, we aimed to explore the impact of nodule size as a predictor of cancer in patients with ITNs.

Methods

This cross-sectional study assessed 113 patients who underwent surgical intervention for ITNs, comparing two groups based on nodule size (≥4 or <4 cm). The correlation between nodule size and malignancy risk was examined. Other variables of interest included demographics, thyroid-stimulating hormone (TSH) levels, type of surgery, and ultrasound features.

Results

Of the 113 patients, 88.5% were aged <55 years, 76.1% were women, and 65.5% had nodules <4 cm. Mean nodule size was 3.4±2.3 cm. There was no significant correlation between malignancy risk and nodule size (P=0.55). An association was observed between <4 cm nodules and elevated TSH levels (P=0.03) and between ≥4 cm nodules and the presence of hypervascularity (P=0.04). Nodules <4 cm were more likely to have extrathyroidal extension, lymphovascular invasion, and positive margins than those ≥4 cm; however, this was not significant.

Conclusions

Our findings showed no association between nodule size and malignancy risk, suggesting that size alone is not a predictor of cancer development. Further prospective studies are required to confirm these results.

Do large thyroid nodules (≥4 cm) without suspicious cytology need surgery?

Background

Fine-needle aspiration biopsy (FNAB) is a good diagnostic tool for thyroid nodules; however, its high false-negative rate for giant nodules remains controversial. Many clinicians recommend surgical resection for nodules >4 cm owing to an increased risk of malignancy and an increased false-negative rate. This study aimed to examine the feasibility of this approach and investigate the incidence of malignancy in thyroid nodules >4 cm without suspicious cytology based on medical records in our center.

Methods

This was a retrospective analysis of 453 patients that underwent preoperative FNAB for nodules measuring >4 cm between January 2017 and August 2022 at Severance Hospital, Seoul.

Results

Among the 453 patients, 140 nodules were benign and 119 were indeterminate. Among 259 patients, the final pathology results were divided into benign (149) and cancerous (110) groups, and the prevalence of malignancy was 38.9% in the benign group and 55.5% in the indeterminate group. Among the malignancies, follicular carcinoma and follicular variants of papillary carcinoma were observed in 83% of the cytologically benign group and 62.8% of the indeterminate group.

Conclusion

Preoperative FNAB had high false-negative rates and low diagnostic accuracy in patients with thyroid nodules >4 cm without suspicious cytologic features; therefore, diagnostic surgery may be considered a treatment option.

Comparative analysis of accuracy between fine-needle aspiration biopsy and postoperative histopathology for detecting large thyroid nodules: A retrospective observational study

To avoid unnecessary surgeries, ultrasound-guided fine-needle aspiration biopsy (FNAB) is an effective and reliable procedure for the preoperative evaluation of thyroid nodules. However, there have been only a limited number of studies exploring the ability of preoperative FNAB to distinguish malignancy compared to postoperative histopathology in thyroid nodules larger than 4 cm. The aim of this study was to investigate the diagnostic accuracy of FNAB compared to postoperative histopathology in distinguishing malignancy in thyroid nodules larger than 4 cm. A single-center retrospective observational study was conducted at Dr. Zainoel Abidin Hospital, Banda Aceh, Indonesia, between January 2014 and December 2018. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were calculated. A total of 83 patients were included in the study. The results showed that preoperative FNAB may have the ability to distinguish malignancy compared to postoperative histopathology. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 42.85%, 98.38%, 90.00%, 83.56%, and 84.33%, respectively. These data suggested that ultrasound-guided preoperative FNAB is a reliable diagnostic tool in the preoperative evaluation of thyroid nodules larger than 4 cm, but it has limited capability in distinguishing malignancies. In conclusion, although FNAB may be useful in reducing unnecessary surgeries, histopathology remains the preferred method for confirming malignancy in thyroid nodules.

Risk of malignancy and diagnostic accuracy of fine-needle aspiration biopsy in thyroid nodules with diameters greater than 4 centimeters

Objective

The risk of malignancy and diagnostic accuracy of fine-needle aspiration biopsy (FNAB) of thyroid nodules (TN) with diameters ≥ 3-4 cm remains controversial. However, some groups have indicated surgical treatment in these patients regardless of the FNAB results. We aimed to evaluate the diagnostic accuracy of the FNAB in systematically resected ≥4 cm TN and if the risk of malignancy is higher in these patients.

Subjects and methods

We retrospectively evaluated 138 patients (142 nodules) with TN with diameters ≥4 cm who underwent thyroidectomy.

Results

The FNAB results were nondiagnostic/unsatisfactory (ND/UNS) in 2.1% of the cases and benign in 51.4%. They indicated atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) in 23.9% of cases, follicular neoplasia/suspicious for a follicular neoplasm (FN/SFN) in 9.2%, suspicion of malignancy (SUS) in 8.5%, and malignant in 4.9%. The histopathological analysis after thyroidectomy revealed a thyroid cancer rate of 100% in the FNABs classified as malignant, 33.3% in SUS cases, 7.7% in FN/SFN, 17.6% in AUS/FLUS, and 4.1% in benign FNABs. None of the ND/UNS FNABs were malignant. The global malignancy diagnosis was 14.8% (n = 21). However, the rate of false negatives for FNAB was low (4.1%).

Conclusion

We showed that the risk of malignancy in nodules with diameters ≥4 cm was higher compared to the risk of thyroid cancer in TN in general. However, we found a low rate of false-negative cytological results; therefore, our data do not justify the orientation of routine resection for these larger nodules.

Comparison of fine-needle aspiration with fine-needle capillary cytology in thyroid nodules

INTRODUCTION

High false-negative results have been reported for fine-needle aspiration (FNA) cytology in thyroid nodules. Fine-needle capillary (FNC) cytology is an alternative technique that prevents aspiration, reducing tissue damage. This study aimed to compare FNA and FNC in assessing thyroid nodules and in terms of their predictive role in the appropriate diagnosis of malignancy.

METHODS

This is a comparative prospective study conducted on 486 patients. FNA was performed in 235 patients during 2016 and 2017 and FNC in 251 patients during 2018 and 2019. The quality of cytological specimens was compared and then correlated with the final histopathological findings of 39 patients who underwent thyroidectomy.

RESULTS

Both groups were statistically similar regarding age and sex distribution. The FNA technique yielded significantly higher adequate specimens compared with FNC (p<0.001). Abundant blood in the background was found more frequently in the FNA technique (p<0.001). The sensitivity and specificity of FNA for malignancy diagnosis were both 100%, compared with 83.3% and 57.7% for FNC, respectively.

CONCLUSIONS

The two methods, FNA and FNC, did not differ in terms of overall quality. FNA was superior regarding consistency with the histopathological results and the ability to diagnose malignancy.

Molecular Testing for Indeterminate Thyroid Nodules: Association of Negative Predictive Value With Nodule Size

BACKGROUND

Molecular testing helps stratify risk of malignancy in indeterminate thyroid nodules, but it may be limited in its ability to rule out malignancy in large nodules.

METHODS

We compared small thyroid nodules (<4 cm) to large thyroid nodules (4 cm or greater) in a retrospective, single center, cohort study of indeterminate thyroid nodules analyzed with ThyroSeq from 10/2015 through 4/2020. Our primary outcome was negative predictive value.

RESULTS

A total of 204 thyroid nodules were analyzed with ThyroSeq and 62 underwent resection allowing comparison to final pathology for 48 small nodules and 14 large nodules. A greater proportion of large nodules were observed in men (50.0% vs 18.8% in small nodules, P = .02), but median age was similar between the groups (49.0 vs 52.5 years, P = .95). False negative results comprised a higher proportion of tests for large nodules (14.3%) than small nodules (0%, P = .01). The negative predictive value of ThyroSeq in small nodules was 1 indicating a negative test reliably predicted a benign nodule, compared to .5 in large nodules indicating a negative test in this cohort was reliable in predicting benignity. Applying the same negative predictive value to the cohort of large nodules that did not undergo resection after negative molecular testing (n = 16), it is possible that 8 large thyroid malignancies were missed at our institution during the study period.

CONCLUSIONS

Large thyroid nodules are associated with a higher rate of false negative results and a lower negative predictive value during molecular analysis of indeterminate thyroid nodules.

Ultrasound classification of thyroid nodules: does size matter?

Objective

To determine whether the size of thyroid nodules in ACR-TIRADS ultrasound categories 3 and 4 is correlated with the Bethesda cytopathology classification.

Methods

Thyroid nodules (566) subclassified as ACR-TIRADS 3 or 4 were divided into three size categories according to American Thyroid Association guidelines. The frequency of different Bethesda categories in each size range within ACR-TIRADS 3 and 4 classifications was analyzed.

Results

Most nodules in both ACR-TIRADS classifications fell in the Bethesda 2 category, regardless of size (90.8% and 68.6%, ACR-TIRADS 3 and 4 respectively). The prevalence of Bethesda 6 nodules in the ACR-TIRADS 4 group was 14 times higher than in the ACR-TIRADS 3 group. There were no significant differences between nodule size and fine needle aspiration biopsy classification in any of the ACR-TIRADS categories.

Conclusion

Size does not appear to be an important criterion for indication of fine needle aspiration biopsy in thyroid nodules with a high suspicion of malignancy on ultrasound examination.

Fine Needle Aspiration Cytology vs. Core Needle Biopsy for Thyroid Nodules: A Prospective, Experimental Study Using Surgical Specimen

PURPOSE

To evaluate and compare the diagnostic outcomes of ultrasonography (US)-guided fine needle aspiration (FNA) and core needle biopsy (CNB) performed on the same thyroid nodule using a surgical specimen for direct comparison.

MATERIALS AND METHODS

We included 89 thyroid nodules from 88 patients from February 2015 to January 2016. The inclusion criterion was thyroid nodules measuring ≥ 20 mm (mean size: 40.0 ± 15.3 mm). Immediately after surgical resection, FNA and subsequent CNB were performed on the surgical specimen under US guidance. FNA and CNB cytopathologic results on the specimen were compared with the surgical diagnosis.

RESULTS

Among the 89 nodules, 30 were malignant and 59 were benign. Significantly higher inconclusive rates were seen in FNA for malignant than benign nodules (80.0% vs. 39.0%, p < 0.001). For CNB, conclusive and inconclusive rates did not differ between benign and malignant nodules (p = 0.796). Higher inconclusive rates were seen for FNA among cancers regardless of US features, and in the subgroup of size ≥ 40 mm (62.5% vs. 22.9%, p = 0.028). Eleven cancers were diagnosed with CNB (36.7%, 11/30), while none was diagnosed using FNA.

CONCLUSION

In this experimental study using surgical specimens, CNB showed a potential to provide improved diagnostic sensitivity for thyroid cancer, especially when a conclusive diagnosis is limited with FNA.

Navigating the Debate on Managing Large (≥4 cm) Thyroid Nodules

PURPOSE

Discordant practice guidelines for managing large thyroid nodules may result in unnecessary surgeries and costs. Recent data suggest similar false-negative rates in fine needle aspiration (FNA) biopsies between small (<4 cm) and large (≥4 cm) nodules, indicating that monitoring rather than surgery may be appropriate for large biopsy-negative nodules. We investigated the management of thyroid nodules ≥4 cm to determine the proportion of surgeries not necessary for diagnostic purposes and examined for potential predictors.

METHODS

This was a retrospective cohort study of patients who received a FNA of nodule(s) ≥4 cm between 11/1/2014 and 10/31/2019 at the University of Vermont Medical Center. A surgery was considered unnecessary if the FNA result was benign in the absence of any of the following: compressive symptoms, family history of thyroid cancer in a first degree relative, history of neck irradiation, toxic nodule or toxic multinodular goiter, or substernal extension. Data were analyzed with Wilcoxon rank sum tests, chi square, or Fisher's exact tests.

RESULTS

177 patients had a ≥4 cm nodule during the timeframe and half (54.2%) had surgery. Patients who underwent surgery were significantly younger (51.5 years vs. 62 years; P < 0.001), more likely to report obstructive symptoms (34.4% vs. 12.1%; P < 0.001) and had a larger nodule size (5.0 cm vs. 4.7 cm; P=0.26). Forty-one patients with benign (Bethesda II) FNA results had surgery, all with negative surgical pathology. Thirteen percentage (23/177) of surgeries were potentially not necessary for diagnostic purposes.

CONCLUSION

Approximately half of our patients with ≥4 cm nodules had surgery, with 13% having surgery not necessary for diagnostic purposes revealing opportunities for improving care and costs.

Long-term outcomes of cytologically benign thyroid tumors: a retrospective analysis of 3,102 patients at a single institution

Some thyroid tumors that are cytologically diagnosed as benign may be pathologically diagnosed as malignant. Here, we investigated the long-term outcomes of patients with thyroid tumors with benign cytology, and the factors for malignancy. We retrospectively reviewed the cases of 3,102 patients with thyroid tumors >1 cm cytologically diagnosed as benign at our hospital during a 1-year period from January 2007. The median follow-up duration for all patients was 68.7 (range 0.0-168.7) months. Immediate surgery and delayed surgery were performed in 393 and 148 patients, respectively. Eventually, 541 (17.4%) of the 3,102 patients underwent a thyroidectomy, and 2,561 (82.6%) were observed without surgery. Among the surgically treated patients, the tumors of 525 (97.0%) and 16 (3.0%) were pathologically diagnosed as benign and malignant, respectively. There was no significant difference in age, gender, tumor size, serum thyroglobulin level at surgery, or the tumor volume-doubling rate (TV-DR) between the benign and malignant cases. Only the ultrasonographic findings based on our hospital's classification system were directly and significantly linked to pathological diagnosis (p < 0.01). Among the tumors of the 667 patients who were followed without surgery for >10 years, 89.9% remained unchanged and 7.2% were reduced in size. Ultrasonographic evaluation provides important information for therapeutic decision-making regarding surgery versus observation for cytologically benign tumors.

2021 Korean Thyroid Imaging Reporting and Data System and Imaging-Based Management of Thyroid Nodules: Korean Society of Thyroid Radiology Consensus Statement and Recommendations

Incidental thyroid nodules are commonly detected on ultrasonography (US). This has contributed to the rapidly rising incidence of low-risk papillary thyroid carcinoma over the last 20 years. The appropriate diagnosis and management of these patients is based on the risk factors related to the patients as well as the thyroid nodules. The Korean Society of Thyroid Radiology (KSThR) published consensus recommendations for US-based management of thyroid nodules in 2011 and revised them in 2016. These guidelines have been used as the standard guidelines in Korea. However, recent advances in the diagnosis and management of thyroid nodules have necessitated the revision of the original recommendations. The task force of the KSThR has revised the Korean Thyroid Imaging Reporting and Data System and recommendations for US lexicon, biopsy criteria, US criteria of extrathyroidal extension, optimal thyroid computed tomography protocol, and US follow-up of thyroid nodules before and after biopsy. The biopsy criteria were revised to reduce unnecessary biopsies for benign nodules while maintaining an appropriate sensitivity for the detection of malignant tumors in small (1-2 cm) thyroid nodules. The goal of these recommendations is to provide the optimal scientific evidence and expert opinion consensus regarding US-based diagnosis and management of thyroid nodules.

Current Evaluation of Thyroid Nodules

Thyroid nodules may be discovered in a variety of settings. Familiarity with their management is important for medical specialists. Workup should start with history and physical examination, proceed to laboratory studies, and then to imaging. Nodules are selected for fine needle aspiration (FNA) biopsy based on imaging criteria. Most nodules can be accurately diagnosed on cytopathology, but some may require additional molecular testing to evaluate risk of malignancy. Patients with malignant lesions require additional investigation before referral to an experienced thyroid surgeon. Those who have benign lesions may require monitoring by periodic ultrasound to identify nodules requiring reevaluation.

Suspicious thyroid nodules ≥4 cm require diagnostic lobectomy regardless of their benign fine needle aspiration results

BACKGROUND/OBJECTIVE

The diagnostic accuracy of fine needle aspiration biopsy (FNAB) seems limited in large thyroid nodules with Bethesda Cat. 2 result. We aimed to determine the incidence of carcinoma with benign cytology and the reason for the high false-positive rate in thyroid nodules ≥4 cm.

METHODS

The records of 103 patients with thyroid nodules ≥4 cm with preoperative cytological diagnosis of Bethesda Cat. 2 who underwent thyroidectomy were consecutively reviewed. Characteristics between patients with malignant vs. benign pathology were compared.

RESULTS

Forty patients (38.8%) had malignancy. Malignancy was subclassified into follicular variant of papillary thyroid carcinoma (43%), minimally invasive follicular thyroid carcinoma (20.0%), and minimally invasive Hurthle cell thyroid carcinoma (10.9%). Patients with malignant cytology had significantly more suspicious ultrasound findings than those with benign cytology (p = 0.001).

CONCLUSIONS

Preoperative FNAB showed high false-negative rates in patients with thyroid nodules ≥4 cm with benign cytology. These nodules have a high malignancy rate with suspicious ultrasound findings.

Diagnostic performance rates of the ACR-TIRADS and EU-TIRADS based on histopathological evidence

PURPOSE

In this study, we aimed to assess the effectiveness of malignancy stratification algorithms of the American College of Radiology (ACR) and European Thyroid Association (ETA) in the delineation of thyroid nodules using a database of nodules that were unequivocally diagnosed by means of histopathological examination and meticulously matched with the imaged nodules.

METHODS

A total of 165 patients having 251 thyroid nodules with histopathologically proven definitive diagnoses during a 5-year period were included in this study. All patients had preoperatively undergone ultrasonography (US) examination, and US characteristics of the thyroid nodules were retrospectively analyzed and assigned in compliance with the thyroid imaging reporting and data system categories recommended by the ACR (ACR-TIRADS) and ETA (EU-TIRADS). The diagnostic effectiveness in the delineation of thyroid nodules and unnecessary fine-needle aspiration (FNAB) rates were evaluated.

RESULTS

Overall, 189 nodules (75.30%) were diagnosed as benign, while 62 nodules (24.70%) were reported to be malignant based on histopathological assessment. Sensitivity and specificity rates were 71% and 75% for ACR-TIRADS and 73% and 80% for EU-TIRADS. The area under the curve values were 0.78 and 0.80 for ACR-TIRADS and EU-TIRADS, respectively. The unnecessary FNAB rates were 61% for ACR-TIRADS and 64% for EU-TIRADS as per the recommended criteria of each algorithm.

CONCLUSION

The diagnostic performance of both malignancy stratification systems was signified to be moderate and sufficient in a cohort of nodules with definite histopathological diagnosis. In light of our results, we demonstrated the strengths and weaknesses of the ACR- and EU-TIRADS for physicians who should be familiar with them for optimal management of thyroid nodules.

Establishment of an Ultrasound Malignancy Risk Stratification Model for Thyroid Nodules Larger Than 4 cm

Background

The incidence and mortality of thyroid cancer, including thyroid nodules > 4 cm, have been increasing in recent years. The current evaluation methods are based mostly on studies of patients with thyroid nodules < 4 cm. The aim of the current study was to establish a risk stratification model to predict risk of malignancy in thyroid nodules > 4 cm.

Methods

A total of 279 thyroid nodules > 4 cm in 267 patients were retrospectively analyzed. Nodules were randomly assigned to a training dataset (n = 140) and a validation dataset (n = 139). Multivariable logistic regression analysis was applied to establish a nomogram. The risk stratification of thyroid nodules > 4 cm was established according to the nomogram. The diagnostic performance of the model was evaluated and compared with the American College Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS), Kwak TI-RADS and 2015 ATA guidelines using the area under the receiver operating characteristic curve (AUC).

Results

The analysis included 279 nodules (267 patients, 50.6 ± 13.2 years): 229 were benign and 50 were malignant. Multivariate regression revealed microcalcification, solid mass, ill-defined border and hypoechogenicity as independent risk factors. Based on the four factors, a risk stratified clinical model was developed for evaluating nodules > 4 cm, which includes three categories: high risk (risk value = 0.8-0.9, with more than 3 factors), intermediate risk (risk value = 0.3-0.7, with 2 factors or microcalcification) and low risk (risk value = 0.1-0.2, with 1 factor except microcalcification). In the validation dataset, the malignancy rate of thyroid nodules > 4 cm that were classified as high risk was 88.9%; as intermediate risk, 35.7%; and as low risk, 6.9%. The new model showed greater AUC than ACR TI-RADS (0.897 vs. 0.855, p = 0.040), but similar sensitivity (61.9% vs. 57.1%, p = 0.480) and specificity (91.5% vs. 93.2%, p = 0.680).

Conclusion

Microcalcification, solid mass, ill-defined border and hypoechogenicity on ultrasound may be signs of malignancy in thyroid nodules > 4 cm. A risk stratification model for nodules > 4 cm may show better diagnostic performance than ACR TI-RADS, which may lead to better preoperative decision-making.

False positive cases in thyroid cytopathology - the experience of a single laboratory and a systematic review

INTRODUCTION

Fine needle aspiration (FNA) is fundamental in the pre-operative assessment of thyroid nodules. However, the shining success of thyroid FNA is occasionally eclipsed by false positive (FP) cytological diagnoses. We describe our experience regarding FP cytological diagnoses and present a literature review concerning FP rates.

MATERIALS AND METHODS

We retrospectively analyzed 2031 consecutive cytology reports. FP was defined as a case with "suspicious for malignancy" or "malignant" cytology, whose surgical follow-up failed to confirm the initial diagnosis of malignancy. We used the PubMed database for the literature review using specific search terms ("thyroid", "cytology", "false positive").

RESULTS

Out of 2031 FNA reports, 93 cases with "suspicious for malignancy" or "malignant" cytology underwent surgical excision. Histopathology did not confirm malignancy in 10 cases (0.6% FP rate). Nodules with FP cytology were significantly larger (P = 0.0024) than those with with TP (true positive) cytology. A review of 25 publications shows comparable results to ours with some slight differences. The majority of studies achieve a FP rate below 3%. Most FP cytological diagnoses turn out to be non-neoplastic lesions (nodular hyperplasia, adenomatous nodule, lymphocytic thyroiditis), which combined account for 80.5% of all histological diagnoses.

CONCLUSIONS

Thyroid nodules with FP cytology were larger than nodules with TP cytology. Most studies manage to adhere to the recommended FP rates, or values close to them, with some outliers. Nevertheless, the mean FP rate values are very close to the value recommended by The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). The FP rate value depends on how one defines true negative cases, which can be either histologically proven benign cases, via a benign clinical course, or by assuming that cytologically benign cases remain as such.

Diagnostic utility of fine needle aspiration cytology in pediatric thyroid nodules based on Bethesda Classification

OBJECTIVES

The Bethesda system for reporting cytopathology (TBSRTC) has been widely adopted in the management of thyroid nodules. Based on the limited pediatric data available, the implied malignancy risk for each of the categories may be significantly different in pediatrics vs. adults, especially in the indeterminate categories (Bethesda Class III or IV). We report the diagnostic utility of fine needle aspiration (FNA) biopsy at our institution based on the Bethesda system and the risk of malignancy in each category.

METHODS

We retrospectively reviewed all patients who underwent a thyroid FNA at our tertiary pediatric hospital from 12/1/2002 to 11/30/2018. FNA results were classified according to TBSRTC. Patient demographics, cytology, histopathology, radiological and clinical follow-ups were examined.

RESULTS

A total of 171 patients were included with 203 cytological samples. Average age at initial FNA was 14.7 years (range 6.9-18.6 years). The numbers of nodules reported for Bethesda categories I-VI were 29, 106, 22, 14, 6 and 26, respectively, and the rate of malignancy was: 13.8, 4.7, 22.7, 35.7, 83.3 and 100%, respectively. Use of ultrasound guidance reduced the non-diagnostic rate from 38.1 to 11.5%. Introduction of on-site adequacy testing further reduced the non-diagnostic rate to 6.5% since 2014.

CONCLUSIONS

The risk of malignancy for thyroid nodules in this pediatric cohort is higher than reported in adults. However, rates described here are much closer to adult ranges than previously published pediatric cohorts. The addition of adequacy testing improved the non-diagnostic rate of FNA procedures performed with ultrasound guidance.

Diagnostic Challenges of Medullary Thyroid Carcinoma

BACKGROUND

Medullary thyroid carcinoma (MTC) comprises 1-2% of all thyroid cancers, yet 15% of all thyroid cancer-related deaths. While up to 20% of cases may be predicted due to autosomal dominant germline mutations, 80% of cases are sporadic. However, due to non-specific presenting symptoms and diagnostic imaging, prompt diagnosis and treatment has remained elusive. This article will further investigate the limitations of MTC diagnosis and look into future areas for diagnostic improvement.

METHODS

Relevant articles were identified using a systematic PubMed and Google Scholar search.

RESULTS

Prophylactic total thyroidectomy for the 20% of MTC cases that are present in autosomal dominant disorder provides definitive treatment. Serum calcitonin (Ctn) screening has several technical limitations due to population variability and laboratory assay interference, but advances in laboratory technology and combined use with fine needle aspiration increase its sensitivity. Other serum assays such as carcinoembryonic antigen and procalcitonin have limited applicability. Thyroid ultrasound remains the gold standard for the initial diagnostic planning, with limited application for CT, MRI, and PET imaging.

CONCLUSION

With complete surgical resection the only definitive treatment, early MTC diagnosis has presented an elusive challenge, mainly due to its relative rarity and difficulty in finding an economic screening strategy. Careful family history combined with fine needle aspiration with serum Ctn analysis can improve diagnostic sensitivity and specificity to greater than 95%.

Outcomes of Indeterminate Thyroid Nodules Managed Nonoperatively after Molecular Testing

CONTEXT

Molecular testing to refine the diagnosis of cytologically indeterminate thyroid nodules has become increasingly popular, but data on long-term durability of test results and the rate of delayed operation are limited.

OBJECTIVE

Determine the delayed rate of surgical resection in indeterminate nodules with benign/negative molecular testing and the risk of false-negative molecular test results.

DESIGN

Prospective follow-up of the Gene Expression Classifier vs Targeted Next-Generation Sequencing in the Management of Indeterminate Thyroid Nodules randomized controlled trial comparing the diagnostic test performance of Afirma Gene Expression Classifier and ThyroSeq v2.

SETTING

University of California, Los Angeles.

PARTICIPANTS

Patients who underwent thyroid biopsy with indeterminate (Bethesda III/IV) cytology (April 2016 to July 2017).

INTERVENTION

Ultrasound surveillance.

MAIN OUTCOME MEASURE

False-negative rate of molecular testing.

RESULTS

Of 95 indeterminate nodules with negative/benign molecular test results, 12 nodules underwent immediate resection (11 benign nodules, 1 noninvasive follicular thyroid neoplasm nodule with papillary-like nuclear features). Nonoperative management was pursued for 83 (87.4%) nodules. The median surveillance was 26.7 months. Ten nodules were resected during surveillance and malignancy was identified in 4 nodules (overall false-negative rate of 5.8%). In the 4 malignant nodules that underwent delayed operation, surgery was prompted by sonographic changes during surveillance.

CONCLUSIONS

The majority of indeterminate nodules with negative molecular testing have a stable clinical course over 3 years of follow-up, but our finding of a 6% false-negative rate highlights the importance of continuing sonographic surveillance. Long-term studies are needed to determine the optimal length of follow-up.

The comparison of the histopathological results of the thyroid fine-needle aspiration biopsies in the 795 patients with thyroidectomy

BACKGROUND

We aimed to evaluate the effectiveness of preoperative fine-needle aspiration biopsies (FNAB) by the postthyroidectomy pathology results.

METHOD

Seven hundred and ninety-five patients with FNAB and following thyroid operations which have been performed between April 2008 and December 2019 were included in this study. By comparing the results of the FNAB and final pathologies, the specificity, sensitivity, FNR, false positivity ratio (FPR), accuracy and also the effect of nodule diameter on these have been evaluated. In Bethesda III subgroup according to FNAB, we investigated the malignancy rates and in whom this risk has been increased more.

RESULTS

In our study, the sensitivity of FNAB is 73.40%, the specificity is 95.33%, the accuracy is 91.81%, FNR is 26.60% and FPR is 4.67%. In the patients with nodules ≥4 cm and < 4 cm respectively, we calculated the sensitivity 20.0% vs 79.76%, specificity 95.73% vs 95.19%, accuracy 89.82% vs 92.78%, FNR 80.0% vs 20.24%, FPR 4.27% vs 4.8%.

CONCLUSION

Thyroid FNAB is an easy procedure with a high specificity and sensitivity. Nevertheless, when the nodule diameter was ≥4 cm, increased FNR and decreased sensitivity should be kept in mind while evaluating the patients.

Cytopathologic criteria and size should be considered in comparison of fine-needle aspiration vs. core-needle biopsy for thyroid nodules: results based on large surgical series

PURPOSE

To evaluate and compared the diagnostic performances of FNA and CNB using various cytopathologic criteria and size subgroups to see how the comparison results differ accordingly.

METHODS

From May 2012 to May 2019, 8187 thyroid nodules in 8139 patients who had undergone preoperative US-guided FNA or CNB at outside clinics were included in this retrospective study (mean size: 11.9 ± 9.5 mm). Preoperative US-FNA was performed in 7496 (91.6%) nodules and US-CNB was performed in 691 (8.4%) nodules. Propensity score matching was used to compare the sensitivities between FNA and CNB in diagnosis of malignancy and neoplasm according to different cytologic test criteria.

RESULTS

Of the 8187 thyroid nodules, 7833 (95.7%) were malignant and 354 (4.3%) were benign. Mean size of the thyroid nodules in the CNB group was significantly larger than the FNA group, 15.7 ± 12.7 mm vs. 11.6 ± 9.0 mm, respectively (P < 0.001). After matching, sensitivity in the CNB group were significantly higher in the total population, and in subgroups <10 mm for criteria 1 and 2 (all P < 0.05, respectively). No significant differences were seen between the sensitivities of FNA and CNB for nodules ≥10 mm regardless of criteria in diagnosis of malignancy or neoplasm (all P > 0.05, respectively).

CONCLUSIONS

Results comparing sensitivities between FNA and CNB differ according to the different cytopathologic criteria used for calculation. CNB has significantly higher sensitivity to FNA in subcentimeter nodules when using criteria 1 or 2. Diagnostic sensitivities did not show significant differences for nodules ≥10 mm regardless of the cytopathologic criteria used, that should be considered in selecting biopsy methods.

Adrenal metastasis as the initial diagnosis of synchronous papillary and follicular thyroid cancer

Background

Differentiated thyroid cancer uncommonly presents with distant metastases. Adrenal metastasis from differentiated thyroid cancer presenting as the initial finding is even less common.

Case Presentation

A 71-year-old male was incidentally found on chest CT to have bilateral thyroid nodules, which were confirmed on ultrasound. Fine needle aspiration of the dominant right 3.3 cm nodule contained histologic features most consistent with Bethesda classification III, and repeat fine needle aspiration revealed pathology consistent with Bethesda classification II. Follow-up thyroid ultrasound showed 1% increase and 14% increase in nodule volume at one and two years, respectively, compared to baseline. Prior to the second annual thyroid ultrasound, the patient was incidentally found to have a 4.1 cm heterogeneously enhancing mass in the right adrenal gland on CT of the abdomen and pelvis. Biochemical evaluation was unremarkable with the exception of morning cortisol of 3.2 µg/dL after dexamethasone suppression. The patient then underwent laparoscopic right adrenal gland excision, which revealed metastatic follicular thyroid carcinoma. Total thyroidectomy was then performed, with pathology showing a 4.8 cm well-differentiated follicular thyroid carcinoma of the right lobe, a 0.5 cm noninvasive follicular thyroid neoplasm with papillary-like nuclear features of the left lobe, and a 0.1 cm papillary microcarcinoma of the left lobe. Thyrotropin-stimulated whole body scan showed normal physiologic uptake of the remnant thyroid tissue without evidence of other iodine avid disease. The patient then received radioactive iodine. At follow-up 14 months after total thyroidectomy, he remains free of recurrent disease.

Conclusion

Despite following the recommended protocol for evaluation and surveillance of thyroid nodules, thyroid cancer can be challenging to diagnose, and may not be diagnosed until distant metastases are identified.

The Risk of Thyroid Cancer in Patients with Thyroid Nodule 3 Cm Or Larger

OBJECTIVE

There are conflicting data on the risk of thyroid cancer in thyroid nodules 3 cm or larger, and few such studies on this issue have been conducted in Asia. This study aimed to examine the risk of thyroid cancer in patients with thyroid nodules 3 cm or larger.

METHODS

This was a 7-year retrospective study conducted in a tertiary referral hospital in Taiwan. All patients with a thyroid nodule measuring ≥3 cm who underwent thyroid operation with or without fine-needle aspiration biopsy (FNAB) were included. The prevalence rate of thyroid cancer, as well as the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and false-negative rate of FNAB for thyroid nodule ≥3 cm were also examined.

RESULTS

A total of 132 patients were included in this study. Thyroid cancer was detected in 19 of 132 (14.4%) thyroid nodules measuring ≥3 cm. The performance of FNAB for detecting cancer in nodules 3 cm or larger without considering other ultrasonography parameters was relatively poor with a sensitivity of 50%, but the specificity (100%), PPV (100 %), and NPV (93.4 %) were excellent.

CONCLUSION

The risk of thyroid cancer for thyroid nodules ≥3 cm in this study was low. The PPV and NPV of FNAB were high for the detection of cancer in large nodules. The decision to perform thyroidectomy should not be solely based on nodule size and should include other factors, such as ultrasound characteristics and surgical risk.

The relationship of thyroid nodule size on malignancy risk according to histological type of thyroid cancer

Background

Although several studies have examined the value of thyroid nodule size as a malignancy predictor, the results are conflicting.

Purpose

To investigate the relationship between nodule size and malignancy risk and to evaluate the impact of nodule size on the false-negative rate of fine needle aspiration or core needle biopsy according to the histological type of thyroid cancer.

Material and Methods

From January 2013 to December 2013, 3970 thyroid nodules that underwent ultrasound-guided fine needle aspiration or core needle biopsy were retrospectively reviewed. We assessed the relationship between nodule size and malignancy risk according to histological type of thyroid cancer. In addition, we compared the false-negative rate by thyroid nodule size category.

Results

Of 3970 thyroid nodules, 1170 nodules were malignant. For papillary thyroid carcinoma, nodule size was inversely related to malignancy risk, whereas in nodules of follicular carcinoma and follicular variant papillary thyroid carcinoma, nodule size was positively related to malignancy risk ( P < 0.001). The false-negative rate tended to increase as nodule size increased ( P = 0.002) for all nodules and the overall false-negative rate was 2.3%.

Conclusion

Overall, nodule size does not correlate with risk of malignancy, but the relationship between nodule size and malignancy risk depends on the histological type of thyroid cancer.

Causes of misdiagnoses by thyroid fine-needle aspiration cytology (FNAC): our experience and a systematic review

Objective

FNA is a simple, safe, cost-effective and accurate diagnostic tool for the initial screening of patients with thyroid nodules. The aims of this study were to determine the diagnostic utility of FNAC performed in our institution, assess the cytomorphologic features that contribute to diagnostic errors and propose improvement measures.

Methods

A total of 2781 FNACs were included in the study, and 1122 cases were compared with their histological diagnoses. We retrospectively reexamined our discordant (both false-negative and false-positive) cases and performed a systematic review of previous studies on causes of misdiagnoses.

Results

When DC V and DC VI were both considered cytologic-positive, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy were 98.3, 30.9, 94.9, 58.3 and 93.5%, respectively. If DC VI was considered cytologic-positive, the sensitivity, specificity, PPV, NPV and diagnostic accuracy of FNAC were 98.0, 84.0, 99.4, 58.3, and 97.5% respectively. The main cause of false-negative diagnoses was sampling error (13/15, 86.7%), while interpretation error led to the majority of the false-positive diagnoses (38/47, 80.9%). Overlapping cytological features in adenomatous hyperplasia, thyroiditis and cystic lesions were the major factors contributing to interpretation errors, while the size and number of nodules may have led to false-negative diagnoses because of heterogeneity and unsampled areas.

Conclusions

The sensitivity and PPV of thyroid FNAC in our institution were higher than those in the published data, while the specificity and NPV were lower. Regarding the FNA category DC V, a frozen section analysis during diagnostic lobectomy is necessary. Multiple passes should be performed in various parts of a large nodule or from different nodules to reduce the risk of false-negative findings. Cytopathologists should strengthen their criteria for the identification of adenomatous hyperplasia, thyroiditis and cystic lesions to avoid false-positive diagnoses. NIFTP has little effect on diagnostic accuracy and the distribution of diagnostic errors.

Association between thyroid nodule size and malignancy rate

INTRODUCTION

The diagnostic performance of ultrasound-fine needle aspiration to identify thyroid nodules harbouring malignancy remains variable. The aim of this study was to determine thyroid nodule size and cytological classification as predictors of malignancy risk.

MATERIALS AND METHODS

We conducted a retrospective cohort analysis at an academic hospital involving 499 consecutive patients who underwent thyroid surgery between 2004 and 2015.

RESULTS

A total of 503 thyroid nodules (499 patients, 84% female; mean age 50.8 years, standard deviation, SD, 15.4 years) were analysed. Of these, 19.5% were malignant. The mean (± SD) nodule size was 3.28 ± 1.63 cm and 3.27 ± 1.54 cm for benign and malignant nodules, respectively. The odds of malignancy for thyroid nodules less than 3.0 cm was similar to those for nodules of 3.0 cm or greater (0.26 compared with 0.29; p=0.77). Overall, the sensitivity and specificity of fine-needle aspiration in this cohort were 71.4% and 100%, respectively. The overall false negative rate was 5.4%. When the cut-off of 3.0 cm was used, the false negative rate in thyroid nodules less than 3.0 cm was 0% compared with 7.0% in nodules of 3.0 cm or greater. Thus, class (p<0.01) but not nodule size (p=0.49), was associated with higher malignancy risk.

CONCLUSIONS

Our results suggest that thyroid nodule size did not accurately predict the risk of thyroid malignancy irrespective of fine-needle aspiration cytology. Routine diagnostic thyroid lobectomy solely owing to thyroid nodule size of 3.0 cm or greater is currently not justified.

Impact of molecular testing on thyroid nodule neoplastic diagnosis, stratified by 4-cm size, in a surgical series

Whether molecular testing adds diagnostic value to the evaluation of thyroid nodules 4-cm or larger is unknown. The impact of molecular testing on cytopathologic-histopathologic diagnosis of neoplasm (adenoma or malignant), stratified by nodule size Collapse

Key Words

• thyroid diseases
• thyroid cancer

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MESH Headings

• Adenoma/genetics
• Adenoma/pathology
• Biomarkers, Tumor/genetics
• Biomarkers, Tumor/standards
• Biopsy, Fine-Needle/statistics & numerical data
• Genetic Testing/standards
• Genetic Testing/statistics & numerical data
• Humans
• Mutation
• Thyroid Nodule/genetics
• Thyroid Nodule/pathology

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Grants

• UL1TR002494 U.S. Department of Health & Human Services | NIH | National Center for Advancing Translational Sciences (NCATS)
• The Scientific and Technical Research Council of turkey (TUBITAK)

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Affiliation(s)

Rupendra T Shrestha Department of Medicine, University of Minnesota, Minneapolis, USA
Muhammed Kizilgul Department of Medicine, University of Minnesota, Minneapolis, USA Department of Endocrinology and Metabolism, UHS Diskapi Training and Research Hospital, Ankara, Turkey
Maryam Shahi Department of Pathology, University of Minnesota, Minneapolis, USA
Khalid Amin Department of Pathology, University of Minnesota, Minneapolis, USA
Maria R Evasovich Department of Surgery, University of Minnesota, Minneapolis, USA
Lynn A Burmeister Department of Medicine, University of Minnesota, Minneapolis, USA.

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Thyroid nodules over 4 cm do not have higher malignancy or benign cytology false-negative rates

PURPOSE

Whether thyroid nodules 4 cm or larger with benign cytology carry a higher risk of malignancy, and should be managed differently than smaller nodules remains controversial. We aimed to evaluate the malignancy rate and benign cytology false-negative rate in thyroid nodules ≥4 cm compared with those <4 cm.

METHODS

All thyroidectomies between January 2010 and December 2014 were reviewed. Patient demographics, preoperative sonographic nodule size, fine needle aspiration cytology (FNAC), and final surgical pathology results were compared for index nodules ≥4 vs. <4 cm.

RESULTS

A total of 490 index nodules with preoperative FNAC were identified. A total of 137 nodules were ≥4 cm and 353 nodules were <4 cm. The prevalence of carcinoma was lower (23 vs. 53%) in nodules ≥4 vs. <4 cm (p < 0.0001). The false-negative rate of benign FNAC for ≥4 and <4 cm index nodule was 5.2% and 5.9%, respectively (p = 1.000).

CONCLUSIONS

This study shows that thyroid nodules ≥4 cm do not have a higher malignancy rate at surgery nor higher benign cytology false-negative rate than smaller nodules. Thyroid nodules over 4 cm do not require resection, to rule out malignancy, based on size alone.

Treatment of solitary thyroid nodules according to size, preoperative fine-needle aspiration cytology and frozen section: a retrospective single centre study

Background: In order to avoid unnecessary thyroidectomies, it is important to predict the nature of thyroid nodules the more accurately possible. The size of the nodule as a predictive factor for malignancy is very controversial. Another point of debate is the accuracy of preoperative fine-needle aspiration cytology (FNAC) and frozen section (FS). The aim of our study is to correlate the nodule size with the final histological diagnosis and to estimate the accuracy of preoperative FNAC and FS. Methods: Retrospective study including 387 operated patients with ultrasound-detected solitary thyroid nodules from 01 January 2001 to 31 December 2013. The following data were collected: patient age and sex, nodule size, FNAC, FS and final histology results. Results: The odds ratio for malignancy within nodules <40 mm was 2.12 (95% CI: 1.104-4.084). The specificity of FNAC was 97.78% and the negative predictive value (NPV) was 97.78% for nodules ≥40 mm and 93.2% and 96.5% for nodules <40 mm, respectively. The observed specificity and NPV of FS ranged from 98% to 100% and from 87.4% to 98%, respectively. When combining FNAC and FS, the specificity and the NPV were 99% and 98%, respectively. Conclusions: The nodule size is not a predictive factor for thyroid cancer and therefore nodules ≥40 mm should not be routinely resected. A lege artis preparation and performance of FNAC along with an expertise on cytological interpretation can considerably diminish false-negative rate. FS can offer additional accuracy on FNAC results and should, therefore, be a part of patient treatment.

Risk of Thyroid Cancer in 1,504 Patients Referred for Thyroid Surgery with Assumed Benign Histology

OBJECTIVES

The aims of this study were to report the risk of thyroid malignancy in cases of either benign fine-needle aspiration (FNA) or without FNA performed, and to investigate possible predictive factors for thyroid malignancy in a population with recent moderately low iodine intake.

METHODS

All patients referred for thyroid surgery in a tertiary cancer centre between 2000 and 2016 were included (n = 3,703). After excluding cases indicating malignant histology, we included group 1: patients with benign FNA (n = 764), and group 2: patients without FNA (n = 740), leaving 1,504 eligible for further investigation. Information on age, gender, tracheal compression or dislocation, thyroid specimen weight, scintigraphy, ultrasound, medically treated thyrotoxicosis, serum stimulating thyroid hormone, indication for surgery, TNM classification, stage, and outcome were retrieved.

RESULTS

The malignancy risk was 7.6% (58/764) in group 1 and 6.8% (50/740) in group 2. Patients with T2-4 tumours constituted 2.2% (33/1,504). In the combined groups, ultrasound verified that solitary solid tumour was predictive for malignancy (p = 0.01 by χ², and OR = 1.69, p = 0.02 in multiple logistic regression). For group 1 patients, thyrotoxicosis (which in this case was medically treated) was a significant predictive factor for malignancy (p = 0.04).

CONCLUSIONS

The risk of malignancy of 7.6% and 6.8% was high, considering that patients with malignant FNA, suspicious FNA, or clinical findings indicating malignancy were excluded, and 2.2% of these malignancies were stages T2-4. In cases with solitary solid tumour on ultrasound, the risk of malignancy should not be ignored, even with benign FNA.

Use of Shear Wave Elastography in the Sonographic Triage of Thyroid Nodules: Feasibility Study in a Series of Lesions Already Selected for Fine Needle Aspiration

OBJECTIVES

The aim of this study was to evaluate the application of shear wave elastography (SWE) in the routine management of thyroid nodules, as a possible additional tool to the standard sonographic triage.

METHODS

A total of 248 consecutive patients scheduled for ultrasound-guided thyroid fine-needle aspiration were included in the study. The presence of a pure colloid lesion was an exclusion criterion. Absolute and relative SWE stiffness measurements on color-coded elastograms, expressed in kilopascals and meters per second, were correlated with radiologic and pathologic features.

RESULTS

SWE values in thyroid nodules were significantly higher than normal thyroid tissue (P = .0001), proving the different elastic properties of the pathologic tissues. Regarding the radiologic characteristics of the nodules, SWE highest values were associated with the largest lesions (P = .0105) but independent from sonographic and Doppler findings. The SWE elasticity was not influenced by the characteristics of the biopsy smears. The final correlation between the SWE results and the pathologic diagnoses showed a trend in stiffness from tender tumors (follicular adenoma) to papillary thyroid carcinoma (P = .016).

CONCLUSIONS

SWE allows the identification of nodules within normal parenchyma; however, the present study does not confirm the potential role in differentiating between benign and malignant thyroid nodules.

The influence of thyroid nodule size on the diagnostic efficacy and accuracy of ultrasound guided fine-needle aspiration cytology

BACKGROUND

Diagnostic accuracy of fine-needle aspiration cytology (FNAC) in large and subcentimeter nodules is still debated. We aimed to evaluate the impact of nodule size on efficacy of the ultrasound-guided FNAC.

METHODS

B-mode grayscale ultrasound (US), US-guided FNAC according to Bethesda system and histopathological data of 514 nodules from 371 patients, who underwent thyroidectomy were examined retrospectively. Nodules were grouped by maximal diameter; group A nodules were smaller than 10 mm (n = 59), group B nodules were between 10 and 29 mm (n = 218), and group C nodules were 30 mm or greater (n = 130).

RESULTS

Sensitivity, specificity, and accuracy of FNAC was 92.0%, 100%, and 95.1% in group A, 80.7%, 99.1%, and %92.9 in group B, 70.0%, 98.9%, and 95.8% in group C nodules, respectively. The prevalence of papillary thyroid cancer (PTC) and incidental PTC were 44.2% (n = 164) and 6.4% (n = 24), respectively. Malignancy rate was more frequent in group A when compared to groups B and C (P < 0.01). Nodule size was positively associated with follicular cancer risk (P = 0.009). The thyroid stimulating hormone level was positively associated with malignancy (P = 0.02) and optimal cut-off value was 0.96 mIU/L. False-negative rate was 8.0%, 19.3%, and 30.0% in groups A, B, and C nodules, respectively.

CONCLUSIONS

Although the malignancy rate was low in nodules ≥30 mm, diagnostic surgery for large nodules should be considered because of decreased reliability of FNAC, ineffectiveness of clinical and sonographic criteria. False-negative rate was relatively low and malignancy rate was high in subcentimeter nodules, supporting the accuracy of FNAC.

Malignancy risk for thyroid nodules larger than 4 cm and diagnostic reliability of ultrasound-guided FNAB results

Objectives

Our aim in the present study was to investigate the relation between thyroid nodule diameter and malignancy, and the diagnostic accuracy of fine needle aspiration biopsy (FNAB) for thyroid nodules larger than 4 cm.

Material and Methods

Preoperative patient demographics such as age and gender, thyroid nodule diameter, FNAB results and postoperative pathology results were recorded. The relation between age, gender, thyroid nodule size of the patients and malignancy was examined. Also, the sensitivity, specificity, false negativity, false positivity and accuracy rates of FNBA of the patients whose thyroid nodule size was lower than 4 cm and the ones whose thyroid nodule size was higher than 4 cm were analyzed.

Results

There was no significant difference between males and females in terms of malignancy rate (p= 0.15). There was no significant relation between malignancy and patient age (p= 0.92). No significant difference was found between the group with thyroid nodule diameter of > 4 cm and the group thyroid with nodule diameter of <4 cm in terms of malignancy (p= 0.91). In the group with thyroid nodule diameter of > 4 cm, sensitivity, specificity, false negativity, false positivity, and accuracy rates of FNAB were 15%, 100%, 84%, 0%, and 70%, respectively. In the group with thyroid nodule diameter of <4 cm, sensitivity, specificity, false negativity, false positivity, and accuracy rates of FNAB were 53%, 100%, 46%, 0% and 80%, respectively.

Conclusion

Our study put forward that thyroid nodule diameter is not the only predictor parameter whilst predicting malignancy. However, it was observed that FNAB sensitivity and false negativity were higher when the thyroid nodules with > 4 cm diameter were compared to the thyroid nodules with <4 cm diameter.

Differentiation between benign and malignant thyroid nodules using diffusion-weighted imaging, a 3-T MRI study

Background:

Preoperative differentiation of benign from malignant thyroid nodules remains a challenge. Aims: This study assessed the accuracy of diffusion-weighted imaging (DWI) for differentiation between benign and malignant thyroid nodules.

Materials and Methods:

Preoperative DWI was performed in patients with thyroid nodule by means of a 3-T scanner magnetic resonance imaging (MRI). Images were obtained at b value of 50, 500, and 1000 mm²/s to draw an ADC (apparent diffusion coefficient) map. Findings were compared with postoperative histopathologic results. Receiver operating characteristic curve was used to assess the accuracy of different cutoff points.

Results:

Forty-one thyroid nodules (26 benign and 15 malignant) were included in this study. None of static MRI parameters such as signal intensity, heterogeneity, and nodule border was useful to discriminate between benign and malignant lesions. Mean ADC value was (1.94 ± 0.54) × 10^-3 mm²/s and (0.89 ± 0.29) × 10^-3 mm²/s in benign and malignant nodules, respectively (P-value < 0.005). ADC value cutoff of 1 × 10^-3 mm²/s yielded an accuracy, sensitivity, and specificity of 93%, 87%, and 96% to discriminate benign and malignant nodules.

Conclusion:

DWI is highly accurate for discrimination between benign and malignant thyroid nodules.

Is Frozen-Section Analysis During Thyroid Operation Useful in the Era of Molecular Testing?

BACKGROUND

With the increased use of molecular testing of thyroid fine-needle biopsies, the frequency and extent of thyroid resection for thyroid nodules has changed. Although the role of frozen-section analysis of the thyroid has been reduced markedly in recent years, many surgeons still routinely use it intraoperatively. We sought to determine the utility of frozen section during thyroidectomy in the era of molecular testing.

STUDY DESIGN

We reviewed 236 consecutive patients who had thyroidectomy with intraoperative frozen-section analysis at our institution between November 2015 and October 2017. We re-reviewed the preoperative diagnosis, frozen-section diagnosis, final pathology, and whether operative management changed from the initial plan based on frozen section.

RESULTS

Mean age of the patients was 55.6 ± 14.1 years, and 83% were female. Of the 236 patients, frozen section did not change the intraoperative management in 225 (95%). Of the 11 patients whose thyroid operation was modified, the operation was either too much or not enough in 6 patients. In only 5 (2.1%) patients, frozen-section analysis correctly changed the extent of thyroidectomy.

CONCLUSIONS

Thyroid frozen-section analysis adds cost and time to thyroid operations without notable benefit. In our cohort, only 2.1% of frozen sections accurately changed intraoperative management. We recommend against its routine use.

The diagnostic accuracy of contrast-enhanced ultrasound for the differentiation of benign and malignant thyroid nodules: A PRISMA compliant meta-analysis

BACKGROUND

Contrast-enhanced ultrasound (CEUS) is a non-invasive method that has been used in the diagnosis of several diseases. Recently, CEUS has been used in the differentiation of benign and malignant thyroid nodules. However, the performance of CEUS in thyroid nodules has not been studied clearly.

METHODS

The databases of Pubmed, Embase, Cochrane library and the unpublished studies were systematically searched for candidate inclusions, with the use of CEUS in differentiating the benign and malignant thyroid nodules. The quality of included studies was assessed using Quality Assessment of Diagnostic Accuracy Studies (QUADAS) questionnaire. The pooled estimates of sensitivity, specificity, diagnostic odds ratio (DOR), positive and negative likelihood ratio (NLR) were calculated using STATA software version 14.0.

RESULTS

Totally 33 diagnostic studies were included for further analysis. The quality of included studies was relatively high using QUADAS method. The pooled estimates of sensitivity and specificity were 0.88 (95% CI 0.85, 0.91) and 0.88 (95% CI 0.83, 0.91), respectively. In addition, the DOR, the positive and NLRs were pooled positive LR and the negative LR were 54 (95% CI 33, 89), 7.1% (5.2%, 9.8%), and 0.13% (0.10%, 0.18%). No significant publication bias was observed.

CONCLUSIONS

Our meta-analysis further indicated that CEUS is a useful tool in differentiating benign and malignant thyroid nodules, with high sensitivity and specificity.

Large Cytologically Benign Thyroid Nodules Do Not Have High Rates of Malignancy or False-Negative Rates and Clinical Observation Should be Considered: A Meta-Analysis

Background: Management of large thyroid nodules is controversial, as data are conflicting regarding overall rates of malignancy (ROM) in all nodules and frequency of false-negative fine-needle aspiration results (FNR) in cytologically benign nodules. This meta-analysis aimed to evaluate and compare ROM and FNR in small versus large nodules published in the literature. Methods: Articles indexed in PubMed, written in English, published electronically or in print on or prior to December 8 2017 were searched for "false negative thyroid size or cm" and "malignancy rates benign thyroid nodules." Three hundred fifty-two unique citations were identified. Multiple reviewers selected a final set of 35 articles that contained nodules stratified by size (3, 4, or 5 cm), with benign or all cytologic diagnoses, and with postsurgical histologic diagnoses. Multiple observers extracted data, including numbers of total, cytologically benign, and histologically malignant nodules. Size cutoffs of 3, 4, and/or 5 cm were analyzed in 14, 24, and 1 article, respectively. Results: ROM in all nodules ≥3 cm (13.1%) and ≥4 cm (20.9%) was lower than those <3 cm (19.6%) and <4 cm (19.9%; odds ratio [OR] = 0.72 [confidence interval (CI) 0.64-0.81] and OR = 0.85 [CI 0.77-0.95]). FNR in nodules ≥3 cm (7.2%) was not different from smaller nodules (5.7%; OR = 1.47 [CI 0.80-2.69]). FNR in nodules ≥4 cm (6.7%) was slightly higher than those <4 cm (4.5%; OR = 1.38 [CI 1.06-1.80]). The most frequently reported false-negative diagnosis was papillary thyroid carcinoma. Conclusions: Rates of malignancy and false-negative FNA results vary but, in most studies, are not higher in larger nodules. Patients with large, cytologically benign thyroid nodules need not undergo immediate surgical resection, as false-negative FNA rates are low and are expected to decrease in light of nomenclature revision of a subset of follicular variants of papillary thyroid carcinoma.

Utility of Intraoperative Frozen Section in Large Thyroid Nodules

OBJECTIVE

To determine if the routine use of intraoperative frozen section (iFS) results in cost savings among patients with nodules >4 cm with nonmalignant cytology undergoing a thyroid lobectomy.

STUDY DESIGN

Case series with chart review; cost minimization analysis.

SETTING

Single academic center.

SUBJECTS AND METHODS

Records were reviewed on a consecutive sample of 48 patients with thyroid nodules >4 cm and nonmalignant cytology who were undergoing thyroid lobectomy in which iFS was performed between 2010 and 2015. A decision tree model of thyroid lobectomy with iFS was created. Comparative parameters were obtained from the literature. A cost minimization analysis was performed comparing lobectomy with and without iFS and the need for completion thyroidectomy with costs estimated according to 2014 data from Medicare, the Bureau of Labor Statistics, and the Nationwide Inpatient Sample.

RESULTS

The overall malignancy rate was 25%, and 33% of these malignancies were identified intraoperatively. When the malignancy rates obtained from our cohort were applied, performing routine iFS was the less costly scenario, resulting in a savings of $486 per case. When the rate of malignancy identified on iFS was adjusted, obtaining iFS remained the less costly scenario as long as the rate of malignancies identified on iFS exceeded 12%. If patients with follicular lesions on cytology were excluded, 50% of malignancies were identified intraoperatively, resulting in a savings of $768 per case.

CONCLUSIONS

For patients with nodules >4 cm who are undergoing a diagnostic lobectomy, the routine use of iFS may result in decreased health care utilization. Additional cost savings could be obtained if iFS is avoided among patients with follicular lesions.

The Value of Negative Diagnosis in Thyroid Fine-Needle Aspiration: a Retrospective Study with Histologic Follow-Up

The Bethesda System for reporting thyroid cytopathology (BSRTC) predicts an incidence of malignancy of less than 5% in thyroid nodules with a benign diagnosis on fine-needle aspiration (FNA). However, recent series have suggested that the true rate of malignancy might be significantly higher in this category of patients. We reviewed our experience by performing a retrospective analysis of patients with benign thyroid FNA results who underwent thyroidectomy between 2008 and 2013 at a large academic center. Information including demographics, ultrasound features, FNA diagnosis, and surgical follow-up information were recorded. Slides were reviewed on cytology-histology discrepant cases, and it was determined whether the discrepancy was due to sampling or interpretation error. A total of 802 FNA cases with a benign diagnosis and surgical follow-up were identified. FNA diagnoses included 738 cases of benign goiter and 64 cases of lymphocytic thyroiditis. On subsequent surgical resection, 144 cases were found to be neoplastic, including 117 malignant cases. False negative, defined as interpretation error and inadequate biopsy of the nodule harboring malignancy, was 6%. When cases of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) were excluded from the analysis, false-negative rate was 5%. When microPTC cases were excluded, false-negative rate was 3% and was slightly less than 3% when both microPTC and NIFTP cases were excluded from the analysis. Retrospective review of neoplastic cases showed that 57% were due to sampling error and 43% were due to interpretation error. Interpretation error was more likely to occur in follicular patterned neoplasms (75%), while sampling error was more common in non-follicular variants of papillary thyroid carcinoma (non-FVPTC) (61%). With the exclusion of microPTC, interpretation errors were still more likely to occur in follicular neoplasms (79%) but there was no significant difference in sampling error between non-FVPTC (37%) and follicular patterned neoplasms (42%). Tumor size was larger in cases with interpretation error (mean = 2.3 cm) compared to cases with sampling error (mean = 1.4 cm). This study shows that the false-negative rate of thyroid FNA at our institution is not significantly above the rate suggested by the BSRTC. Interpretation errors were more likely to occur in follicular patterned neoplasms, while non-FVPTC was more frequently found in false negative cases due to inadequate sampling.

Prevalence of Cancer in Thyroid Nodules In the Veteran Population

A 16-year retrospective chart review found no relationship between nodule size and malignancy, emphasizing the need for individualized care.

The risk of thyroid carcinoma in multinodular goiter compared to solitary thyroid nodules: A retrospective analysis of 600 patients

Background

It is generally believed that multinodular goiter (MNG) is associated with a lower risk of malignancy compared to solitary thyroid nodules (STN). This will be the null hypothesis in this retrospective study and we aim to prove or reject it.

Methods

Medical files and histopathology reports of 600 patients who underwent thyroidectomy over 4-year period were reviewed. Data including patient' age, gender, presentation, ultrasonography, FNAC, surgical procedures, final histopathologic diagnosis and stage of malignant tumors were collected and analyzed. The primary end point was assessment of risk of thyroid carcinoma in patients with MNG compared to those with STN. Secondary endpoints included demographic differences and prognosis.

Results

There were 459 females (76.5%). Mean age was 44.3 ± 14.5 years (range 14-85). After exclusion of 33 patients, 224 (39.5%) had STN and 343 (60.5%) had MNG. The prevalence of thyroid cancer was 41.1% (92/224) in STN compared to 29.2% (100/343) in MNG (Chi-Square = 8.593, p < 0.01). However, on multiple logistic regression analysis this correlation was found insignificant (p = 0.640). Only male gender (p = <0.000005) and preoperative impression of malignancy (p = 0.000082) were significantly associated with thyroid carcinoma.

Conclusion

The risk of thyroid carcinoma in STN and MNG was similar. Male gender was identified as a risk factor for thyroid cancer while age, number and size of nodules were not.

Predictivity of clinical, laboratory and imaging findings in diagnostic definition of palpable thyroid nodules. A multicenter prospective study

PURPOSE

To assess the role of clinical, biochemical, and morphological parameters, as added to cytology, for improving pre-surgical diagnosis of palpable thyroid nodules.

METHODS

Patients with a palpable thyroid nodule were eligible if surgical intervention was indicated after a positive or suspicious for malignancy FNAC (TIR 4-5 according to the 2007 Italian SIAPEC-IAP classification), or two inconclusive FNAC at a ≥3 months interval, or a negative FNAC associated with one or more risk factor. Reference standard was histological malignancy diagnosis. Likelihood ratios of malignancy, sensitivity, specificity, negative (NPV), and positive predictive value (PPV) were described. Multiple correspondence analysis (MCA) and logistic regression were applied.

RESULTS

Cancer was found in 433/902 (48%) patients. Considering TIR4-5 only as positive cytology, specificity, and PPV were high (94 and 91%) but sensitivity and NPV were low (61 and 72%); conversely, including TIR3 among positive, sensitivity and NPV were higher (88 and 82%) while specificity and PPV decreased (52 and 63%). Ultrasonographic size ≥3 cm was independently associated with benignity among TIR2 cases (OR of malignancy 0.37, 95% CI 0.18-0.78). In TIR3 cases the hard consistency of small nodules was associated with malignity (OR: 3.51, 95% CI 1.84-6.70, p < 0.001), while size alone, irrespective of consistency, was not diagnostically informative. No other significant association was found in TIR2 and TIR3.

CONCLUSIONS

The combination of cytology with clinical and ultrasonographic parameters may improve diagnostic definition of palpable thyroid nodules. However, the need for innovative diagnostic tools is still high.

Investigation of thyroid nodules: A practical algorithm and review of guidelines

BACKGROUND

High resolution ultrasound has led to early detection of subclinical tumors and drastic increase in incidence of thyroid malignancy. To achieve a balance in appropriate investigation without perpetuating an overdiagnosis phenomenon, a concise set of evidence-based recommendations to stratify risk is required.

METHODS

We sought to assemble an evidence-based diagnostic algorithm and accompanying pictorial review for workup of thyroid nodules that summarizes the most recent guidelines. In addition, we conducted a literature search and analysis of our imaging databases.

RESULTS

Although many imaging features of benign and malignant nodules can be nonspecific, others, such as microcalcifications, lymphadenopathy, and peripheral invasion, are highly suggestive of malignancy. The predictive values of salient imaging characteristics are presented.

CONCLUSION

Evidence-based guidelines are available such that a cost-effective algorithm for thyroid nodule workup can be devised. Conservative management with a focus on periodic monitoring is the working clinical consensus on the approach to thyroid nodules.

Validation of the 2015 American Thyroid Association Management Guidelines for Thyroid Nodules With Benign Cytologic Findings in the Era of the Bethesda System

OBJECTIVE

The purpose of this study is to investigate follow-up strategies for cytologically benign thyroid nodules according to size and ultrasound (US) pattern according to the 2015 American Thyroid Association (ATA) guidelines in the era of the Bethesda system.

MATERIALS AND METHODS

This retrospective study included 1208 patients with 1230 nodules that were cytologically benign at initial fine-needle aspiration performed from June 2012 to December 2014. False-negative rates (FNRs) were calculated by considering nodule size and US pattern according to the 2015 ATA guidelines and were compared between nodules with the high-suspicion US pattern and nodules with the high- or intermediate-suspicion US patterns according to size.

RESULTS

Twenty-five of the 1230 nodules (2.0%) were malignant. The FNRs were 5.1% (8/158) for nodules with the high-suspicion US pattern and 1.6% (17/1072) for nodules with other US patterns. With regard to nodule size, the FNRs were 3.2% (9/277) for nodules 3 cm or larger and 5.2% (6/115) for nodules 4 cm or larger. The FNRs of nodules with the high-suspicion pattern were not significantly higher than those of nodules with the high- or intermediate-suspicion patterns among nodules 2 cm or larger (2.5% vs 1.9%; p = 0.208), 3 cm or larger (3.4% vs 2.9%; p = 0.498), and 4 cm or larger (5.4% vs 3.8%; p = 0.353).

CONCLUSION

Thyroid nodules with initial benign cytologic findings had a low malignancy rate in the era of the Bethesda system, regardless of US pattern and size. Therefore, any immediate diagnostic intervention may be discouraged in cytologically benign nodules.

Predictors of a follicular nodule (Thy3) outcome of thyroid fine needle aspiration cytology among Saudi patients

Objective

A retrospective study was performed to evaluate predictors of thyroid fine needle aspiration cytology (FNAC) outcomes among Saudis with a thyroid nodule. Socio-demographic data, thyroid function status, thyroid parameters, ultrasound and cytology results were collected from 269 files of patients with thyroid nodules.

Result

The patients’ age was 40 ± 1.4 years (mean ± SD), and the mean body mass index (BMI) was 30.3 ± 1.2 kg/m². The thyroid statuses were euthyroid (85.5%), hypothyroidism (7.4%) and hyperthyroidism (7.1%). Young age, an absence of irradiation history, and multinodular goitre were protective against Thy3 [(OR = 0.05, CI = 003–0.6, P = 0.024), (OR = 0.4, CI = 0.2–0.8, P = 0.012) and (OR = 2.5, CI = 1.2–5.3, P = 0.016), respectively]; a lower FT3 was protective against Thy4 (OR = 0.4, CI = 0.2–0.99, P = 0.046), the absence of cervical lymphadenopathy was associated with Thy2 (OR = 2.7, CI = 1.4–5, P = 0.001), and a solid nodule was associated with Thy2 and Thy3 [(OR = 1.2, CI = 0.3–0.97, P = 0.040) and (OR = 2.2, CI = 1–4.8, P = 0.039), respectively]. In a multivariate analysis, younger age, multinodular goitre, an absence of irradiation history and cervical lymphadenopathy were protective against Thy3 [(OR = 0.04, 95% CI = 0.002–0.96, P = 0.047), (OR = 2.4, 95% CI = 1.0–5.60, P = 0.039), (OR = 0.4, 95% CI = 0.16–0.94, P = 0.036) and (O R = 0.39, 95% CI = 1–5.6, P = 0.039), respectively]. In summary, younger age, multinodular goitre, the absence of an irradiation history and cervical lymphadenopathy were protective against Thy3 in a thyroid nodule.

Large (≥3cm) thyroid nodules with benign cytology: Can Thyroid Imaging Reporting and Data System (TIRADS) help predict false-negative cytology?

Background

There is controversy about the accuracy of the fine-needle aspiration (FNA) cytology results in large sized thyroid nodules. Our aim was to evaluate the false-negative rate of FNA for large thyroid nodules and the usefulness of the Thyroid Imaging Reporting and Data System (TIRADS) in predicting false-negative cytology for large thyroid nodules with benign cytology.

Methods

632 thyroid nodules larger than or equal to 3cm in size with subsequent benign cytology on US-guided FNA were included. US features of internal composition, echogenicity, margin, calcifications, and shape were evaluated, and nodules were classified according to TIRADS. TIRADS category 3 included nodules without any of the following suspicious features:solidity, hypoechogenicity or marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, and taller-than-wide shape. Category 4a, 4b, 4c, and 5 were assigned to nodules showing one, two, three or four, or five suspicious US features, respectively. US features associated with malignancy for these lesions were analyzed and malignancy risk according to TIRADS was calculated.

Results

Of the 632 lesions, 23 lesions(3.6%) were malignant and 609(96.4%) were benign, suggesting a 3.6% false-negative rate for FNA cytology. Of the 23 malignant lesions, final pathology was mainly follicular carcinoma minimally invasive(65.2%, 15/23) and the follicular variant of papillary carcinoma(26.1%, 6/23). The malignancy risks of categories 3, 4a, 4b, and 4c nodules were 0.9%, 4.6%, 10.0%, and 11.8%, respectively.

Conclusion

Large thyroid nodules with benign cytology had a relatively high false-negative risk of 3.6% and TIRADS was helpful in predicting false-negative cytology for these lesions.