Value of repeat ultrasound-guided fine-needle aspiration in nodules with benign cytological diagnosis

Value of repeated US-guided fine-needle aspiration (US-FNAB) in the follow-up of benign thyroid nodules: a real-life study based on the MoCyThy (Modena's Cytology of the Thyroid) DATABASE with a revision of the literature

PURPOSE

The utility of repeating ultrasound-guided fine-needle aspiration (US-FNAB) in the follow-up of benign (THY2) thyroid nodules is still debated. The aim of this study was to retrospectively investigate the diagnostic value of re-biopsy of thyroid nodules following an initially benign result.

METHODS

We retrospectively analyzed US-FNABs performed at the Unit of Endocrinology of Modena from 2006 to 2009. The firstly benign cytological result was compared with the cytological results of subsequent US-FNABs (2nd and/or 3rd) executed on the same nodule.

RESULTS

Among 10449 US-FNABs, 6270 (60%) received a THY2 cytological categorization. Of them, 278 (4.43%) underwent a subsequent US-FNAB: 86.7% maintained the same cytology, 32 (11.5%) changed to THY3 (indeterminate) and 5 (1.8%) to THY4 (suspicious of malignancy). Among the 24 nodules addressed to surgery, 9 (37%) were histologically malignant, with an overall miss rate of 3.2%. Male patients had higher risk of discordant results at subsequent US-FNAB (p = 0.005, OR:3.59, 95%CI:1.453-7.769) while dimensional increase above 5 mm was predictive of concordant benign cytology (p = 0.036, OR:0.249, 95%CI:0.068-0.915). Age, suspicious US characteristics, and distance between US-FNABs resulted not predictive.

CONCLUSIONS

Re-biopsy of benign nodules confirmed the benign nature in most cases. In case of discordant cytology, relocation in indeterminate category was the most common. The histological diagnosis of cancer occurred in one quarter of nodules surgically removed, with a low overall clinically significant miss rate. Thus, a small percentage of false negatives exists; males and subjects with US suspicious nodules should be carefully followed-up, considering case by case re-biopsy possibility.

Degenerating Thyroid Nodules: Ultrasound Diagnosis, Clinical Significance, and Management

Degenerating nodules (DNs), which primarily manifest as benign thyroid nodules, are one of the main causes of discordance in ultrasonography (US) and cytological assessments. Intranodular hemorrhage is one of the mechanisms contributing to discordant nodules, and an impaired blood supply may explain further DN shrinkage and infarction. The surgical specimens can be divided into acute and chronic stages based on the histological changes, which usually mimic the US features of malignant tumors. Serial US follow-up should be recommended instead of other unnecessary procedures. However, repeated fine-needle aspiration, diagnostic surgery, or core-needle biopsy may still be necessary for indeterminable or highly suspicious DNs.

Utility of Preoperative Ultrasonography in Transferred Patients with Suspicious Malignancy on Ultrasonography-Guided Fine-Needle Aspiration Cytology of Thyroid Nodules: A Single-Center Retrospective Study

Background

This study aimed to assess the utility and characteristics of preoperative ultrasonography (US) in patients transferred to referral hospitals from local clinics with a diagnosis of malignancy on US-guided fine-needle aspiration cytology of thyroid nodules.

Material/Methods

From January 2018 to June 2018, 109 transferred patients underwent preoperative US in our hospital for suspected thyroid malignancy on cytological analysis after US-guided fine-needle aspiration of thyroid nodules in local clinics. Preoperative US was performed by a single radiologist in all patients. Among them, 6 were excluded from the study because of refusal of thyroid surgery. Preoperative US and histopathological results were compared in all patients.

Results

After thyroid surgery, pathological examination revealed papillary thyroid carcinoma (PTC) (n=98), follicular adenoma (n=1), and nodular hyperplasia (n=4). Of the 103 patients, 91 exhibited suspicious US findings on the preoperative US, whereas 12 did not. In the 91 patients with suspicious US findings, PTC (n=90) and follicular adenoma (n=1) were confirmed after thyroid surgery. In the 12 patients with no suspicious US findings, PTC (n=8) and nodular hyperplasia (n=4) were confirmed after thyroid surgery. On repeat analysis of the cytological slides of the 4 nodular hyperplasia cases from the local clinics, Bethesda category II (n=1) and III (n=3) were determined.

Conclusions

In the transferred patients with a malignant cytology, preoperative US might be helpful to detect false-positive cytology cases.

The Role of Core Needle Biopsy for the Evaluation of Thyroid Nodules with Suspicious Ultrasound Features

Objective

Recent studies demonstrated that core needle biopsy (CNB) can effectively reduce the possibility of inconclusive results and prevent unnecessary diagnostic surgery. However, the effectiveness of CNB in patients with suspicious thyroid nodules has not been fully evaluated. This prospective study aimed to determine the potential of CNB to assess thyroid nodules with suspicious ultrasound (US) features.

Materials and Methods

Patients undergoing CNB for thyroid nodules with suspicious features on US were enrolled between May and August 2016. Diagnostic performance and the incidence of non-diagnostic results, inconclusive results, conclusive results, malignancy, unnecessary surgery, and complications were analyzed. Subgroup analysis according to nodule size was performed. The risk factors associated with inconclusive results were evaluated using multivariate logistic regression analysis.

Results

A total of 93 patients (102 thyroid nodules) were evaluated. All samples obtained from CNB were adequate for diagnosis. Inconclusive results were seen in 12.7% of cases. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value for diagnosis of malignancy were 93.8%, 100%, 100%, 78.9%, and 95%, respectively. None of the patients underwent unnecessary surgery. The diagnostic performance was not significantly different according to nodule size. On multivariate logistic regression analysis, larger nodule size and shorter needle length were independent risk factors associated with inconclusive results.

Conclusion

Samples obtained by CNB were sufficient for diagnosis in all cases and resulted in high diagnostic values and conclusive results in the evaluation of suspicious thyroid nodules. These findings indicated that CNB is a promising diagnostic tool for suspicious thyroid nodules.

Malignancy risk of initially benign thyroid nodules: validation with various Thyroid Imaging Reporting and Data System guidelines

OBJECTIVE

Some authors have found little or no diagnostic benefit from repeated biopsy of benign thyroid nodules. However, to our knowledge, integration of Thyroid Imaging Reporting and Data System (TIRADS) guidelines with one biopsy for sufficient benign thyroid nodule diagnosis has not been previously described. We investigated malignancy rate and probability by using various malignancy stratification systems in initially biopsy-proven benign nodules and sought to determine their clinical relevance in management of benign thyroid nodules.

METHODS

This retrospective study collected 6762 thyroid nodules from 6493 consecutive patients who underwent biopsy between January 2013 and December 2013. The initial biopsy with ≥1 year of follow-up was used as the gold standard for benign diagnosis. For our study purpose, we analyzed 2747 (57.0%, 2747 of 4822, 532 women, 2111 men; 229 malignant and 2518 benign) thyroid nodules diagnosed by initial biopsy with 28.2 ± 9.1 (range, 12-41) months of follow-up. We calculated the malignancy probability of thyroid nodules by using various malignancy risk stratification systems.

RESULTS

The overall calculated thyroid malignancy rate was 8.3% (229 of 2747). Initially biopsy-proven benign nodules exhibited a ≤3.0% malignancy probability when assessed as "low suspicion" by Korean-TIRADS (K-TIRADS), "low suspicion" by the ATA guideline, and "very probably benign" by the French TIRADS guideline and gave a score of ≤3 by the web-based TIRADS.

CONCLUSION

When initially biopsy-proven benign nodules exhibit a "low suspicion" US pattern and low malignancy probability, as stratified by various TIRADS guidelines, imaging surveillance instead of second biopsy is warranted.

KEY POINTS

• One biopsy is sufficient for initially biopsy-proven benign nodules. • Repetitive biopsy is necessary for imaging-pathology mismatched nodules. • Scoring risk stratification permits personalized management.

Ultrasound-Pathology Discordant Nodules on Core-Needle Biopsy: Malignancy Risk and Management Strategy

BACKGROUND

The reported malignancy rates of thyroid nodules that appear suspicious on ultrasound (US) but yield benign fine-needle aspiration (FNA) cytology results range from 13.6% to 56.6%. However, the malignancy risk of nodules that are discordant on US and core-needle biopsy (CNB) pathological findings has not been evaluated. This study evaluated the malignancy risk associated with thyroid nodules that are suspicious on US but yield benign CNB results.

METHODS

Between July 2008 and November 2011, 1309 patients with 1313 thyroid nodules underwent US-guided CNB. Among these, 166 thyroid nodules that were suspicious on US but yielded benign CNB results were retrospectively reviewed. Benign nodules were diagnosed by surgery, FNA, and/or CNB that was repeated at least twice or CNB and lesion size stability on follow-up. The malignancy risk of US-pathology discordant nodules was calculated according to recommendations by Moon et al., and a further evaluation was conducted using four different US risk systems. Factors that differentiated benign from malignant nodules were assessed using the chi-square test or Fisher's exact test. Moreover, the histological findings of US-pathology discordant nodules were analyzed.

RESULTS

Patients with benign and malignant nodules did not differ significantly regarding clinical and demographic characteristics. Of the 166 US-pathology discordant nodules, seven (4.2%) were confirmed malignant. The malignancy risks associated with the five US risk systems ranged from 3.6% to 5.5%. Regarding suspicious US features, only the number of suspicious features was associated with malignancy (p = 0.002). Histological analysis of benign CNB specimens with suspicious US features revealed fibrosis (77.6%), thyroiditis (28.7%), calcifications (10.6%), and hemosiderin deposition (6.4%).

CONCLUSIONS

The malignancy risk among thyroid nodules with discordant US and CNB results ranged from 3.6% to 5.5%, depending on US risk systems. However, repeated biopsy may be necessary for selected thyroid nodules with more than two suspicious US features.

Core Needle Biopsy of the Thyroid: 2016 Consensus Statement and Recommendations from Korean Society of Thyroid Radiology

Core needle biopsy (CNB) has been suggested as a complementary diagnostic method to fine-needle aspiration in patients with thyroid nodules. Many recent CNB studies have suggested a more advanced role for CNB, but there are still no guidelines on its use. Therefore, the Task Force Committee of the Korean Society of Thyroid Radiology has developed the present consensus statement and recommendations for the role of CNB in the diagnosis of thyroid nodules. These recommendations are based on evidence from the current literature and expert consensus.

Ultrasonography Diagnosis and Imaging-Based Management of Thyroid Nodules: Revised Korean Society of Thyroid Radiology Consensus Statement and Recommendations

The rate of detection of thyroid nodules and carcinomas has increased with the widespread use of ultrasonography (US), which is the mainstay for the detection and risk stratification of thyroid nodules as well as for providing guidance for their biopsy and nonsurgical treatment. The Korean Society of Thyroid Radiology (KSThR) published their first recommendations for the US-based diagnosis and management of thyroid nodules in 2011. These recommendations have been used as the standard guidelines for the past several years in Korea. Lately, the application of US has been further emphasized for the personalized management of patients with thyroid nodules. The Task Force on Thyroid Nodules of the KSThR has revised the recommendations for the ultrasound diagnosis and imaging-based management of thyroid nodules. The review and recommendations in this report have been based on a comprehensive analysis of the current literature and the consensus of experts.

Focal Lymphocytic Thyroiditis Nodules Share the Features of Papillary Thyroid Cancer on Ultrasound

PURPOSE

It is often difficult to discriminate focal lymphocytic thyroiditis (FLT) or adenomatous hyperplasia (AH) from thyroid cancer if they both have suspicious ultrasound (US) findings. We aimed to make a predictive model of FLT from papillary thyroid cancer (PTC) in suspicious nodules with benign cytologic results.

MATERIALS AND METHODS

We evaluated 214 patients who had undergone fine-needle aspiration biopsy (FNAB) and had shown thyroid nodules with suspicious US features. PTC was confirmed by surgical pathology. FLT and AH were confirmed through more than two separate FNABs. Clinical and biochemical findings, as well as US features, were evaluated.

RESULTS

Of 214 patients, 100 patients were diagnosed with PTC, 55 patients with FLT, and 59 patients with AH. The proportion of elevated thyrotropin (TSH) levels (p=0.014) and thyroglobulin antibody (Tg-Ab) or thyroid peroxidase antibody (TPO-Ab) positivity (p<0.001) in the FLT group was significantly higher than that in the PTC group. Regarding US features, absence of calcification (p=0.006) and "diffuse thyroid disease" (DTD) pattern on US (p<0.001) were frequently seen in the FLT group. On multivariate analysis, Tg-Ab positivity, presence of a DTD pattern on US, and absence of calcification in nodules were associated with FLT with the best specificity of 99% and positive predictive value of 96%. In contrast, a taller than wide shape of nodules was the only variable significant for differentiating AH from PTC.

CONCLUSION

Suspicious thyroid nodules with cytologic benign results could be followed up with US rather than repeat FNAB, if patients exhibit Tg-Ab positivity, no calcifications in nodules, and a DTD pattern on US.

[Repeated fine-needle aspiration cytology for the diagnosis and follow-up of thyroid nodules]

INTRODUCTION

The recently-proposed Bethesda reporting system has offered clinical recommendations for each category of reported thyroid cytology, including repeated fine-needle aspiration (FNA) for non-diagnostic and atypia/follicular lesions of undetermined significance, but there are no sound indications for repeated examination after an initial benign exam.

OBJECTIVE

To investigate the clinical validity of repeated FNA in the management of patients with thyroid nodules.

METHOD

The present study evaluated 412 consecutive patients who had repeated aspiration biopsies of thyroid nodules after an initial non-diagnostic, atypia/follicular lesion of undetermined significance, or benign cytology.

RESULTS

The majority of patients were female (93.5%) ranging from 13 to 83 years. Non-diagnostic cytology was the most common indication for a repeated examination in 237 patients (57.5%), followed by benign (36.8%), and A/FLUS (5.6%) cytology. A repeated examination altered the initial diagnosis in 70.5% and 78.3% of the non-diagnostic and A/FLUS patients, respectively, whereas only 28.9% of patients with a benign cytology presented with a different diagnosis on a sequential FNA.

CONCLUSIONS

Repeat FNA is a valuable procedure in cases with initial non-diagnostic or A/FLUS cytology, but its routine use for patients with an initial benign examination appears to not increase the expected likelihood of a malignant finding.

Malignancy risk stratification in thyroid nodules with benign results on cytology: combination of thyroid imaging reporting and data system and Bethesda system

BACKGROUND

The indications of repeat fine-needle aspiration (FNA) for thyroid nodules with benign results of the Bethesda system were investigated.

METHODS

A total of 1,398 nodules were classified according to the Thyroid Imaging Reporting and Data System (TIRADS). TIRADS category 3 included nodules without solidity, hypoechogenicity or marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, and taller-than-wide shape on ultrasonography (US). Categories 4a, 4b, 4c, and 5 included nodules with one, two, three or four, or five suspicious US features, respectively. The malignancy risks, and odds ratio (OR) with 95 % confidence interval (CI) were calculated. Analyses were performed for all nodules, nodules >10 mm, and nodules ≤10 mm.

RESULTS

Of 1.398 nodules, 43 (3.1 %) were malignanct. The malignancy risks of benign nodules with categories 3, 4a, and 4b were 0.7, 1.2, and 0.7 %, respectively, whereas those for nodules with categories 4c and 5 were 9.8 and 22.2 %, respectively. The ORs of nodules with categories 4c and 5 were 19.4 (95 % CI 5.0-76.2) and 50.6 (95 % CI 10.4-245.0), respectively. In nodules >10 mm, the malignancy risks of categories 4c and 5 were 2.7 and 20 %, respectively, and the ORs were 10.7 (95 % CI 1.2-93.7) and 236.1 (95 % CI 12.6-4426.4), respectively. In nodules ≤ 10 mm, the malignancy risks of categories 4c and 5 were 12.6 and 22.6 %, respectively, and the ORs were 10.1 (95 % CI 1.3-78.0) and 18.9 (95 % CI 2.1-168.9), respectively.

CONCLUSIONS

Repeat US-guided FNA should be considered in benign thyroid nodules with three or more suspicious US features regardless of size.

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.

Thyroid nodule with benign cytology: is clinical follow-up enough?

Objective

In this multicenter study, we investigated the management algorithm for thyroid nodules with benign cytology using US features from data collected from 7 institutions.

Materials and Methods

The institutional review board approved this retrospective study. Data on 700 focal thyroid nodules in 673 consecutive patients were collected from 7 university-affiliated hospitals. This study included nodules that were diagnosed as benign at initial cytologic evaluation and that underwent pathologic or follow-up study. The risk of malignancy was compared according to the US assessments of each institution as well as looking at all the nodules together as a whole.

Results

Of the 700 nodules, 688 (98.3%) were benign and 12 (1.7%) were malignant. If initial cytologic results were benign, the likelihood of the nodule actually being malignant was from 1 to 3%, varying by institution. The likelihood of a cytologically benign nodule with positive US being malignant (4.7%, 8/169) was higher than that of one without positive US (0.8%, 4/531) (P = .002).

Conclusion

Based on our multicenter study, repeat FNA should be performed in thyroid nodules with initial benign cytology showing suspicious US features in order to decrease the number of false negative cases.

Initially non-diagnostic ultrasound-guided fine needle aspiration cytology of thyroid nodules: value and management

BACKGROUND

Ultrasound (US)-guided fine needle aspiration cytology (FNAC) is an accurate, reliable, and simple method to identify a thyroid nodule as benign or malignant. However, non-diagnostic cytology results for thyroid nodules are a major limitation of US-guided FNAC.

PURPOSE

To investigate the incidence of thyroid cancer among cases with non-diagnostic results on FNAC and to provide suggestions for the management of thyroid nodules that are initially non-diagnostic by FNAC according to ultrasonographic findings.

MATERIAL AND METHODS

From July 2006 to December 2009, 10,317 thyroid nodules in 6684 consecutive patients underwent US-guided FNAC at our institute. Among these, 871 thyroid nodules (8.4%) were diagnosed as non-diagnostic on initial cytologic evaluation and 196 underwent a second or third FNAC. Twenty-seven thyroid nodules (18.9%) underwent surgery, while 116 thyroid nodules were cytologically confirmed as benign with no remarkable change on follow-up US were included. We retrospectively reviewed the US findings for a total of 143 thyroid nodules (123 benign nodules and 20 malignant nodules). The US features that we compared included composition, echogenicity, margin, calcifications, shape, and underlying echogenicity.

RESULTS

In total, thyroid cancer was diagnosed in 20 nodules (14.0%). The size of the nodule was significantly associated with malignancy (P < 0.05). Most of the sonographically probable benign nodules were found to be benign (97.6%). Suspicious nodules on US were thyroid cancer in 43.2% of cases. Marked hypoechogenicity, microlobulated or irregular margin, microcalcifications, and taller-than-wide shape were significant US findings that correlated with malignancy (P < 0.05). The diagnostic performance of ultrasound for initially non-diagnostic thyroid nodules was as follows: sensitivity of 90.0%, specificity of 65.0%, positive predictive value of 29.5%, and negative predictive value of 97.6%.

CONCLUSION

In terms of management of thyroid nodules with non-diagnostic FNAC cytology, US evaluation is a feasible and useful method for predicting malignancy.

Suspiciously malignant findings on ultrasound after fine needle aspiration biopsy in a thyroid nodule with initially benign ultrasound and cytologic result: to repeat or to follow-up

PURPOSE

The purposes of this study were to evaluate the incidence of suspiciously malignant change on ultrasound (US) in thyroid nodules after initial benign US and cytologic results and to investigate the associated US characteristics and the management of these nodules.

MATERIALS AND METHODS

Among the patients who underwent thyroid fine needle aspiration biopsy (FNAB) from October 2003 to December 2004, 550 patients who had thyroid nodules with initial benign US and cytologic results were included. Reference standards were established by pathologic results, follow-up cytologic results or follow-up US. We evaluated the incidence of morphologic changes to suspiciously malignant US findings of these thyroid nodules after FNAB. We also evaluated the initial US features associated with the nodules showing suspiciously malignant findings on US after FNAB in these patients.

RESULTS

Of 550 patients, 28 nodules (5.1%) showed morphologic changes into nodules with suspiciously malignant US findings on follow-up US. All thyroid nodules showing morphologic changes had mixed solid and cystic components (P<.001). Suspiciously malignant changes on US were associated with the percentage of the cystic portion, but all changed nodules were confirmed as benign.

CONCLUSION

Follow-up US should be recommended rather than to repeat FNAB for thyroid nodules with initial benign US and cytologic results even if they later develop suspiciously malignant US features after FNAB.

Value of repeat ultrasound-guided fine-needle aspiration in thyroid nodule with a first benign cytologic result: impact of ultrasound to predict malignancy

This study aimed to investigate the value of repeat ultrasound-guided fine-needle aspiration (FNAC-US) in benign thyroid nodules and determine the ultrasound (US) predictors of malignancy in this group of nodules. The authors studied 35 of 143 nodules with initially benign cytological result who underwent serial re-biopsy (FNAC-US). By means of surgery, malignancy histology results were confirmed in 10 (28.5%) cases (G1) versus 25 (71.5%) benign nodules (G2). The clinical, lab, scintigraphyc, and US features were compared between the two groups to predict malignancy in thyroid nodules with initially benign cytological result. The cytological finding of 28/35 nodules were change to indeterminate cytology (Bethesda system category III or IV) at second and/or ≥third cytological study. In this group of 28 cases, 23 (82.1%) was identified until the third procedure. The interval between first and third re-biopsy was 13 months (median). There were no differences in age, gender, thyrotropin (TSH) levels, thyroid auto-antibodies, or thyroid dysfunctions. The scintigraphy showed cold nodule in 80% of G1 versus 78.9% of G2 (NS). Sonographic studies showed malignant suspected US features in G1: microcalcifications, central flow, hypoechogenicity, and border irregularity. This study suggests repeating FNAC-US in nodules with first benign cytologic result and suspicious US features of malignancy for at least two times (until the third FNAC) in about 13 months horizon.

Fine-needle aspiration of follicular patterned lesions of the thyroid: Diagnosis, management, and follow-up according to National Cancer Institute (NCI) recommendations

The National Cancer Institute (NCI) State of the Science Conference on thyroid fine-needle aspiration (FNA) proposed that follicular patterned lesions can be divided into two diagnostic categories; follicular lesion of undetermined significance/Atypia of undetermined significance (FLUS/AUS) and suspicious for follicular neoplasm/follicular neoplasm (SFON/FON). The former group can benefit from repeat FNA (RFNA) to achieve a more definitive diagnosis and the latter should undergo surgical excision for histologic characterization (adenoma vs. carcinoma). In this study, we report the combined experience from our institutions with thyroid FNA cases that can be placed into NCI-designated thyroid FNA diagnostic categories for follicular patterned lesions.The case cohort comprised of 857 cases in 645 females and 212 males; 509 cases could be classified as FLUS/AUS and 348 as SFON/FON. Histologic follow-up was available in 273/509 (54%) cases diagnosed as FLUS/AUS and 251/348 (72%) cases diagnosed as SFON/FON.RFNA was performed in 203/509 (40%) patients classified as FLUS/AUS. RFNA diagnoses were: benign (125 cases), FLUS (46 cases), SFON/FON (20 cases), suspicious for papillary carcinoma (7 cases), papillary carcinoma (3 cases) and non-diagnostic (2 cases). The malignancy rate on surgical excision in the FLUS/AUS group was 27 and 15% with and without RFNA, respectively; and 25% in cases diagnosed as SFON/FON.RFNA is effective in managing thyroid nodules diagnosed as FLUS/AUS since the malignancy rates are different in cases with or without RFNA (27% vs. 15%). The malignancy rate (25%) in cases diagnosed as SFON/FON is similar to reported by other authors.

Ultrasonographic characteristics as a criterion for repeat cytology in benign thyroid nodules

OBJECTIVE: To report the results of repeat fine-needle aspiration cytology (FNAC) in thyroid nodules with an initial benign cytological diagnosis that grow during follow-up and/or present suspicious ultrasonographic characteristics. SUBJECTS AND METHODS: The sample consisted of 456 patients with 895 nodules. FNAC was repeated after 12 to 18 months in the case of nodules with suspicious ultrasonographic characteristics, irrespective of growth, and when the nodules showed significant growth. RESULTS: Among the 895 nodules examined, 102 (11.4%) presented suspicious ultrasonographic characteristics. The second FNAC revealed malignancy in 18 (17.6%) nodules, including 20% (2/10) of those showing growth and 17.4% (16/92) that did not. Seventy-six (9.6%) of 793 nodules without suspicious characteristics presented growth. Only one case (1.3%) of malignancy was diagnosed by repeat FNAC. CONCLUSIONS: The study suggests ultrasonographic characteristics rather than growth as a criterion for repeat FNAC in the case of nodules with an initial benign cytological diagnosis.

Value of US correlation of a thyroid nodule with initially benign cytologic results

PURPOSE

To investigate the value of ultrasonographic (US) features in thyroid nodules with initially benign cytologic results.

MATERIALS AND METHODS

The institutional review board approved this retrospective study and required neither patient approval nor informed consent for the review of images and records. From October 2003 to February 2006, 6118 focal thyroid nodules in 6025 consecutive patients underwent US-guided fine-needle aspiration biopsy (FNAB). This study included 1343 nodules 1 cm or larger in 1302 patients that were diagnosed as benign at initial cytologic evaluation and underwent pathologic or follow-up study. We compared the risk of malignancy according to US findings and calculated the likelihoods of different subgroups having benign nodules.

RESULTS

In total, 26 (1.9%) malignant and 1317 (98.1%) benign nodules were found according to reference standards. If initial cytologic results showed benign thyroid nodules, the likelihood of the nodule actually being benign was 98.1%. When a thyroid nodule had benign results at both initial and repeat FNAB, the likelihood increased to 100%. The likelihood of having a benign thyroid nodule with suspicious US features was lower (79.6%) than having a benign thyroid nodule with negative US features (99.4%, P<.001). In the nodule with benign features at initial US, the risk of malignancy for a thyroid nodule with an increase in size at follow-up US was slightly higher (1.4%) than that of a thyroid nodule with no interval change or decrease in size, but it was not significantly different (0.5%, P = .354).

CONCLUSION

Repeat FNAB should be performed for thyroid nodules that have suspicious US features, even if the initial cytologic results indicate that it is a benign lesion.

Comparison of cytological results obtained by repeated US-guided fine-needle aspiration biopsies of thyroid nodules: focus on the rate of malignancy and diagnostic concordance

The debate still continues on the repeated fine-needle aspiration biopsies (FNABs) for thyroid nodule in clinical practice. In this study, we determined the rate of cytological change to malignancy and the diagnostic concordance of repeated FNABs when the same nodules were targeted under US-guidance. We retrospectively reviewed data for 187 thyroid nodules (173: twice, 14: three times) from 160 patients who underwent repeated US-guided FNABs, which were performed by one skillful radiologist targeting for the same nodules at a mean interval of 7.5 months. Their initial cytological findings were compared with second or third results and histopathologic follow-up. The initial FNABs findings of 187 nodules were unsatisfactory, benign, and indeterminate in 56, 52, and 79 cases, respectively. The rate of a second cytological diagnosis changed to malignancy was significantly higher in the unsatisfactory aspirates (10.7%; 6/56), when compared with those of the benign (0.0%; 0/52) or of indeterminate aspirates (3.8%; 3/79) (P = 0.022). However, there was no change to malignancy at third cytological findings of all 14 nodules. After the second US-guided FNABs, 30.8% (16/52) of the initially diagnosed as benign aspirates were reclassified as indeterminate, while 26.6% (21/79) of the initially diagnosed as indeterminate were reclassified as benign. In conclusion, to identify malignancies, repeated US-guided FNABs are recommended for thyroid nodules initially classified as unsatisfactory aspirates. However, although US-guidance is applied, a discrepancy might be unavoidable in the cytological interpretation of the nodules classified as benign or as indeterminate aspirates because of overlapping cytological criteria.

How to combine ultrasound and cytological information in decision making about thyroid nodules

The purpose of this study was to evaluate the role of sonographic-cytological correlation in determining which nodules should be reaspirated to reduce the false-negative rate of fine-needle aspiration biopsy (FNAB). A retrospective cohort study was performed on a database of 568 patients with 672 focal thyroid nodules. An independent two-sample t-test was used to compare the risk of malignancy according to clinical factors. We evaluated the risk stratification of malignancy according to US groupings and cytological results. Additionally, we calculated the false-negative rate of FNAB and investigated the cytological results of repeat aspiration. The malignancy rate (92.2-98.5%) was high in thyroid nodules designated "malignant" or "suspicious for papillary carcinoma" on FNAB, regardless of US features. In contrast, when focal thyroid nodules had "benign" readings on FNAB, the malignancy rate was lower for the "probably benign" US features (2.9%) than for the suspicious nodules (56.6%). The false-negative rate of FNAB was 5.8%. Repeat aspiration revealed "suspicious for malignancy" or "malignancy" results in 15 (93.8%) of 16 thyroid cancers with "benign" results on initial aspirate. This study demonstrated repeat FNAB should be performed on focal thyroid nodules with suspicious US features even when initial FNAB results are benign.

US-guided fine-needle aspiration of thyroid nodules: indications, techniques, results

Fine-needle aspiration (FNA) biopsy of thyroid nodules is minimally invasive and safe and is usually performed on an outpatient basis. However, the optimal application of FNA requires not only technical skill but also an awareness of the limitations of the procedure, the indications for its use, the factors that affect the adequacy of the biopsy specimen, and the postprocedural management strategy. Ultrasonographic (US) features that are considered indications for FNA include single and multiple thyroid nodules. The results of FNA biopsy are operator dependent. In addition, the results may be affected by the lesion characteristics, the accuracy of lesion and needle localization, the method of guidance, the number of aspirated samples, the needle gauge, the aspiration technique, and the presence or absence of on-site facilities for immediate cytologic examination. With regard to postprocedural management, nodules that are diagnosed as benign on the basis of an adequate FNA specimen should be monitored with follow-up US. Circumstances that necessitate repeat FNA include sample inadequacy, nodule enlargement, cyst recurrence, or clinical or imaging findings that arouse suspicion about the presence of a malignancy even when cytologic findings in the biopsy specimen indicate benignity. Supplemental material available at radiographics.rsnajnls.org/cgi/content/full/28/7/1869/DC1.

Diagnostic terminology and morphologic criteria for cytologic diagnosis of thyroid lesions: a synopsis of the National Cancer Institute Thyroid Fine-Needle Aspiration State of the Science Conference

The National Cancer Institute (NCI) sponsored the NCI Thyroid Fine-needle Aspiration (FNA) State of the Science Conference on October 22-23, 2007 in Bethesda, MD. The two-day meeting was accompanied by a permanent informational website and several on-line discussion periods between May 1 and December 15, 2007 (http://thyroidfna.cancer.gov). This document summarizes matters regarding diagnostic terminology/classification scheme for thyroid FNA interpretation and cytomorphologic criteria for the diagnosis of various benign and malignant thyroid lesions. (http://thyroidfna.cancer.gov/pages/info/agenda/).