Correlation between indeterminate aspiration cytology and final histopathology of thyroid neoplasms

Ultrasound is helpful to differentiate Bethesda class III thyroid nodules: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

Fine-needle aspiration (FNA) is the most dependable tool to triage thyroid nodules for medical or surgical management. However, Bethesda class III cytology, namely "follicular lesion of undetermined significance" (FLUS) or "atypia of undetermined significance" (AUS), is a major limitation of the US-FNA in assessing thyroid nodules. As the most important imaging method, ultrasound (US) has a high efficacy in diagnosing thyroid nodules. This meta-analysis aimed to assess the role of US in evaluating Bethesda class III thyroid nodules.

METHODS

With keywords "Undetermined Significance," "Bethesda Category III," "Bethesda system," "Cytological Subcategory," "AUS/FLUS," "Atypia of Undetermined Significance," and "Ultrasound/US," papers in PubMed, Cochrane Library, Medline, Web of Science, Embase, and Google Scholar from inception to December 2016 were searched. A meta-analysis of these trials was then performed for evaluating the diagnostic value of thyroid ultrasound in Bethesda Category III thyroid nodules.

RESULTS

Fourteen studies including 2405 nodules were analyzed. According to the criteria for US diagnosis of thyroid nodules in each article, with any one of suspicious features as indictors of malignancy, US had a pooled sensitivity of 0.75 (95% CI 0.72-0.78) and a pooled specificity of 0.48 (95% CI 0.45-0.50) in evaluating Bethesda Class III Nodules. The pooled diagnostic odds ratio was 10.92 (95% CI 6.04-19.74). The overall area under the curve was 0.84 and the Q* index was 0.77. With any 2 or 3 of US suspicious features as indictors of malignancy, the sensitivity and specificity were 0.77 (95% CI 0.71-0.83) and 0.54 (95% CI 0.51-0.58), 0.66 (95% CI 0.59-0.73) and 0.71 (95% CI 0.68-0.74), respectively.

CONCLUSIONS

US was helpful for differentiating benign and malignant Bethesda class III thyroid nodules, with the more suspicious features, the more likely to be malignant.

UTILITY OF ULTRASOUND VERSUS GENE EXPRESSION CLASSIFIER IN THYROID NODULES WITH ATYPIA OF UNDETERMINED SIGNIFICANCE

OBJECTIVE

Thyroid nodules with fine-needle aspiration (FNA) cytology categorized as atypia of undetermined significance (AUS) often undergo additional diagnostic analysis with the Afirma Gene Expression Classifier (GEC), which classifies these as either high probability of being benign (GEC-B) or suspicious for malignancy (GEC-S). Our goal was to assess the clinical validity and utility of GEC in the evaluation of AUS cytology and evaluate the performance of ultrasonography (USG) for predicting malignancy in this subset.

METHODS

We conducted a study with a retrospective cohort of patients from January 2012 to January 2014 who had FNA of thyroid nodules >1 cm in size with AUS cytology.

RESULTS

Cleveland Clinic Florida has an overall prevalence of AUS of 5%. A total of 119 cases with nodules >1 cm in size were reported as AUS. Forty-eight (40.3%) had a GEC performed after the first FNA (AUS-1), and 27 of these were GEC-S. Of those 27, 21 went for surgery and 14 (66.6%) had thyroid cancer on histopathology. The remaining 71 with AUS-1 were sent for a second FNA: 19 nodules were benign and did not undergo further evaluation, while the remaining 52 were reported as AUS for the second consecutive time (AUS-2). AUS-2 samples were sent for GEC. Of these 52 AUS-2, 38 (73.1%) were reported as GEC-S. Thirty-five went for surgery and 32 (91.4%) had confirmed malignancy on histopathology. Positive predictive value (PPV) was 91.4% for AUS-2 and 66.6% for AUS-1. Moreover, AUS-2 nodules that were hypoechoic and solid on USG showed a PPV of 92% for malignancy.

CONCLUSION

In our practice, the diagnostic accuracy to predict malignancy with GEC for AUS-1 nodules was poor (PPV, 66.6%). The PPV of GEC testing was markedly higher at 91.4% performed after two consecutive AUS cytologies. AUS-2 nodules that were solid and hypoechoic on USG also had a high probability to be malignant (PPV, 92%). We recommend repeat FNA on AUS-1 nodules rather than proceeding directly to GEC testing. Also, we suggest that among AUS-2 nodules, surgery can be recommended when USG shows solid and hypoechoic features with GEC testing reserved for the remainder.

ABBREVIATIONS

AUS = atypia of undetermined significance FNA = fine-needle aspiration GEC = gene expression classifier GEC-B = GEC-benign GEC-S = GEC-suspicious for malignancy NPV = negative predictive value PPV = positive predictive value USG = ultrasonography.

The role of ultrasound findings in the management of thyroid nodules with atypia or follicular lesions of undetermined significance

BACKGROUND

Atypia or follicular lesions of undetermined significance (AUS/FLUS) is a broad cytological category in the Bethesda system for classifying thyroid cytology. This study investigated the diagnostic accuracy of ultrasound (US) analysis of thyroid nodules with AUS/FLUS.

PATIENTS AND METHODS

Of 5062 subjects with nodules subjected to fine-needle aspiration cytology (FNACs) at our institution from January 2010 through May 2012, 383 met the Bethesda criteria for AUS/FLUS. After excluding subjects who had a history of thyroid cancer, who only underwent repeat FNA or who underwent no further examinations, we selected 249 subjects who had subsequently undergone a core-needle biopsy and/or surgery. Of these, 100 were found to have malignant nodules (40·2%), 122 had benign nodules (49%), and 27 had nodules with indeterminate status (10·8%). We compared specific US parameters, including size, location, content, shape, margin, echogenicity, echotexture and calcification across these subject groups.

RESULTS

Multivariate analysis revealed that malignancy was associated with taller-than-wide shape (TDW) (OR = 8·43, P = 0·002), ill-defined margin (OR = 3·23, P = 0·002) and marked hypoechogenicity. (OR = 3·61, P = 0·001). The specificity and positive predictive values of TDW were 98% and 90·6%,respectively. The specificity and positive predictive values of 'TDW and marked hypoechogenicity' were both 100%.

CONCLUSION

US findings play a complementary role in the diagnosis of thyroid nodules with AUS/FLUS. In case of highly suspicious US findings such as 'TDW and marked hypoechogenicity', could be very helpful in the diagnosis of malignancy.

Outcome of thyroid nodules characterized as atypia of undetermined significance or follicular lesion of undetermined significance and correlation with Ultrasound features and BRAF(V600E) mutation analysis

OBJECTIVE

We aimed to establish the malignancy rate of thyroid nodules initially characterized as atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS) and whether they differ according to histologic subcategory. We also investigated the value of ultrasound features that predict malignancy and BRAF(V600E) mutation analysis and suggest strategies for the management of AUS/FLUS nodules.

MATERIALS AND METHODS

A total of 165 AUS/FLUS nodules were investigated. There are nine histologic subcategories of AUS/FLUS nodules. We compared the risk of malignancy in thyroid nodules according to the histologic subcategory using ultrasound findings and of those exhibiting the BRAF(V600E) mutation.

RESULTS

The malignancy rate of nodules with an initial diagnosis of AUS/FLUS was 55.2% (91/165). The malignancy rates by histologic subcategory were 0% in groups 1 (0/2), 2 (0/3), 4 (0/3), 7 (0/3), and 8 (0/1); 76.5% (13/17) in group 3; 83.1% (59/71) in group 5; and 29.2% (19/65) in group 9. The malignancy rate of nodules with suspicious ultrasound features was 79.3% (73/92), and the malignancy rate of nodules with indeterminate ultrasound features was 24.7% (18/73). AUS/FLUS nodules exhibiting taller-than-wide shape, illdefined margins, and microcalcifications or macrocalcifications showed significantly higher odds ratios. The likelihood of BRAF(V600E) mutation-positive nodules showing malignancy was 97.5% (39/40), whereas 39.7% (25/63) of BRAF(V600E) mutation-negative nodules were malignant (p < 0.05).

CONCLUSION

The malignancy rate of AUS/FLUS nodules in our study cohort was higher than previously reported. Nodules with suspicious features on ultrasound had a higher malignancy rate than did those with indeterminate features on ultrasound. The malignancy rate differed according to histologic subcategory; therefore, management of AUS/FLUS nodules should be tailored according to histologic subcategory.

Application of the Bethesda System for Reporting Thyroid Cytopathology in the Eastern Province of Saudi Arabia: phase I pilot retrospective analysis

We analyzed and evaluated our adequacy rate and the classification of our thyroid aspirates using the Bethesda System for Reporting Thyroid Cytopathology (BSRTC). All thyroid fine needle aspirates that were collected or referred to our institution were reviewed and reclassified according to the BSRTC. The results were tabulated and analyzed. Those with histological resection were correlated with our revised cytopathological evaluation using the BSRTC. A total of 205 thyroid aspirates from 186 patients were reviewed. There were 149 females (80%) and 37 males (20%) ranging in age from 23 to 81 (average age 48) years. All slides were reclassified using the BSRTC. The previous interpretations were not consistent with any apparent standards. The nondiagnostic rate was found to be 22%. Five cases were considered false negative and were upgraded to a more serious category with higher risk of malignancy. The high unsatisfactory rates can be reduced by an adequacy interpretation at the time of the procedure. The risk of malignancy in our cohort increased with each increase in the BSRTC category (I-VI). Communication about and awareness of the BSRTC and its implications by all our clinicians is a prime target of this study and is still work in progress. Hopefully, this study will increase the awareness of the BSRTC and its intended benefits in our region.

Thyroid nodules with Bethesda system III cytology: can ultrasonography guide the next step?

BACKGROUND

This study was designed to evaluate the feasibility and the role of thyroid ultrasound (US) in predicting malignancy for Bethesda system III nodules and to suggest management guidelines for these nodules.

METHODS

A total of 155 thyroid nodules with Bethesda system III cytology in 155 patients with surgery or follow-up repeat FNA were included in this study. On the basis of US features, final assessment for thyroid nodules were prospectively classified into one of three categories: (1) probably benign, (2) low suspicious for malignancy, and (3) suspicious for malignancy. The clinicopathologic characteristics of patients and US features of nodules were compared according to malignancy and benignity.

RESULTS

Of the 155 Bethesda system III nodules, 69 (44.5%) underwent surgery without repeat FNA and 86 (55.5%) nodules underwent repeat FNA, and a malignancy rate of 55.5% (86/155) was determined. Thyroid nodules with concurrent thyroid cancer were more likely to be malignant (P<0.001). The malignancy rate of sonographically suspicious for malignancy was 100%, higher than the 58% of sonographically low suspicious for malignancy, and 7.7% of sonographically probably benign nodules (P<0.001).

CONCLUSIONS

US assessment may help the clinician decide between surgery and repeat FNA for managing Bethesda system III nodules. When the US assessment for the thyroid nodules is suspicious for malignancy, repeat FNA may be unnecessary and surgery should be considered.

German Association of Endocrine Surgeons practice guideline for the surgical management of malignant thyroid tumors

INTRODUCTION

Over the past years, the incidence of thyroid cancer has surged not only in Germany but also in other countries of the Western hemisphere. This surge was first and foremost due to an increase of prognostically favorable ("low risk") papillary thyroid microcarcinomas, for which limited surgical procedures are often sufficient without loss of oncological benefit. These developments called for an update of the previous practice guideline to detail the surgical treatment options that are available for the various disease entities and tumor stages.

METHODS

The present German Association of Endocrine Surgeons practice guideline was developed on the basis of clinical evidence considering current national and international treatment recommendations through a formal expert consensus process in collaboration with the German Societies of General and Visceral Surgery, Endocrinology, Nuclear Medicine, Pathology, Radiooncology, Oncological Hematology, and a German thyroid cancer patient support organization.

RESULTS

The practice guideline for the surgical management of malignant thyroid tumors includes recommendations regarding preoperative workup; classification of locoregional nodes and terminology of surgical procedures; frequency, clinical, and histopathological features of occult and clinically apparent papillary, follicular, poorly differentiated, undifferentiated, and sporadic and hereditary medullary thyroid cancers, thyroid lymphoma and thyroid metastases from primaries outside the thyroid gland; extent of thyroidectomy; extent of lymph node dissection; aerodigestive tract resection; postoperative follow-up and surgery for recurrence and distant metastases.

CONCLUSION

These evidence-based recommendations for surgical therapy reflect various "treatment corridors" that are best discussed within multidisciplinary teams and the patient considering tumor type, stage, progression, and inherent surgical risk.

A histological assessment of the Bethesda system for reporting thyroid cytopathology (2010) abnormal categories: a series of 219 consecutive cases

OBJECTIVE

The purposes of this study were to establish the distribution of thyroid lesions that were seen in Hatay (a province of southern Turkey), to review the accuracy of fine needle aspiration cytology (FNAC) in the diagnosis of thyroid nodules and to correlate the FNAC results with the histopathology of the excised specimens, especially in indeterminate cases.

METHODS

Data on patient cytology were retrieved by a retrospective search of all thyroid FNAC specimens that had been evaluated at the Department of Pathology, Antakya Public Hospital, Hatay, Turkey between January 2009 and February 2011; 1021 thyroid FNAC samples were reviewed and interpretations were recorded according to the Bethesda system for reporting thyroid cytopathology (TBSRTC). The results of adequate FNAC samples were compared with the histological diagnoses in the cases in which surgery was performed, and the malignancy rates, especially in indeterminate categories, were calculated.

RESULTS

Of the 1021 FNAC samples, 697 (68.3%) were benign, 122 (11.9%) were non-diagnostic, 100 (9.8%) were atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 41 (4%) were follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), 36 (3.5%) were suspicious for malignancy (SM) and 25 (2.4%) were malignant. In 219 cases, there was follow-up histology. Rates of malignancy were as follows: benign, 0%; AUS/FLUS, 12.7%; FN/SFN, 35.0%; SM, 91.4%; malignant, 100%.

CONCLUSIONS

In our study, the cytohistological correlation of benign and malignant lesions was 100%. In the indeterminate categories, we recommend that clinicians should evaluate both the clinical and radiological findings of patients in addition to the FNAC results.

Role of sonographic diagnosis in managing Bethesda class III nodules

BACKGROUND AND PURPOSE

Bethesda class III cytology is an important limitation of the US-FNA in assessing thyroid nodules. This study aimed to assess the diagnostic efficacy of US in evaluating thyroid nodules with Bethesda class III cytology.

MATERIALS AND METHODS

From January 2008 to December 2009, 1036 patients with 1289 thyroid nodules diagnosed by US and subsequent US-FNA biopsy were enrolled in the study. On the basis of US features, each thyroid nodule was prospectively classified by a single radiologist into 1 of 5 diagnostic categories: benign, probably benign, borderline, possibly malignant, and malignant. Solid nodules were classified by using all 5 categories, whereas partially cystic nodules were classified by using 4 (borderline was omitted). We calculated the diagnostic efficacy of thyroid US by comparing the US diagnoses with the histopathology results of Bethesda class III nodules.

RESULTS

Of the 51 Bethesda class III nodules, 35 were surgically confirmed and 8 were histologically diagnosed, and a malignancy rate of 46.5% (20/43) was determined. From the 43 nodules, the sensitivity, specificity, positive and negative predictive values, and accuracy were calculated with 9 borderline nodules excluded (100%, 94.7%, 93.3%, 100%, and 97.0%, respectively) and with the 9 when reclassified as benign (63.6%, 95.2%, 93.3%, 71.4%, and 79.1%, respectively) and malignant (100%, 85.7%, 88.0%, 100%, and 93.0%, respectively). The values obtained with exclusion and malignancy reclassification of 9 borderline nodules were not significantly different (P = .250).

CONCLUSIONS

US diagnosis by using the present US classification system can be helpful for managing Bethesda class III nodules.

Review of atypical cytology of thyroid nodule according to the Bethesda system and its beneficial effect in the surgical treatment of papillary carcinoma

Purpose

For the atypical cases of fine needle aspiration (FNA) cytology of thyroid nodules, ultrasonographic findings are a primary guideline for the surgical treatment. However, they have the intrinsic risk of overtreatment, as well. In this study we examined whether the Bethesda system could provide a real effect on the diagnostic rate of atypical cytology, and thereby reduce the number of cases diagnosed as atypical from FNA cytology.

Methods

We reviewed 166 cases diagnosed as atypical by FNA cytology at this institute between the years 2005 to 2010. We classified these cases on the basis of ultrasonographic and cytological findings and compared them with the histological results.

Results

Ultrasonographically, findings suspicious for malignancy and indeterminate were associated with 83.7% and 47.2% of malignancy rates, respectively. Cytopathologically, the malignancy rates varied according to the main cytological features and the highest malignancy rate was 77.3%. Based on the Bethesda system, 39.2% of the cases diagnosed as atypical could be grouped into the category of suspicious for malignancy and yielded a malignancy rate of 76.9%.

Conclusion

Although ultrasonography provides an excellent guideline for the surgical treatment of atypical cases, it also showed considerable risk of overtreatment. The Bethesda system did not offer definitive effects on the rate of atypical cytology, but this system seemed to provide stricter boundaries for the atypical cytology and to aid in reducing the rates thereof. This in turn may permit that more limited cases are allotted to ultrasonographic decision making.

The atypical thyroid fine-needle aspiration: past, present, and future

Thyroid fine-needle aspiration has developed into a key test in the evaluation of thyroid nodules. Although the interpretation of thyroid aspirates containing mild abnormalities is problematic, the introduction of the atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) category in The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) has helped to delineate such cases in a systematic and clinically meaningful manner. Herein the authors review the cytomorphologic features associated with the AUS/FLUS interpretation and summarize the results of studies conducted since the implementation of TBSRTC.

Muc-1 expression may help characterize thyroid nodules but does not predict patients' outcome

Our purpose was to evaluate MUC1 clinical utility in the diagnosis and prognosis of thyroid cancer patients. We studied the protein expression of MUC1 in 289 thyroid carcinomas and 121 noncancerous thyroid nodules. There were 41 follicular carcinomas (FC) and 248 papillary thyroid carcinomas (PTC) including 149 classic (CPTC), 20 tall cell (TCPTC) and 79 follicular variants (FVPTC). In addition, we used a quantitative real-time PCR (q-PCR) method to measure MUC1 mRNA expression levels in 108 carcinomas, 23 hyperplasias, and 19 FA. According to their serum Tg levels and other evidences of recurrence/metastasis, the patients were classified as free-of-disease (185 cases) or bad outcome (56 cases, 10 deaths). MUC1 protein was identified in 80.2% PTC; 48.8% FC; 68.3% FVPTC; 70% TCPTC; 21.8% FA; 30% hyperplasias and 6% normal thyroid tissues. MUC1 distinguished benign from malignant thyroid tissues (sensitivity = 89%; specificity = 53%). MUC1 also differentiated FC from FA (p = 0.0083). q-PCR mRNA expression of MUC1 also distinguished malignant from benign nodules (Mann-Whitney test, p < 0.0001). However, neither IHC nor mRNA MUC1 expression was associated with any clinical or pathological feature of aggressiveness or outcome. We suggest that MUC1 expression may help differentiate follicular patterned thyroid lesions.