Nondiagnostic fine needle aspiration biopsy of the thyroid gland: a diagnostic dilemma

Diagnostic Value of Preparing Additional Liquid-Based Cytology Slides and Cell Blocks from Residue Material in Thyroid fine Needle Aspiration

Background and Aims

After liquid-based cytology (LBC) technique developed for cervical cytology, it has been used for nongynecological samples and has been very successful. It offers having extra slides of the samples for further examination and ancillary tests. Moreover, cell blocks can be formed from the residue material. The study aimed to evaluate the importance of preparing a second LBC slide or a cell block from the residue material of thyroid fine needle aspiration (FNA) samples to reach a definitive diagnosis in cases diagnosed as nondiagnostic (ND) after the first slide.

Material and Methods

Seventy five cases diagnosed as ND after the first slide were included in study. For 50 cases, the second LBC slides were prepared (LBC group); for 25 cases, cell block was performed from residue material (CB group). Two groups were compared in terms of reaching a definitive diagnosis.

Results

At the end of secondary procedures, a definitive diagnosis was reached in a total of 24 cases (32%). Twenty of 50 cases (40%) in LBC group reached a definitive diagnosis while four cases (16%) in the CB group reached a definitive diagnosis. Achieving a definitive diagnosis was found statistically higher in the LBC group in which the second slide was formed compared to the CB group (P =0.036).

Conclusion

Preparing a second slide with LBC method is more purposive than preparing a cell block from the residue material of thyroid FNA samples. Reducing the percentage of ND cases will protect patients from complications and morbidity that may arise from repeated FNA.

Punção Aspirativa da Tireóide por Agulha Fina. Correlação Cito-Histológica: Estudo Baseado em 50 Casos

O objetivo deste estudo foi o de avaliar a eficácia da punção aspirativa por agulha fina (PAAF) da tireóide comparando-a com o diagnóstico histopatológico. Os autores avaliaram os resultados citológicos de 50 pacientes atendidos no período de dezembro de 1995 a julho de 1997, nos Departamentos de Citopatologia, Anatomia Patológica e Cirurgia da Santa Casa de Belo Horizonte, Minas Gerais. No mesmo período foram realizados 256 PAAF de tireóide, sendo que somente 50 pacientes foram à cirurgia e puderam ter os diagnósticos citológicos comparados aos histológicos. O grupo estudado consistiu em 40 mulheres e 10 homens, com idades variando entre 10 e 79 anos, sendo a maior incidência observada nas 4ª e 5ª décadas. Baseando-se na comparação dos diagnósticos, os autores obtiveram as taxas de sensibilidade (80%), especificidade (100%), valor preditivo positivo (100%), valor preditivo negativo (89,5%) e acurácia (92,6%). De acordo com estes resultados, pôde-se concluir que a PAAF é um método seguro, eficiente e confiável no diagnóstico dos nódulos tireoidianos.

The Evaluation of Malignancy Rates of Nondiagnostic Cases in Thyroid Fine-Needle Aspirations

Aim: In this study, it was aimed to investigate the malignancy rates of nondiagnostic (ND) thyroid fine-needle aspiration cytology (FNAC) material by evaluating either the result of the second FNAC or resection/biopsy materials.Method: Among the 1165 thyroid FNAC cases evaluated in the Pathology Department of Başakşehir Çam and Sakura City Hospital within 9 months (October 2020-June 2021), 102 cases (8,7%) diagnosed with ND were included in the study. At the end of the 6-15 months follow-up period after the diagnosis of ND, the results of the second FNAC or resection (thyroidectomy, lobectomy)/biopsy of the cases were evaluated. Diameter and sonographic features of thyroid nodules (solid, cystic, mixed) were also noted.Results: 49% of the cases (n:50) had a second FNAC. Resection/biopsy was performed in only 12 (11,8%) cases. Of these 62 cases, 39 were diagnosed by second FNAC and 7 by resection/biopsy as benign (74,1%), and 5 cases were diagnosed as malignant by resection/biopsy. 7 cases were diagnosed as nondiagnostic again after the second FNAC. Final diagnosis (by resection) of the case whose second FNAC result was reported as suspicious for malignancy was papillary microcarcinoma. This case was included in the group ‘diagnosed as malignant only by resection/biopsy. In other words, malignancy was detected in 5 of 62 patients who underwent a second FNAC or resection/biopsy. The risk of malignancy was found to be 8% in the patient population included in the study with the diagnosis of ND.Conclusion: A low rate of NE results were found in this ultrasound-guided thyroid series (8,7%). After the second FNAC or resection, malignancy rates was found to be 8%. Although this result is compatible with the results of some studies, it is considerably lower than others. It would be appropriate to follow up on ND nodules with their clinical/sonographic features. Additional studies with large series will be more helpful in determining the malignancy rates of the ND group.

An alternative method for smear preparation of fine-needle aspiration cytology of cystic thyroid lesions: Evaluation of sample adequacy

BACKGROUND

Cystic thyroid lesions represent one of the most common causes of unsatisfactory fine-needle aspiration sampling. Thus, it is important to access the maximum number of follicular cells from cystic fluid in order to reduce unsatisfactory rates. We compared the traditional method of smearing with an alternative one.

METHODS

For each thyroid nodule, two smears were collected. Each smear was prepared using a distinct approach: either using the traditional technique or the alternative. Clinical data were taken from cytopathological request forms. The cytological aspects of the smears (eg, adequacy and number of cells) were observed during microscopy analysis. No cases were found to be suspicious for malignancy during ultrasound analysis (categories TR1 or TR2 according to ACR TI-RADS).

RESULTS

Thirty-five cases were analyzed. For smears prepared using both the traditional and the alternative techniques, 20 and 4 cases, respectively, were unsatisfactory. In the 20 unsatisfactory traditional smear cases, 9 (45%) showed enough cells for diagnosis in cytospin and/or cell block samples; the four unsatisfactory alternative method cases showed the same. There was a statistical difference between the two methods of collecting a smear concerning sample adequacy (P < .001), but there was no statistical difference regarding the cellularity (P = .842).

CONCLUSION

In our data, the alternative method of using only one slide and the needle tip had higher rates of adequate sampling. Since it is cost effective and does not change the cytological analysis, this proposed alternative method can be useful in cases of cystic thyroid lesions.

Determining whether surgeons perform thyroid fine-needle aspiration as well as radiologists: an analysis of the adequacy and efficiency of ultrasound-guided fine-needle aspiration performed by newly trained head and neck surgeons and radiologists

Background

Ultrasound-guided fine-needle aspiration (FNA) cytology is a crucial diagnostic technique used to assess thyroid nodules. In the past, ultrasound-guided FNA was performed mainly by radiologists. However, many surgeons are increasingly being trained for this procedure now. In this study, we aimed to compare the adequacy and efficiency of ultrasound-guided FNA performed by newly trained head and neck surgeons with experienced radiologists in a single institution. We also assessed the malignancy rates in nondiagnostic nodules and the differences between benign and malignant nodules.

Methods

This is a retrospective study. The data from patients who underwent ultrasound-guided FNA performed by surgeons or radiologists in two consecutive years were collected. Medical records, cytology results, and surgical pathology results were analyzed.

Results

During the study period, a total of 2,405 ultrasound-guided FNAs were performed on 2,163 patients. The head and neck surgeons and radiologists performed 1,132 and 1,273 ultrasound-guided FNA procedures, respectively. The nondiagnostic rate was 14.49% for surgeons and 15.40% for radiologists (P=0.533). There were no differences in patient age, gender, nodule size, and other sonographic characteristics between the groups of patients who were treated by radiologists versus surgeons. The median waiting time from biopsy appointment to performing ultrasound-guided FNA was 0 days for head and neck surgeons, and 6 days for radiologists (P<0.001). Of the 40 patients who had a repeat FNA or surgery, 19 (47.50%) had a malignancy. Preoperative information about age, gender, operator, and characteristics of nodules did not predict the outcome of nodules with Bethesda category I.

Conclusions

The adequacy of ultrasound-guided FNAs performed by head and neck surgeons is similar to that of skilled radiologists, while surgeons are more efficient than radiologists. Nondiagnostic FNA reports should not be considered benign, and repeat FNA or selective surgical treatment is recommended.

Risk of malignancy and clinical outcomes of cyst fluid only nodules in the thyroid based on ultrasound and aspiration cytology

BACKGROUND

The number of extensive studies focusing on cyst fluid only (CFO) thyroid nodules is limited, and the risk of malignancy (ROM) in CFO nodules has not been well-established. Thus, the purpose of this study was to investigate CFO nodules using cytology and ultrasound. In addition, we sought to define the ROM and determine the recommended clinical management of CFO nodules.

METHODS

We retrospectively reviewed cytological preparations of 678 nodules that were originally identified as CFO nodules, including conventional specimens in 209 nodules, liquid based cytology (LBC) specimens in 221 nodules, and both conventional and LBC specimens in 248 nodules. Ultrasound reports with representative photographs were also reviewed.

RESULTS

Of the 678 CFO nodules, 214 (31.6%) were reclassified into other categories, including non-diagnostic/unsatisfactory (ND/UNS) except for CFO (n = 15), benign (n = 198), and malignant (n = 1). Conventional preparations (33.5%) were more frequently reclassified than LBC preparations (13.6%; P < .0001). Re-aspiration for diagnosis was performed for only one calcified nodule. The rates of surgical resection and malignancy were 3.0% and 0.2%, respectively. Based on American Thyroid Association guidelines and the Kuma Hospital ultrasound classification, worrisome sonographic features were identified in 5.8% and 0% of CFO nodules, respectively.

CONCLUSION

We propose that CFO nodules should be classified as separate from ND/UNS nodules; they should be categorized as a subtype of benign nodules. However, it is essential that fine-needle aspiration cytology be performed under ultrasound-guided real-time visualization of needle placement in the target nodule in all cases.

Usefulness of Ultrasound-Guided Fine-Needle Aspiration Cytology in the Diagnosis of Non-Palpable Small Thyroid Nodules

Aims and background

Diverse and contradictory approaches have been suggested for the management of non-palpable thyroid nodules. The aim of our study was to evaluate the indications and limits of ultrasound-guided fine-needle aspiration cytology (US-FNAC) in non-palpable infracentimetric thyroid nodules.

Methods and study design

From September 2003 to December 2004 we observed 325 patients with non-palpable thyroid nodules. We divided our series into three groups according to the diameter of the lesion in order to verify the effectiveness of US-FNAC for lesions of less than 1 cm.

Results

We assessed the cases with satisfactory and unsatisfactory results in the three groups into which the sample was divided (4 mm to 1 cm; 10.1 mm to 15 mm, and 15.1 mm to 25.5 mm). Our statistical analysis by means of the z-test showed there was no significant (5%) difference in the percentage distribution of the unsatisfactory results in the three groups.

Conclusions

Fine-needle cytology appears to be a useful diagnostic tool also for nodules of less than one cm because the percentage of unsatisfactory results is not related to the size of the nodule.

Reappraisal of "cyst fluid only" on thyroid fine-needle aspiration cytology

According to the Bethesda System for Reporting Thyroid Cytopathology (BSRTC), cyst fluid only (CFO) cases are classified in the non-diagnostic category. To date, no large study focusing on CFO has been conducted. To reassess the diagnostic significance of CFO, we compared CFO nodules with non-diagnostic nodules excluding CFO (ND-other). We reviewed the conventional thyroid smears of 715 CFO and 766 ND-other nodules. We compared the timing of and findings at re-aspiration, the histology of resected specimens, and the proportion of malignant nodules between the two groups. Re-aspiration was performed in 9.0% of CFO and 23.8% of ND-other cases. In 12.5% of CFO and 49.4% of ND-other cases, the interval between the first and second aspirations was <3 months. Despite this, there were no cases in which cytological interpretation was complicated by the first aspiration. Overall, 77 CFO nodules (10.8%) were surgically resected; 14 were malignant. In all cases in which re-aspiration cytology revealed malignancy, the initial ultrasound interpretation was a high or intermediate suspicion pattern. The proportion of malignancies subsequently diagnosed in nodules initially classified as CFO and ND-other was 2.0% and 5.6%, respectively (p<0.01). As CFO and ND-other thyroid nodules have different clinical management and malignancy rates, we would like to assert that CFO and ND-other nodules should be separated, and that the former should be considered diagnostic. In terms of clinical management, we recommend that only CFO cases with concerning features on ultrasound undergo re-aspiration.

A Different Perspective on Evaluating the Malignancy Rate of the Non-Diagnostic Category of the Bethesda System for Reporting Thyroid Cytopathology: A Single Institute Experience and Review of the Literature

Objective

To determine the malignancy rate in the non-diagnostic (ND) category of the Bethesda System for Reporting Thyroid Cytopathology (BSRTC) based on a different approach in relation to histopathology diagnoses.

Study Design

All ND fine needle aspirations (FNAs) that were performed under ultrasound guidance by an interventional radiologist with rapid on-site evaluation were included in the study. Slides were reevaluated to identify the cause of inadequacy as “qualitative” or “quantitative.” The malignancy rate of the ND category was assessed. Nodule/patient characteristics were compared between benign and malignant cases within the study cohort.

Results

The study cohort consisted of 192 ND aspirations. Overall there were 156 (81.3%) women and 36 (18.7%) men with a mean age of 50.6 years (range 24–82 years). The malignancy rate was 4.7%. None of the nodules (size, consistency, and number) or patient characteristics (gender and age) were found to be predictive of malignancy.

Conclusion

The malignancy rate of the ND category was high when compared to BSRTC predictions, but at the low end of the reported malignancy rates in the literature. Our results revealed that cyto-histopathologic correlation and method of malignancy rate estimation could have an effect on a wide range of reported malignancy rates. Furthermore, patient/nodule dependent factors were not statistically found to be predictive of malignancy.

Thyroid nodules with nondiagnostic results on repeat fine-needle aspiration biopsy: which nodules should be considered for repeat biopsy or surgery rather than follow-up?

Purpose:

The goal of this study was to assess the clinicopathologic and ultrasonographic features of thyroid nodules with nondiagnostic results on repeat ultrasonography (US)-guided fineneedle aspiration biopsy (FNAB) according to size and the number of suspicious findings and to determine the proper management of nodules with consecutive nondiagnostic results.

Methods:

This retrospective study included 297 nodules with nondiagnostic results on repeat FNAB that were evaluated by US over the course of at least 12 months of follow-up, a follow-up biopsy, or an operation. We compared clinical and US variables between benign and malignant nodules in thyroid nodules with repeat nondiagnostic results.

Results:

The comparison of benign and malignant nodules with repeat nondiagnostic results revealed that age, marked hypoechogenicity, irregular or microlobulated margins, microcalcifications, and nonparallel shape were significantly associated with malignancy. Multivariate logistic regression analysis in malignant nodules revealed that microcalcifications and irregular or microlobulated margins were independently associated with malignancy. Among them, only irregular or microlobulated margins were independently significant as a predictor of malignancy in repeatedly nondiagnostic nodules measuring >10 mm. Using receiver operating characteristic analysis, the best cutoff value for the “number of suspicious findings” between benign and malignant nodules was three in nodules of all sizes, three in nodules measuring ≤10 mm, and two in nodules measuring >10 mm.

Conclusion:

Irregular or microlobulated margins may be the most frequent US features in repeatedly nondiagnostic nodules >10 mm. The presence of “two or more suspicious findings” can be used as the cutoff for distinguishing benign and malignant nodules.

The diagnostic accuracy of ultrasound-guided fine-needle aspiration biopsy for thyroid nodules three centimeters or larger in size

BACKGROUND AND PURPOSE

Whether under ultrasonography (US) guidance or not, fine-needle aspiration biopsy (FNAB) has some limitations, particularly in larger nodules. In this study, we aimed to evaluate the diagnostic value of US-guided fine-needle aspiration biopsy (US-FNAB) in thyroid nodules equal to or larger than 3 cm.

MATERIALS AND METHODS

Data of 267 patients operated for nodular goiter in the period of January 2006 and March 2012 were reviewed retrospectively. The study group (40 males, 104 females; mean age 42.3 ± 12.3, between 17 and 71) consisted of patients with nodules with a diameter of 3 cm or larger. Patients with nodules less than 3 cm in diameter were considered as the control group (27 males, 96 females; mean age 44.4 ± 11.9, between 18 and 71).

RESULTS

For nodules smaller than 3 cm, US-FNAB had an accuracy rate of 60% and a false negativity rate of 21.9%. In nodules equal to or larger than 3 cm, the accuracy rate of US-FNAB was 80%, with a false negativity rate of 6.7%. Malignancy was observed in 16% of the study group and 42.3% of the control group.

CONCLUSION

This study showed that increased nodule diameter is not associated with limitations in the diagnostic value of US-FNAB. We also found that the malignancy rate was smaller for larger nodules. This finding reflects the importance of accurate and rational diagnostic work-up and clinical management for detecting malignancy and surgical decision-making.

Do repeatedly nondiagnostic fine needle aspirations of thyroid nodules predict malignancy risk?

Fine needle aspiration biopsy (FNAB) is a common, minimally invasive, cost-effective, and rapid method to manage thyroid nodules, but nondiagnostic FNAB (ND-FNAB) is still a common problem due to high prevalence (2%-20%). Our purpose in this study is to investigate risk of malignancy of repeating ND-FNABs and correlation between clinical and ultrasound findings. Our cohort study included 75 patients who had 2 or more times ND-FNABs and, finally, undergone surgical resection. We evaluated demographic, clinical, ultasonographic, and pathologic features. Fifty-seven patients were female, and 22 patients were male. Seventy-five patients' histopathologic results were 76% (n=57) benign and 24% (n=18) malignant. Of malignant nodules, 94.4% (n=17) were papillary carcinoma, whereas 5.6% (n=1) were follicular carcinoma. We did not find any predictive factor for malignancy and any differences associated with clinical and ultrasonographic features between benign and malignant nodules. Reaspiration followed by surgery for appropriate patients is recommended.

Ultrasound-based diagnosis for solid thyroid nodules with the largest diameter <5 mm

This study was aimed at assessing the efficacy of using an ultrasound (US)-based classification system to diagnose solid thyroid nodules with the largest diameter <5 mm (i.e., small solid nodules). For 406 small solid nodules in 365 patients who underwent thyroid US and US-guided fine-needle aspiration, each thyroid nodule was prospectively classified into one of five diagnostic categories: benign, probably benign, borderline, possibly malignant and malignant. Of 406 nodules, 145 were surgically removed: 95 papillary thyroid carcinomas, 1 follicular thyroid carcinoma, 1 poorly differentiated carcinoma, 3 pseudonodules related to thyroiditis and 45 nodular hyperplasias. On the basis of the histopathologic results, the diagnostic accuracies of US diagnosis and cytologic diagnosis were similar, but the sensitivity of US diagnosis was higher than that of cytologic diagnosis, and the specificity and positive predictive values of US diagnosis were lower those of cytologic diagnosis. An US-based classification system may be helpful for the diagnosis and management of small solid nodules.

Malignancy risk analysis in patients with inadequate fine needle aspiration cytology (FNAC) of the thyroid

BACKGROUND

Thyroid fine needle aspiration cytology (FNAC) is the standard diagnostic modality for thyroid nodules. However, it has limitations among which is the incidence of non-diagnostic results (Thy1). Management of cases with repeatedly non-diagnostic FNAC ranges from simple observation to surgical intervention. We aim to evaluate the incidence of malignancy in non-diagnostic FNAC, and the success rate of repeated FNAC. We also aim to evaluate risk factors for malignancy in patients with non-diagnostic FNAC.

MATERIALS AND METHODS

Retrospective analyses of consecutive cases with thyroid non diagnostic FNAC results were included.

RESULTS

Out of total 1657 thyroid FNAC done during the study period, there were 264 (15.9%) non-diagnostic FNAC on the first attempt. On repeating those, the rate of a non-diagnostic result on second FNAC was 61.8% and on third FNAC was 47.2%. The overall malignancy rate in Thy1 FNAC was 4.5% (42% papillary, 42% follicular and 8% anaplastic), and the yield of malignancy decreased considerably with successive non-diagnostic FNAC. Ultrasound guidance by an experienced head neck radiologist produced the lowest non-diagnostic rate (38%) on repetition compared to US guidance by a generalist radiologist (65%) and by non US guidance (90%).

CONCLUSIONS

There is a low risk of malignancy in patients with a non-diagnostic FNAC result, commensurate to the risk of any nodule. The yield of malignancy decreased considerably with successive non-diagnostic FNAC.

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

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

Ultrasound-based diagnostic classification for solid and partially cystic thyroid nodules

BACKGROUND AND PURPOSE

The ability of US to differentiate benign thyroid nodules from malignant ones is still a matter of debate. The aim of this study was to assess the diagnostic efficacy of a US-based classification system for solid and PCTNs through a prospectively designed study.

MATERIALS AND METHODS

We studied 1289 thyroid nodules in 1036 patients who underwent thyroid US, US-FNA, and thyroid surgery. Each thyroid nodule was prospectively classified into 1 of 5 diagnostic categories following real-time US examination: benign, probably benign, borderline, possibly malignant, and malignant. Solid nodules were classified by using all 5 categories, and PCTNs were classified by all except the borderline category. We calculated the diagnostic efficacy of thyroid US by comparing US diagnoses with histopathologic results of surgically resected thyroid nodules.

RESULTS

One thousand fifty-five solid nodules and 234 PCTNs were prospectively classified as benign (n = 435 and 179), probably benign (n = 213 and 25), borderline (n = 94 and 0), possibly malignant (n = 115 and 15), and malignant (n = 198 and 15), respectively. Of these 1289 nodules, 505 were surgically resected and confirmed by pathology (191 benign and 314 malignant nodules); there were 44 resected solid nodules with a borderline category. For solid nodules and PCTNs, the sensitivity, specificity, positive and negative predictive values, and accuracy of US diagnosis were 86.1 and 66.7, 90.0 and 88.9, 94.3 and 75.0, 77.3 and 84.2, and 87.5% and 81.5%, respectively, based on 505 surgical specimens and excluding the 42 solid borderline nodules.

CONCLUSIONS

Our US-based classification system can provide helpful guidance for the management of thyroid nodules.

The diagnostic accuracy of ultrasound-guided fine-needle aspiration biopsy and the sonographic differences between benign and malignant thyroid nodules 3 cm or larger

BACKGROUND

Although fine-needle aspiration biopsy (FNAB) is considered the standard for preoperative evaluation of thyroid nodules, the value of this has been questioned for large thyroid nodules. Here, we evaluated the diagnostic accuracy of ultrasound-guided FNAB (US-FNAB) for thyroid nodules that were 3 cm or larger as well as the sonographic differences between benign and malignant nodules in this size group.

MATERIALS AND METHODS

There were 661 thyroid masses equal to or larger than 3 cm who underwent US-FNAB from February 2002 to December 2006 and were included in this study. The cytology and surgical pathology readings in these patients were reviewed along with the ultrasonography features, the last from the retrospective review by one radiologist. Histopathology was used to calculate accuracy parameters for the US-FNAB cytology readings. In addition, the likely diagnoses for patients with a benign cytology reading were ascertained.

RESULTS

Thyroid surgery was performed for 206 of the 661 nodules in the same number of patients (31.2%). All subjects who had inadequate, indeterminate, or suspicious for malignancy cytology readings had thyroid surgery. All of the patients who did not have thyroid surgery were considered likely to have benign disease because of their initial cytology reading and follow-up, and finally, 587 (88.8%) were benign and 74 (11.2%) were malignant. When considering malignant, suspicious for malignancy, and indeterminate cytology readings as positive and benign cytology as negative, the sensitivity was 96.7%, specificity 85.9%, positive predictive value 76.6%, negative predictive value 98.2%, and accuracy 89.4%. Ultrasonography features of malignancy were more prevalent in thyroid nodules that were malignant compared with those that were benign or considered likely to be benign (70.3% vs. 1.2%, p < 0.001), and ultrasonography features of a benign nodule were more prevalent in thyroid nodules that were benign or considered likely to be benign than those that were malignant (94.9% vs. 29.7%, p < 0.001).

CONCLUSION

In this study, US-FNAB appeared to be a relatively accurate method to evaluate thyroid nodules larger than 3 cm, with false-negative rates of about 2%. Much larger series would be required to determine its utility in this setting.

The impact of using defined criteria for adequacy of fine needle aspiration cytology of the thyroid in routine practice

The fine needle aspiration cytology (FNAC) of the thyroid is the predominant method of preoperative tissue diagnosis of thyroid lesions. The routine use of FNAC has reduced the rate of unnecessary surgery for thyroid nodules. However, there are overlaps in the existing criteria for defining adequacy in thyroid aspirates. In this study, we aimed to explore the reasons for high percentage of inadequate thyroid FNAC samples and to reevaluate those samples by applying clearly defined criteria suggested in the literature to reduce the proportion of inadequate aspirates. The results of 550 smears reported as inadequate FNAC samples are presented over a period of 15 years extending from 1986 to 2000 (18.8%). For the purpose of the study, only those patients with subsequent histological or cytological analysis were included (279). The original FNA samples were reviewed by two cytopathologists, unaware of the subsequent repeat cytology or histology results. Specific criteria for adequacy of specimens were used which include the presence of six or more groups of follicular cells, each having more than 10 discernable viable cells or 60 isolated viable follicular cells. Out of 279, 82 (29%) FNAC samples originally reported as inadequate met our criteria and were considered adequate on review. Of these 82 cases, subsequent surgical excision showed malignancy in 5 cases (6%), adenoma in 7 (9%), and benign hyperplasia and thyroiditis in 70 cases (85%). In addition, 16 (5%) cases were classified as cysts. The slide preparation error was noticed in 26 (14%) and the sampling error was observed in 160 (86%) cases. The use of well-defined criteria for adequacy is helpful because it improves the diagnostic efficiency of thyroid FNA and avoids unnecessary surgery for benign nonneoplastic thyroid lesions. However, since application of these criteria has also resulted in an increase in the false-negative diagnoses, they should be applied in the multidisciplinary context.

Factors affecting inadequate sampling of ultrasound-guided fine-needle aspiration biopsy of thyroid nodules

PURPOSE

The aim of this study was to evaluate the overall ultrasonographic features and clinical factors that contribute to inadequate sampling in ultrasound-guided fine-needle aspiration biopsy (US-FNAB) of thyroid nodules.

MATERIALS AND METHODS

From April 2008 to December 2008, 4077 US-FNABs in 3767 consecutive patients were reviewed. We evaluated the clinical, ultrasound and pathological features of patients and analysed the association between these features and inadequate samples. We also compared inadequate sample rates according to the experience of the performing doctor.

RESULTS

The inadequate sample rate was 16·1% (654/4077). Univariate analysis revealed an association between inadequate samples and cyst dominancy, macrocalcification and benign pathology of the nodule. The inadequate sample rate was also higher in the inexperienced group than in the experienced group. In multivariate analysis, cyst dominancy and macrocalcification of a nodule were significantly associated with inadequate samples in the experienced group.

CONCLUSION

Cyst dominancy and macrocalcifications in thyroid nodules, inexperience of the performing doctor and benign pathology were factors associated with high inadequate sample rates of US-FNAB in thyroid nodules.

Fine-needle aspiration biopsy of thyroid nodules: comparison of diagnostic performance of experienced and inexperienced physicians

OBJECTIVE

To determine whether a difference exists in terms of obtaining adequate cytologic samples from ultrasound-guided fine-needle aspiration cytology (US-FNAC) between experienced and inexperienced physicians in a tertiary referral center.

METHODS

In a prospective design, all patients with thyroid nodules of at least 10 mm in diameter were referred for US-FNAC tissue sampling as a part of their diagnostic work-up. Between May 2006 and September 2009, 997 euthyroid patients with 1,320 thyroid nodules were referred for US-FNAC by the attending endocrinologist (experienced physician) or 1 of 2 endocrinology fellows (inexperienced physicians).

RESULTS

Of the 1,320 nodules, 713 biopsy specimens were obtained by the experienced physician and 607 were obtained by the inexperienced physicians. Nodule size was significantly larger in the endocrinologist's group of patients than in the fellows' group of patients (17 mm versus 14 mm, respectively; P<.001). The inadequacy rate of the US-FNAC procedures performed by the experienced physician (22 of 713 thyroid nodules or 3.1%) was significantly lower than for those performed by the inexperienced physicians (102 of 607 thyroid nodules or 16.8%) (P<.001).

CONCLUSION

We conclude that, with increasing operator experience, the number of inadequate cytologic specimens generated by US-FNAC procedures is substantially reduced. This limits both direct and indirect costs and also minimizes the risks of possibly unnecessary surgical procedures.

Inadequate cytology in thyroid nodules: should we repeat aspiration or follow-up?

BACKGROUND

To evaluate how to correctly manage thyroid nodules showing inadequate cytology after ultrasound (US)-guided fine-needle aspiration biopsy (US-FNAB).

MATERIALS AND METHODS

A total of 393 thyroid nodules with inadequate cytology in 351 patients (M:F = 40:311, mean age: 49.3 years) with surgery or follow-up US-FNAB for at least 1 year were included in this study. Among them, 293 (74.6%) were benign and 100 (25.4%) were malignant on final reference results. Clinical characteristics and US features were reviewed and compared.

RESULTS

Malignancy rates (39.5%) of nodules having suspicious US feature were significantly higher than those (10.9%) of nodules without any suspicious US feature (P < .001). Malignancy rates of solid nodules, mainly solid nodules, and mainly cystic nodules were 29.2, 16.7, and 9.5%, respectively, with significant differences (P = .016). Malignancy rates of nodules assessed as suspicious malignant to probably benign in composition are: 39.1-12.8% (P < .001) in solid nodules, 42.1-9.2% (P = .001) in mainly solid nodules, and 50.0-5.3% (P = .04) in mainly cystic nodules.

CONCLUSIONS

In nodules with inadequate cytology, follow-up US can be considered over repeat aspiration if there are no suspicious US features present, especially in mainly cystic nodules.

Thyroid nodules; interpretation and importance of fine-needle aspiration (FNA) for the clinician - practical considerations

Thyroid nodules are very common lesions. Despite that the great majority is benign, in a significant percentage of them there is an underlying malignancy. Malignant thyroid nodules should be managed surgically, while the more common benign thyroid nodules may be managed conservatively. A systemic and careful diagnostic evaluation is needed to recognize nodules (overtly malignant or with malignant potential), and to avoid unnecessary surgery in a large percentage of patients with benign disease. Fine-needle aspiration (FNA) has a central role in the diagnostic investigation of the patient with thyroid nodules. FNA is a safe, useful, and cost-effective procedure. To increase accuracy, FNA can be performed under ultrasonographic guidance (if needed). Its results may be particularly helpful in determining the indication for surgery. In contrast, the role of FNA in selecting the extent of surgery is limited today. This is due to the fact that during the last decade there is a clear trend toward radical surgical management of thyroid nodular disease (both benign and malignant) by total/near-total thyroidectomy.

Does a repeated benign aspirate change the risk of malignancy after an initial atypical thyroid fine-needle aspiration?

Repeated fine-needle aspiration of the thyroid is sometimes recommended after an atypical diagnosis. However, histologic follow-up for patients with a benign second aspirate is limited. I reviewed the results of all thyroid aspirations with repeated aspirations and surgical resection for the last 13 years at Baptist Hospital, Miami, FL, and Homestead Hospital, Homestead, FL, and combined these with the results of intraoperative cytology and the literature. During the period, a total of 7,089 cases were aspirated and 1,331 resections were performed. There were 6 (1.7%) of 361 false-negative cases. Relevant intraoperative cytology was available for 24 cases. The order of the diagnoses (benign then atypical, atypical then benign) did not significantly affect the risk of malignancy (15% and 9%; P = .30). Patients with an atypical and benign diagnosis had a risk of malignancy (15%) higher than a single negative aspirate (3%; P < .001) and lower than that of patients with a single atypical diagnosis (27%; P < .001). Repeated aspirates are not independent events. Patients with a benign diagnosis after an atypical diagnosis have a risk of malignancy between the risks of a single benign or atypical diagnosis. Cytologists should strive to better communicate this risk.

Usefulness of ultrasound-guided fine-needle aspiration cytology in the diagnosis of non-palpable small thyroid nodules: our growing experience

AIMS AND BACKGROUND

Contradictory approaches have been suggested for the management of non-palpable thyroid nodules. The aim of our study is to evaluate indications and limits of ultrasound-guided fine-needle aspiration cytology (US-FNAC) in the management of non-palpable infracentimetric thyroid nodules.

METHODS AND STUDY DESIGN

From September 2003 to June 2007 we studied 1043 patients with non-palpable thyroid nodules. We divided our series into three groups according to the diameter of the lesion in order to verify the effectiveness of US-FNAC for lesions <1 cm.

RESULTS

We assessed the cases with satisfactory and unsatisfactory results in the 3 groups into which the sample was divided. Our statistical analysis using the z-test showed there was no significant (p=0.05) difference in the percentage distribution of the unsatisfactory results in the 3 groups.

CONCLUSIONS

FNAC appears to be a useful diagnostic tool also for nodules <1 cm because the percentage of unsatisfactory results is not related to the size of the nodule.

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.

Thyroid disorders: evaluation and management of thyroid nodules

Although thyroid nodules are a common clinical entity, few (5% to 10%) are malignant and require surgical treatment. Most nodules are discovered incidentally in patients undergoing surveillance for medical reasons unrelated to thyroid disorders. Therefore, a systematic approach to their evaluation is important to avoid unnecessary surgery. High-resolution ultrasonography and fine-needle aspiration have resulted in substantial improvements in diagnostic accuracy, cost reductions, and higher malignancy yield at the time of surgery. In this article, the authors present practical guidelines and a suggested management strategy for the effective diagnosis and management of incidentally discovered thyroid nodules.

Nondiagnostic thyroid fine-needle aspiration biopsies are no longer a dilemma

BACKGROUND

Nondiagnostic fine-needle aspiration biopsy (ND-FNAB) of the thyroid leads to unnecessary thyroidectomy. The aims of this study were as follows: (1) to determine the risk of malignancy in ND-FNABs, and (2) to evaluate factors that may identify patients at risk for a ND-FNAB.

METHODS

A total of 241 patients who underwent FNAB and thyroidectomy were evaluated for factors associated with a ND-FNAB.

RESULTS

A total of 215 women and 26 men underwent FNAB and thyroidectomy. ND-FNAs occurred in 51 of 241 (21%) patients. Ultrasound guidance did not reduce the likelihood of a ND biopsy. Patients with nodules greater than 3 cm had more ND-FNAs. Twenty-one of 51 with a ND biopsy underwent a repeat FNAB. Repeat FNAB was ND in 29% of patients. There was malignant disease in 7 of 51 (14%) with a ND-FNAB. Patient age, sex, thyroid function, gland size, multiple nodules, and final pathology were not related to a ND-FNAB (P > .05).

CONCLUSIONS

Most patients with a ND-FNAB have benign disease and low-risk patients with a ND-FNAB on repeat FNA warrant a more conservative approach.

Thyroid nodules: clinical importance, assessment, and treatment

In the general population, thyroid nodules are found in 5% by palpation and in 50% by ultrasonography (US). Initial evaluation of nodules should include serum thyroid-stimulating hormone measurement, fine-needle aspiration (FNA) biopsy, and US. Thyroid micronodules are being detected with increasing frequency and are currently evaluated by US-FNA. Routine measurement of serum calcitonin and thyroglobulin and FNA rebiopsy are not recommended. Cytologically benign thyroid nodules should be followed rather than treated. Novel treatment options including iodine 131, percutaneous ethanol injection, and percutaneous laser thermal ablation have specific indications, advantages, and adverse effects.

American Association of Clinical Endocrinologists and Associazione Medici Endocrinologi medical guidelines for clinical practice for the diagnosis and management of thyroid nodules

Thyroid nodules are common and are frequently benign. Current data suggest that the prevalence of palpable thyroid nodules is 3% to 7% in North America; the prevalence is as high as 50% based on ultrasonography (US) or autopsy data. The introduction of sensitive thyrotropin (thyroid-stimulating hormone or TSH) assays, the widespread application of fine-needle aspiration (FNA) biopsy, and the availability of high-resolution US have substantially improved the management of thyroid nodules. This document was prepared as a collaborative effort between the American Association of Clinical Endocrinologists (AACE) and the Associazione Medici Endocrinologi (AME). Most Task Force members are members of AACE. We have used the AACE protocol for clinical practice guidelines, with rating of available evidence, linking the guidelines to the strength of recommendations. Key observations include the following. Although most patients with thyroid nodules are asymptomatic, occasionally patients complain of dysphagia, dysphonia, pressure, pain, or symptoms of hyperthyroidism or hypothyroidism. Absence of symptoms does not rule out a malignant lesion; thus, it is important to review risk factors for malignant disease. Thyroid US should not be performed as a screening test. All patients with a palpable thyroid nodule, however, should undergo US examination. US-guided FNA (US-FNA) is recommended for nodules > or = 10 mm; US-FNA is suggested for nodules < 10 mm only if clinical information or US features are suspicious. Thyroid FNA is reliable and safe, and smears should be interpreted by an experienced pathologist. Patients with benign thyroid nodules should undergo follow-up, and malignant or suspicious nodules should be treated surgically. A radioisotope scan of the thyroid is useful if the TSH level is low or suppressed. Measurement of serum TSH is the best initial laboratory test of thyroid function and should be followed by measurement of free thyroxine if the TSH value is low and of thyroid peroxidase antibody if the TSH value is high. Percutaneous ethanol injection is useful in the treatment of cystic thyroid lesions; large,symptomatic goiters may be treated surgically or with radioiodine. Routine measurement of serum calcitonin is not recommended. Suggestions for thyroid nodule management during pregnancy are presented. We believe that these guidelines will be useful to clinical endocrinologists, endocrine surgeons, pediatricians, and internists whose practices include management of patients with thyroid disorders. These guidelines are thorough and practical, and they offer reasoned and balanced recommendations based on the best available evidence.

Management of nondiagnostic thyroid fine-needle aspiration biopsy: survey of endocrinologists

OBJECTIVE

To evaluate the approach of endocrinologists in the setting of nondiagnostic thyroid fine-needle aspiration (FNA) biopsies.

METHODS

In 2002, we surveyed physicians attending the national annual meetings of the American Association of Clinical Endocrinologists and the Endocrine Society of North America, using a 13-item questionnaire. The responses were tallied and analyzed.

RESULTS

Of the 143 respondents, 139 were endocrinologists, with a male:female ratio of 2.5:1. Most respondents were involved in a medical practice in North America, but Europe, Asia, New Zealand, and Australia were also represented. Of those performing thyroid FNA biopsy, 31% used thyroid ultrasound guidance. Among the survey respondents, 16%, 49%, 20%, and 15% performed less than 2, 2 to 5, 6 to 10, and more than 10 thyroid FNA biopsies per month, respectively. Among the respondents, 13.5%, 44%, 28.5%, 10%, and 4% had non-diagnostic rates of less than 5%, 5 to 10%, 11 to 20%, 21 to 30%, and more than 30%, respectively. The approach of the respondents to an initially nondiagnostic FNA was repeated FNA biopsy in 87%, observation in 7%, levothyroxine suppression in 4%, and thyroid scintigraphy in 2%. Respondents believed that the most cost-effective approach in a patient with nondiagnostic FNA was repeated biopsy (82%), monitoring the size of the thyroid nodule (17%), and surgical referral (<1%). No one was willing to repeat the thyroid biopsy more than three times.

CONCLUSION

On the basis of findings in our survey, most endocrinologists repeat thyroid FNA at least once when confronted with a nondiagnostic result. No published studies have demonstrated the cost-effectiveness of this approach versus proceeding to surgical intervention or observation. We hope that this survey will encourage further studies on this issue.

Punção aspirativa por agulha fina guiada por ultra-sonografia de nódulos tireoidianos: estudo de 63 casos

Neste trabalho foi revisada a técnica empregada na execução da punção aspirativa por agulha fina guiada por ultra-sonografia, e são descritos os seus benefícios no diagnóstico de nódulos tireoidianos. Foram realizadas punções aspirativas por agulha fina em 63 pacientes do Hospital Universitário Clementino Fraga Filho da Universidade Federal do Rio de Janeiro, encaminhados ao Serviço de Radiodiagnóstico, no período de agosto de 2001 a junho de 2002. Dos 63 pacientes estudados, 58 (92%) eram do sexo feminino e cinco (8%) eram do sexo masculino, com uma relação mulher/homem de cerca de 11:1. Trinta e um pacientes (49%) se situaram na quinta e sexta décadas de vida. Oitenta e nove por cento dos pacientes apresentaram-se com nódulos múltiplos ao exame ecográfico; apenas 11% dos pacientes tinham nódulo único. Em relação aos laudos citológicos dos nódulos puncionados, 47% foram benignos, 31%, suspeitos, 17%, inadequados e apenas 5%, malignos. Todos os nódulos malignos (três pacientes) tiveram o diagnóstico citológico de carcinoma papilífero. Dos nódulos benignos, 93% foram diagnosticados como hiperplasia nodular e apenas 7% tiveram diagnóstico de tireoidite. Dos laudos considerados inadequados, 70% foram considerados hemorrágicos, sendo 30% considerados hipocelulares. Os dados encontrados no nosso trabalho estiveram de acordo com os encontrados na literatura médica.

Fine-Needle Aspiration of Thyroid Nodules: Past, Present, and Future

OBJECTIVE

To present a review of the traditional and more recent techniques and applications of thyroid fine-needle aspiration biopsy.

METHODS

We describe the cytologic features and differential diagnoses of various thyroid lesions, outline recommendations for diagnostic categories, and discuss new techniques that have shown some promise in the diagnosis of thyroid nodule fine-needle aspiration specimens.

RESULTS

Fine-needle aspiration biopsy of the thyroid has proved to be an excellent diagnostic tool in the initial management of thyroid nodules. Numerous studies have shown its high sensitivity and specificity in diagnosing malignant tumors of the thyroid, especially papillary thyroid carcinoma. As with other diagnostic tests, however, its effectiveness is highly dependent on the expertise of the operator performing the procedure and the adequacy of the specimen for interpretation of the cytomorphologic features. On-site evaluation of thyroid specimens promotes adequate specimen sampling and reduces the incidence of nondiagnostic specimens. Diagnostic reports on thyroid fine-needle aspiration should include patient demographics and pertinent clinical history, site and size of the thyroid nodule, mode of aspiration, number of needle passes, assessment of specimen adequacy, diagnosis, and recommendations. Although immunohistochemical and molecular markers have received considerable attention recently, additional studies are needed before they can be used to separate benign from malignant follicular thyroid lesions.

CONCLUSION

Overall, fine-needle aspiration biopsy of thyroid nodules has proved to be sensitive, specific, and well accepted by patients because of minimal discomfort and complications.

Role of repeat fine-needle aspiration biopsy (FNAB) in the management of thyroid nodules

The purpose of the present study was to determine the role of repeat fine-needle aspiration biopsy (FNAB) in the evaluation of thyroid nodules initially classified as "nondiagnostic" due to limited cellularity or as "indeterminate for neoplasm." We reviewed a cohort of 431 patients (352 females, 79 males; average age 50 yr); 237 patients were classified as "nondiagnostic" due to limited cellularity and 194 as "indeterminate for neoplasm" over a 3-yr period (1999-2002). Repeat FNAB under ultrasound guidance was performed in 226 patients (226/431, 52%); surgical pathology results were available in 101 patients. Repeat FNAB diagnoses were: benign 70 (31%), follicular/Hürthle cell neoplasm 62 (27%), suspicious for papillary carcinoma 25 (12%), malignant 17 (7%), and nondiagnostic 52 (23%) cases. Surgical follow-up was available in 101 (45%) patients; malignancy was identified in 50 (49%) patients. The malignancy rate was 51% and 48% in cases in which initial FNAB was nondiagnostic and indeterminate for neoplasm, respectively. There were no false-positives and all malignant cases undergoing surgery were found to be malignant. This study demonstrates that repeat FNAB is warranted in patients with thyroid nodules diagnosed on initial FNAB as nondiagnostic and indeterminate for neoplasm since it can yield a definitive diagnosis in the majority of cases with an overall malignancy rate of 49%.

Analysis of inconclusive fine-needle aspiration of thyroid follicular lesions

To evaluate all inconclusive fine-needle aspiration biopsy (FNAB) specimens from thyroid follicular lesions with subsequent histologic diagnosis at St John Hospital and Medical Center, Detroit, MI. The criterion for specimen adequacy used in our institution was also reexamined to determine whether it was too stringent. We reviewed 45 inconclusive FNAB samples. Only cases that underwent surgical intervention were considered. Specimen adequacy was determined by the presence of at least 8-10 tissue fragments of well-preserved follicular epithelium on at least two slides; each tissue fragment should have a minimum of 8-10 cells. Different cytologic characteristics-cellularity, cellular architecture, nuclear pleomorphism, inclusion/grooves, chromatin, Hürthle cell change, lymphocytes, macrophages, colloid, and multinucleated giant cells-were scored and compared with final surgical diagnosis. The surgical procedure performed was also analyzed. Review of these 45 surgical specimens found 28 (62.2%) multinodular goiters, 14 (31.1%) nodular hyperplasias, 2 (4.4%) follicular adenomas, and one (2.2%) with invasive follicular carcinoma. Forty-three (95.6%) of these cases were female and 2 (4.4%) were male. Cytologic review showed 2 acellular samples, 10 cases containing macrophages only, 10 aspirates with macrophages and an inadequate number of follicular cells, and 23 specimens with an inadequate number of follicular cells. Twenty-three patients underwent total thyroidectomy; 20, lobectomy; and 2, isthumusectomy. Almost 98% of the patients with inconclusive FNAB had benign lesions. This finding encouraged us to continue using our criteria for adequacy because of the importance of a negative report. Patients in our series, who underwent thyroidectomy after an inconclusive or nondiagnostic aspirate, had a malignancy rate of 2.2%, which was no worse than patients with a benign preoperative diagnosis. A balanced approach with careful follow-up for nondiagnostic cytology is prudent.

Ultrasonography: is it useful in the diagnosis of cancer in thyroid nodules?

The role of ultrasonography (US) in the diagnosis of cancer in thyroid nodules is not well-established. The aim of the present study was to evaluate US performance in predicting cancer in thyroid nodules using a novel approach. Two hundred and eighty-nine patients with thyroid nodular disease were evaluated with clinical, biochemical and cytopathological examinations. Eighty patients with palpable solitary thyroid nodules or multinodular goiters who were to undergo surgery were included, and had a US exam performed by one of us. Some US characteristics of thyroid nodules were associated to cancer: absent halo, hypoechogenicity and microcalcifications, with sensitivity, respectively, of 56, 44 and 56%, and specificity of, respectively, 80, 83 and 94%. These findings were considered positive and were studied in two different combinations: simultaneous, when two or more were positive, and parallel, when any positive finding was present. When positive findings were studied simultaneously, sensitivity ranged 25 to 38% and specificity ranged 89 to 97%. Microcalcifications, associated or not to other findings, were highly specific for thyroid cancer, but they were only present in half of the malignancies. When positive findings were studied in parallel, sensitivity ranged 69 to 81% and specificity ranged 70 to 81%. The parallel combination of hypoechogenicity or microcalcifications or absent halo improved US sensitivity to 81% with an acceptable specificity (70%). This method is potentially useful to help us select patients for surgery when fine-needle aspiration biopsy is repetitively non-diagnostic or select for biopsy incidentally discovered non-palpable nodules.

Nondiagnostic thyroid fine-needle aspiration cytology: management dilemmas

Approximately 10% to 20% of thyroid biopsies by fine-needle aspiration (FNA) are nondiagnostic. The management of thyroid nodules in which FNA is nondiagnostic remains controversial because few studies have addressed this issue. We retrospectively reviewed the medical records of 153 patients with nondiagnostic FNAs of the thyroid performed in 1994. Sixty patients had reaspiration biopsies performed. Thirty-seven specimens (62%) were diagnostic and 23 (38%) remained nondiagnostic. Of the 27 patients who had a thyroid operation, 10 (37%) had a malignancy. Preoperative information about physical examination, ultrasound imaging, or nondiagnostic FNA did not predict outcome. Nondiagnostic FNAs of the thyroid may be associated with a high probability of thyroid malignancy. Nondiagnostic FNAs should not be considered benign. Reaspiration followed by selective surgical treatment is recommended.

Fine-needle aspiration of the thyroid: rate and causes of cytohistopathologic discordance

Fine-needle aspiration (FNA) of the thyroid gland is a widely utilized, sensitive, specific, and cost-effective method for the evaluation of thyroid nodules. The purpose of this study was to evaluate the accuracy of thyroid FNA and causes of cytohistological discordance in our institution. Six hundred twenty-five thyroid FNAs obtained from 503 females (mean age, 54) and 122 males (mean age, 51) in whom histopathologic follow-up material was available for review, were analyzed. FNAs were classified as: nondiagnostic, negative, intermediate, and positive for malignancy, and the histopathologic material was categorized as benign or malignant. The review revealed 93% sensitivity and 96% specificity for the FNA diagnoses. The FNA results were diagnostic in 87%, indeterminate in 6%, and nondiagnostic in 7% of the cases. Cytohistologic correlation was achieved in 88% of the cases. The false-negative rate was 4% and the false-positive rate was 8%. The most common pitfalls for false-negative diagnoses consisted of suboptimal material and underdiagnosis of papillary carcinoma due to cystic degeneration. The most common pitfall for false-positive cases was overdiagnosis of follicular neoplasms. Our study confirmed that FNA of thyroid nodules can be performed with high sensitivity and specificity by experienced clinicians or pathologists. The application of strict specimen adequacy rules for FNA interpretation is likely to decrease the rate of false-negative and false-positive diagnoses.

Ultrasound-guided fine-needle aspiration biopsy of the thyroid

BACKGROUND

We reviewed the Massachusetts General Hospital experience with ultrasound-guided fine-needle aspiration biopsies (FNABs) of the thyroid to determine the indications, rate of unsatisfactory smears, correlation with excisional biopsy results, and verification of efficient use of personnel time.

METHODS

All radiologically guided FNABs of the thyroid from January 1993 through June 1997 were reviewed. As a measure of efficient use of technologist time, a sample of times spent by the technologist during the procedure for 20 cases in 1993 and 1997 was compared with that of an equal number of random nonthyroid image guided FNABs.

RESULTS

Two hundred-ninety FNABs were identified in 251 patients, representing 12% of all thyroid FNABs and 11% of all radiologically guided FNABs. Indications in the 251 patients included multiple nodules (78), solitary nodules (61), complex nodules (39), prior failed FNAB (39), thyroid bed abnormalities post-thyroidectomy (21), difficult access (7), and investigation of recurrent tumor in residual thyroid lobe (6). Available records indicated 118 lesions were palpable and 45 were nonpalpable; the physical examination characteristics of the remainder (88) were not stated. Diagnoses included 44 unsatisfactory cases (15%), 103 macrofollicular lesions, 20 microfollicular lesions, 26 mixed macro/microfollicular lesions, 5 oxyphilic lesions, 1 trabecular pattern, 15 nonspecific follicular cell pattern, 9 follicular cell atypia, 30 cysts, 11 thyroiditis, 23 malignant tumors, and 3 other (1 parathyroid, 2 lymph node). Eighty-nine FNABs from 76 patients had subsequent surgical biopsy. Excisional biopsies in 14 unsatisfactory FNABs were benign. In the remaining 75 FNABs from 67 patients, 18 malignancies on FNAB were correctly diagnosed, but 3 other papillary carcinomas were only qualified as atypical follicular cells on cytology. No false-positive cases occurred. Of 15 macrofollicular lesions on cytology, 10 were adenomas on excision, only 2 of which were microfollicular adenomas, and 4 were adenomatous nodules. An aspirate of a parathyroid adenoma was misinterpreted as a macrofollicular lesion of the thyroid. Three microfollicular lesions on FNAB proved to be nodular hyperplasia on excision, and the other 11 were adenomas, 5 of them microfollicular. Average technologist time was significantly longer for thyroid FNABs than nonthyroid FNABs in 1993, but in the 1997 sample no significant difference was identified.

CONCLUSIONS

Radiologically guided FNAB of the thyroid is a clinically useful procedure with a high correlation between benign lesions not needing excision (macrofollicular), and lesions that need excision (microfollicular/oxyphilic cell or malignant). Technologist time needed for immediate evaluation tends to decrease with increasing operator experience. Cancer (Cancer Cytopathol)

Sensitivity and specificity of the fine needle aspiration biopsy of the thyroid: clinical point of view

INTRODUCTION

The rates of sensitivity and specificity of fine needle aspiration biopsy (FNAB) for the diagnosis of thyroid malignancy differ considerably among various reported series. These values are influenced by three factors: (a) whether only clearly positive and negative results are considered, or whether the commonly encountered 10-20% of indeterminate/suspicious ones are included; (b) whether adenomas are considered as neoplasms in one group with carcinomas; and (c) whether only histologically proven cases are used in calculations or whether patients with benign clinical follow-up are included.

AIM

The aim of the study was to evaluate the sensitivity and specificity of FNABs performed at this institution in the last 7 years from the clinical point of view, considering only benign vs. suspicious/malignant FNAB results (indicating surgery), and benign (including adenomas) vs. malignant definitive histology.

STUDY DESIGN

Retrospective study comparing pre-operative FNAB results with definitive histological examination after operation.

PATIENTS

A total of 2492 FNABs were performed in 2100 patients (1875 women and 225 men); their ages ranged from 9 to 85 years, with a median of 46 years. Clinical diagnosis was multinodular goitre in 1330, single nodule in 591, Hashimoto's thyroiditis in 147 and subacute thyroiditis in 32 cases. In 148 instances, the nodule was cystic. A history of previous treatment for carcinoma of the thyroid was present in 12 patients. Five hundred and thirty-six patients subsequently underwent thyroid surgery.

STATISTICS

The values of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy were calculated.

RESULTS

The sensitivity was 86%, specificity 74%, PPV 34%, NPV 97% and diagnostic accuracy 75%.

CONCLUSIONS

The specificity and positive predictive value are low when fine needle aspiration biopsy results are divided into two categories only (these being indication for surgery or not), and when only suspicious/malignant fine needle aspiration biopsies with subsequent malignant histology are considered to be true positive. Nevertheless, the ability to discriminate 11.7% of patients with a 34% probability of malignancy (suspicious/malignant cytology) from 81.2% of patients (benign cytology) with a probability of only 3% is very helpful.

Does a joint ultrasound guided cytology clinic optimize the cytological evaluation of head and neck masses?

AIM

To compare the results of fine-needle aspiration (FNA) of head and neck masses performed in an ultrasound-guided cytology clinic (USGCC) staffed by a radiologist and pathologist to those obtained with specimens sent from other sources.

METHODS

Comparison of broad-category FNA diagnoses (malignant, uncertain, benign or inadequate) with the patient's ultimate clinical or pathological outcome. Because FNA outcomes are semi-quantitative, accuracy of the procedure (the proportion of all tests resulting in a true- positive or negative fine-needle aspirate) is a better measure than sensitivity or specificity. Specimens (n = 292) from the first 2 years of the USGCC are compared with 600 specimens received from other sources over the previous 4 years.

RESULTS

Accuracy was 23.4% better for specimens from the USGCC compared with those obtained by clinician guided aspiration (83.9%, 95% CI 79.7-88.1%, vs 60.5%, 95% CI 56.6-64.4%). There was an 84% reduction in inadequate specimens (from 21.5% to 3.4%). The proportion resulting in an uncertain result did not alter; 12.0% for USGCC and 11.9% for clinician-derived specimens. Improvement in accurate identification of salivary gland, lymph node, soft tissue and thyroid pathology was 27.0%, 21.2%, 18.3% and 15.8% respectively.

CONCLUSIONS

The common practice of FNA performed by clinicians produces sub-optimal results in head and neck masses. A combined approach of ultrasound-guided fine-needle aspiration of head and neck masses, with immediate assessment of the material by a pathologist, is more accurate than with specimens obtained in other ways. If the results of FNA are to be incorporated into clinical decision making, the samples are best obtained using the USGCC model.