Thyroid nodules with FNA cytology suspicious for follicular variant of papillary thyroid carcinoma: follow-up and management

Application of the Bethesda system for reporting thyroid cytopathology for classification of thyroid nodules: A clinical and cytopathological characteristics in Bhutanese population

INTRODUCTION

The existence of baseline data on the spectrum of thyroid nodules in Bhutanese patients is unknown. Fine-needle aspiration cytology (FNAC) is regarded as the gold standard diagnostic test for pre-op assessment of thyroid lesions.

MATERIALS AND METHODS

We conducted a retrospective study, involving 765 patients who underwent FNAC of the thyroid gland, at Jigme Dorji Wangchuck National Referral Hospital, Thimphu, between January-2018 to December-2020. We aimed to assess the cytomorphological spectrum of thyroid nodules, classify them as per The Bethesda system for reporting thyroid cytopathology (TBSRTC), assess risk of malignancy (ROM), and evaluate the accuracy of FNAC in diagnosing thyroid malignancy.

RESULTS

Colloid nodule (37.4%) and papillary thyroid carcinoma (4.2%) constituted the majority of benign and malignant cytological diagnoses, respectively. According to TBSRTC, majority of the cases (82.0%) fell under the Bethesda II category. Bethesda III was the least common (1.4%) category. As compared to histopathological diagnosis; the sensitivity, specificity, positive and the negative predictive values of FNAC in diagnosing thyroid malignancy were 90.0%, 93.3%, 93.10%, and 90.32% respectively. The ROM increased concurrently with the grade of the Bethesda category and was more or less close to the ROM reference range, published in the TBSRTC.

CONCLUSION

Benign thyroid nodules (82.0%) constituted a majority of thyroid nodules in Bhutanese patients. FNAC was found to be reliable in detecting thyroid malignancy. From the literature, TBSRTC was found to be a more convenient method for reporting thyroid cytology. Henceforth, as most institutes, we plan to implement TBSRTC for reporting thyroid cytopathology.

Diagnosing atypia of undetermined significance in thyroid fine needle aspiration samples using nuclear scoring

BACKGROUND

Atypia of undetermined significance (AUS) is an indeterminate category in the Bethesda system for reporting thyroid cytopathology. Cytological features described as atypia are not always observed in every case, and it is difficult to determine how the small population of cells with enlarged nuclei, a few grooves, and rare elongated nuclei should be classified. Therefore, there is inter-intra observer variability considering these cell types, even though the cytological criteria are well defined. Therefore, this study aimed to establish a nuclear scoring system to help in the differential diagnosis of AUS.

METHODS

Fine needle aspiration (FNA) samples that showed AUS and had surgical follow-up were included in this study. The aspirate was scored for the presence of intanuclear cytoplasmic inclusions, nuclear grooves, overlapping, enlargement, and elongation individually. The total nuclear score for each case was calculated. Statistical analysis of the association between each nuclear feature and the presence of papillary thyroid cancer (PTC) in the surgical specimens was performed. Cut-off points from the total score of these nuclear features were also calculated.

RESULTS

Nuclear grooves and overlapping were more common in malignant cases (p < 0.001 and p = 0.048, respectively). A cut-off point of ≥5.5 for the total score was sensitive and specific for defining malignancy.

CONCLUSION

The risk of PTC was higher in nodules with more prominent nuclear overlapping or nuclear groove in their FNA samples. In order to achieve a more confident AUS diagnosis, our scoring system can be helpful for thyroid FNA samples.

Cytomorphological Analysis of Thyroid Nodules Diagnosed as Follicular Variant of Papillary Thyroid Carcinoma: a Fine Needle Aspiration Study of Diagnostic Clues in 42 Cases and the Impact of Using Bethesda System in Reporting-an Institutional Experience

Follicular variant of papillary thyroid carcinoma (FVPTC) is the second most common subtype of papillary thyroid carcinoma (PTC) after classical PTC (cPTC). Follicular thyroid lesions such as follicular adenomas/carcinomas, FVPTC, and noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) pose some diagnostic challenges for FNAC. In this study, we aimed to explore whether FNAC can demonstrate diagnostic clues by re-evaluating cytology slides from histopathologically diagnosed FVPTC cases. A total of 42 patients were enrolled in this study: patients were diagnosed with FVPTC via surgical resection between 2006 and 2016, and all patients were subjected to preoperative FNAC, which was conducted at either a private center or at the teaching hospital of Kocaeli University and reported by the same cytopathologist (NP). Clinical and cytomorphological characteristics were reviewed by both authors .Most cases (76.2%) are diagnosed either Bethesda IV or V. The majority of cases had a high cellularity (38/42; 90.5%), and the most frequent observations were monolayer and large syncytial groups of cells (95.2%). While microfollicular structures were observed in 30 (71.4%) cases, nuclear crowding and large naked nuclei were observed in all cases. Nuclear grooves were sparsely detected in 23 (54.8%) cases, and nuclear pseudoinclusions were detected in only six (14.3%) cases. Because thyrocytes often have a mixed architecture in FVPTC, despite a distinct follicular morphology, we believe that nuclear overcrowding, enlargement, and hyperchromasia in cases presenting with increased cellularity are notable clues for the cytodiagnosis of FVPTC. We believe that the primary aim of FNAC in such cases is to give preoperative diagnosis as either category IV or V. Nuclear crowding, monolayered clusters with large syncytial formations, nuclear enlargement, and hyperchromasia are notable cytomorphologic clues for the diagnosis of FVPTC on FNAC.

Ultrasound characteristics of thyroid nodules diagnosed as follicular neoplasms by fine-needle aspiration cytology

Cytopathological evaluation has been proven useful in the diagnostic work-up of “cold” nodules. The cytological diagnosis of follicular neoplasm usually requires histology to exclude malignancy. The objective of this prospective study was to test the hypothesis that ultrasound examinations show distinct characteristics in a subgroup of nodules which may attest the benign nature of a follicular neoplasm. Patients, methods: 56 patients (45 women, 11 men) were included in the study. All patients had a “cold” nodule which was diagnosed as follicular neoplasm. Consecutive histology revealed follicular adenomas (FTAs) (n = 44), follicular carcinomas (FTCs) (n = 7) and papillary carcinomas (PTCs) (n = 5), including follicular variant papillary carcinomas (fv PTCs) (n = 4). Ultrasound examinations were performed preoperatively. The ultrasound examinations were evaluated with respect to seven characteristics. Results: In 21 % of patients a follicular neoplasm was associated with a malignant and in 79 % of patients with a benign tumor as compared with histology. The ultrasound characteristics size 2 ml, round shape and homogeneous structure revealed significant differences for FTAs, FTCs and PTCs with p < 0.001, p = 0.003 and p = 0.027, resp. With respect to the benign nature of a follicular neoplasm maximum values for sensitivity and specificity were 0.75 and 0.83. Multivariate discriminant analysis revealed that ultrasound criteria were suitable to discriminate between benign vs. malignant nodules and among FTAs, FTCs and PTCs with correlation coefficients of r = 0.53 and r = 0.74, resp. Conclusions: in selected patients with higher operative risks and cytological diagnosis of follicular neoplasm ultrasound parameters may be helpful to assume a benign nature of the neoplasm and thus avoid the necessity of a histological work-up.

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features in the pediatric age group

BACKGROUND

The most common malignant thyroid neoplasm in children is papillary thyroid carcinoma (PTC). In 2015, the Endocrine Pathology Society introduced the terminology "noninvasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP) to replace the noninvasive follicular variant of PTC. The objective of the current study was to evaluate previously diagnosed PTC in the pediatric population, reappraise it for NIFTP, and discuss the impact of NIFTP on the risk of malignancy (ROM) for each The Bethesda System for Reporting Thyroid Cytopathology category in the pediatric population.

METHODS

The electronic databases of both study institutions were searched for all thyroidectomy specimens in patients aged <19 years from June 1, 2001 through June 1, 2016. The patient's age, sex, diagnosis, previous fine-needle aspiration cytology diagnosis, and follow-up were tabulated. Slides for available cases were reviewed and cases qualifying as NIFTP were separated.

RESULTS

The cohort included 101 resected nodules; cytological diagnoses were available for 95 cases. These cases included diagnoses of nondiagnostic (5 cases; 5.2%), benign (21 cases; 22.1%), atypia/follicular lesion of undetermined significance (9 cases; 9.5%), follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) (25 cases; 26.3%), suspicious for malignancy (7 cases; 7.4%), and malignant (28 cases; 29.5%). On the histological follow-up, 50 cases (49.5%) were benign, 49 cases (48.5%) were malignant, and 2 cases (1.9%) were NIFTP. These NIFTP cases originally were diagnosed as FNs on fine-needle aspiration cytology. The average ROM for FNs with and without NIFTPs was 28% and 25%, respectively CONCLUSIONS: According to our rate of 1.9% for NIFTPs on reappraisal for resected nodules, this entity is likely to be less frequent in the pediatric population due to the higher prevalence of PTCs and/or more aggressive variants. NIFTPs do not appear to affect the ROM for The Bethesda System for Reporting Thyroid Cytopathology categories in the pediatric population. However, large-scale studies are necessary to determine whether NIFTPs could affect the pediatric population. Cancer Cytopathol 2018;126:27-35. © 2017 American Cancer Society.

Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features: An Evidence-Based Nomenclature Change

A consensus panel recently used clinical evidence and pathologic parameters to rename noninvasive encapsulated follicular variant of papillary thyroid carcinoma to noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) to better reflect the indolent course of this tumor. NIFTP has stringent histopathologic diagnostic criteria established by the panel, including papillary-like nuclear features, and submission of the entire tumor capsule to exclude invasion. From a molecular standpoint, NIFTP is often characterized by RAS-type mutations, similar to other follicular-patterned lesions. While there has been prior evidence in the literature for the low malignant potential of these tumors, projects moving forward will help to independently reinforce the reliability of these criteria and nomenclature. With planned inclusion of NIFTP into the latest World Health Organization endocrine tumor classification scheme, this nomenclature shift provides a model for pathology efforts to refine diagnostic classifications to better guide treatment. In this review we discuss this nomenclature change and review the current literature.

Noninvasive Follicular Variant of Papillary Thyroid Carcinoma and the Afirma Gene-Expression Classifier

BACKGROUND

It is now recognized that noninvasive follicular variant of papillary thyroid carcinoma (NFVPTC) is a distinct subset of FVPTC with an exceedingly indolent clinical course. The Afirma gene-expression classifier (GEC) helps guide clinicians in the management of thyroid nodules with indeterminate fine-needle aspiration (FNA) results. Thyroid surgery is recommended for nodules with a suspicious Afirma result, whereas observation is deemed reasonable for most nodules with a benign result. The aim of this study was to confirm that the Afirma test detects NFVPTCs and to determine how many carcinomas detected by the Afirma GEC represent NFVPTCs.

METHODS

From a database of 249 FNAs sent for Afirma testing between January 2012 and October 2014, a search was conducted for cases with a preceding FNA diagnosis of atypia/follicular lesion of undetermined significance (AUS/FLUS) or suspicious for a follicular neoplasm (SFN), a suspicious Afirma result, and a corresponding resection specimen reviewed at Brigham and Women's Hospital. The diagnoses of the prior FNAs and subsequent resection specimens were recorded. Slides for all resection specimens with a diagnosis of FVPTC were reviewed to identify NFVPTCs.

RESULTS

Sixty-three cases met the inclusion criteria. The preceding FNA diagnosis was AUS/FLUS in 34 (54%) cases and SFN in 29 (46%) cases. The surgical resection specimen demonstrated 16 (25%) FVPTCs, five (8%) follicular thyroid carcinomas, one (2%) classical type PTC, and 41 (65%) benign tumors/nodules. Of the 16 FVPTCs, 14 (88%) were NFVPTCs. Thus, NFVPTCs accounted for 64% of the carcinomas in the cohort.

CONCLUSION

These results indicate that the Afirma GEC detects NFVPTCs and that many of the carcinomas detected by Afirma are NFVPTCs. While all care should be individualized and include clinical and sonographic assessment, these results suggest lobectomy as opposed to total thyroidectomy should be considered for nodules with a preceding AUS/FLUS or SFN on cytology and a suspicious Afirma result.

Fine-needle aspiration diagnoses of noninvasive follicular variant of papillary thyroid carcinoma

OBJECTIVES

Endocrine pathologists are reconsidering whether tumors characterized as noninvasive follicular variant of papillary thyroid carcinoma (NFVPTC) warrant a diagnosis of carcinoma. A change in terminology would affect cytology diagnoses; thus, our aim was to study the preceding fine-needle aspiration (FNA) diagnoses of this group of tumors.

METHODS

We evaluated the FNA diagnoses of a primary cohort of 72 consecutively resected NFVPTCs and the cytologic and molecular features of an additional cohort of 39 tumors that included both NFVPTCs and classical papillary thyroid carcinomas (cPTCs).

RESULTS

For our primary cohort, the preceding FNA diagnosis associated with the highest risk of malignancy was suspicious for PTC in nearly half (48.6%) of cases. In contrast to the majority of cPTCs, no NFVPTCs in our second cohort had papillae or pseudoinclusions on cytologic evaluation of the FNA specimens, and none harbored a BRAF V600E mutation.

CONCLUSIONS

If NFVPTCs were no longer termed carcinomas, this would affect the rate of malignancy of FNA diagnostic categories. Cytologic and molecular features could aid in identifying NFVPTCs at the time of FNA diagnosis.

Follicular variant of papillary thyroid carcinoma: accuracy of FNA diagnosis and implications for patient management

Follicular variant of papillary thyroid carcinoma (FVPTC) creates a continuous diagnostic dilemma among pathologists because of the paucity of nuclear changes of papillary carcinoma and overlapping features with benign and other neoplastic follicular lesions. Current guidelines for the management of thyroid nodules recommend surgery for confirmed PTC, suspicious for PTC, and follicular neoplasm cases, while further immediate diagnostic studies or treatment are not routinely required if the nodule is benign on cytology. This study is designed to determine the accuracy of cytology in the diagnosis of FVPTC, based on the Bethesda classification system, and determine the implications for patient management based on the current recommendation. Based on a retrospective review of cytologic diagnoses between January 2008 and December 2011, thyroid fine needle aspiration (FNA) cytology specimens with subsequent surgical intervention and a final diagnosis of FVPTC were selected. The cytologic diagnoses were compared with the final diagnoses, and the percentage of cases contributing to the final diagnosis of FVPTC was calculated for each diagnostic category. Triage efficiency and diagnostic accuracy were calculated. One hundred and fifty-two cases with histologic confirmation of FVPTC were identified (representing 128 patients-101 female, 27 male). All patients had undergone either lobectomy with completion thyroidectomy or total thyroidectomy. The cytologic diagnosis of "positive for malignancy" accounted for only 27 % of the final histologic diagnosis of FVPTC, while suspicious for carcinoma, follicular neoplasm, follicular lesion of undetermined significance, and benign accounted for 11, 23, 23, and 16 % of the final diagnosis of FVPTC, respectively. Only 18 % of the 55 cases tested were positive for BRAF mutation. The subtle nuclear features of FVPTC pose challenges for an accurate diagnosis. Therefore, a better approach is to triage these cases for surgical intervention and/or further evaluation of the particular nodule. Our triage efficacy for FVPTC was 84 %; however, the diagnostic accuracy of PTC was 38 %. A negative diagnosis on FNA has diagnostic and management implications for up to 16 % of cases because they may have no further immediate diagnostic studies or treatment. BRAF mutation analysis provides minimal effect on diagnostic accuracy.

Risk stratification in follicular neoplasm: a cytological assessment using the modified Bethesda classification

BACKGROUND

The 2007 Bethesda classification for thyroid cytology defines follicular neoplasm as a category of cases with cellular specimens demonstrating abundant follicular cells arranged in a microfollicular pattern with little or no colloid. The current recommendation for the management of these cases is diagnostic lobectomy. There has been great difficulty and variability in triaging and reporting follicular neoplasm. To increase diagnostic accuracy, at the study institution, this category is subclassified further into 3 categories: 1) microfollicular-patterned neoplasm (MN); 2) Hürthle cell neoplasm (HN); and 3) follicular lesion with some features suggestive of but not diagnostic of the follicular variant of papillary thyroid carcinoma (FL). The authors reviewed the cases of follicular neoplasm observed over a period of 5 years to document the follow-up trend using this modified classification.

METHODS

A search of the cytology records was performed for the period between January 2008 and December 2012. All thyroid fine-needle aspiration cases were reviewed and those with a diagnosis of follicular neoplasm (including Hürthle cell neoplasm) were identified. Correlating follow-up surgical pathology reports were reviewed.

RESULTS

A total of 399 cases of follicular neoplasm with surgical follow-up were identified. Malignancy was identified in 32% of all cases of follicular neoplasm and was found to be disproportionately higher in the FL category (73%). A cytological diagnosis of FL is more likely to be called malignant (73%) than benign neoplastic (9%) or benign nonneoplastic (18%). A cytological diagnosis of MN or HN is more likely to be benign neoplastic (46% and 46%, respectively) than malignant (29% and 26%, respectively) or benign nonneoplastic (25% and 28%, respectively). Of the cytological features examined, 2 (nuclear enlargement and nuclear grooves) were significantly associated with the follicular variant of papillary thyroid carcinoma.

CONCLUSIONS

The results of the current study clearly indicate that follicular lesions with even subtle nuclear atypia have a high positive predictive value for malignancy and therefore should be distinguished from other follicular lesions because these cases require more aggressive surgical management. The current study also raises an important issue concerning the current thyroid classification based on the 2007 Bethesda classification for thyroid cytology. Future thyroid fine-needle aspiration classification schemes should consider subclassifying follicular neoplasms for the purpose of risk stratification.

Aggressive variants of follicular cell-derived thyroid carcinomas: a cytopathologist's perspective

Follicular cell-derived carcinomas of the thyroid gland comprise a heterogeneous group of malignant neoplasms of the thyroid gland with varied histologic appearance and molecular profiles. In most patients, these tumors represent relatively indolent neoplasms; however, certain subtypes/variants behave in an aggressive manner, and the recognition of this subset of tumors is essential because of their variable response to therapy and significant morbidity and mortality. Fine-needle aspiration is considered an essential tool for the diagnosis of suspicious thyroid nodules. In this review, the authors discuss the clinical, histologic, and molecular findings and the prognostic implications of aggressive thyroid neoplasms with emphasis on the characteristic cytomorphologic features on fine-needle aspiration smears.

Follicular variant of papillary thyroid carcinoma: cytological indicators of diagnostic value

BACKGROUND

Fine needle aspiration cytology (FNAC) is an important investigation in preoperative diagnosis of thyroid lesions. Follicular variant of papillary carcinoma thyroid (FVPTC) is a well defined entity in histopathology, but its diagnosis in FNAC is usually missed and is challenging compared to classic papillary thyroid carcinoma.

AIMS

The purpose of this study is to retrospectively analyze cytological features in histologically confirmed cases of FVPTC, compare them with literature and document the features that could increase the sensitivity of FNAC diagnosis.

MATERIALS AND METHODS

Cytological smears from 22 histologically confirmed cases of FVPTC were evaluated for microscopic pattern and nuclear features by two independent pathologists and results compared with previous studies. Statistical analysis was done based on bivariate Pearson's correlation coefficient.

RESULTS

Among 22 cases 21 were female and one male with age range 21 - 50 years. All patients had a solitary nodule except one with multicentric presentation. Preoperative cytological diagnosis were, classic papillary thyroid carcinoma (PTC); 7, FVPTC; 3, suspicious for PTC; 4, follicular neoplasm; 5 and adenomatous goiter;3. Diagnosis upon cytological review were, FVPTC; 11, classic PTC; 7 , suspicious for PTC; 2, follicular adenoma;1 and adenomatous goiter; 1.

CONCLUSION

We conclude that cellular smears with features as observed in our case like microfollicular pattern, syncytial clusters, fine powdery chromatin, anisonucleosis and nucleomegaly should alert the pathologist to look carefully for other more specific features like nuclear grooves and nuclear pseudoinclusions. This approach will help in avoiding misdiagnosis of FVPTC and would aid in choosing the right treatment modality.

A simplified economic approach to thyroid FNA cytology and surgical intervention in thyroid nodules

Objective

Few studies have modelled the economics of thyroid FNA.

Methods

A simple spreadsheet economic model for delivery of thyroid fine needle aspiration (FNA) cytology is described using the UK Royal College of Pathologists’ Classification for thyroid FNA which is based on The Bethesda System for Reporting Thyroid Cytopathology.

Results

We show an estimated 27.8% cost treatment reduction per patient if low rates of non-diagnostic for cytological diagnosis (Thy 1) and neoplasm possible atypia/non-diagnostic (Thy 3a) are achieved, which require rapid onsite FNA adequacy assessment of aspiration samples. If we assume that the number of thyroid FNAs performed in the UK annually is around 500 per million, and the UK population is 62 million, this could save the UK National Health Service significant sums, as the additional cost per patient treated in this model varies from £781 for a scenario with ultrasound guided FNA and inclinic cell adequacy assessment to £998 where aspirates are taken in conventional fashion without any inclinic adequacy assessment.

Conclusions

This model makes a strong economic case for the introduction of rapid onsite assessment of thyroid FNA across cancer networks, to improve the diagnostic efficacy of thyroid FNA.

Employing genetic markers to improve diagnosis of thyroid tumor fine needle biopsy

Fine-Needle Aspiration (FNA) is the most widely used and cost-effective preoperative test for the initial evaluation of a thyroid nodule, although it has limited diagnostic accuracy for several types of tumors. Patients will often receive cytological report of indeterminate cytology and are referred to surgery for a more accurate diagnosis. An improved test would help physicians rapidly focus treatment on true malignancies and avoid some unnecessary treatment of benign tumors. This review will discuss current molecular markers that may improve thyroid nodule diagnosis.

Ultrasound-guided fine-needle aspiration biopsy of the thyroid: methods to decrease the rate of unsatisfactory biopsies in the absence of an on-site pathologist

PURPOSE

The rate of unsatisfactory samples from ultrasound-guided fine-needle aspirations of thyroid nodules varies widely in the literature. We aimed to evaluate our thyroid ultrasound-guided fine-needle aspiration biopsy technique in the absence of on-site microscopic examination by a pathologist; determine factors that affect the adequacy rate, such as the number of needle passes and needle size; compare our results with the literature; and establish an optimal technique.

MATERIALS AND METHODS

We performed a retrospective review of cytopathology reports from 252 consecutive thyroid ultrasound-guided fine-needle aspiration biopsies performed by a radiologist between 2005 and 2010 in our hospital's radiology department. Sample adequacy, the number of needle passes, and needle size were determined. There was an on-site cytologist who prepared slides immediately after fine-needle aspiration but no on-site microscopic assessment of sample adequacy to guide the number of needle passes that should be performed. Cytopathology biopsy reports were classified as either unsatisfactory or satisfactory samples for diagnosis; the latter consisted of benign, malignant, and undetermined diagnoses.

RESULTS

Seventy-seven biopsies were performed with 1 needle pass, 124 with 2 needle passes, and 51 with 3 needle passes. The rates of unsatisfactory biopsies were 33.8%, 23.4% (odds ratio [OR] 0.599 [95% confidence interval {CI}, 0.319-1.123]; P = .110), and 13.7% (OR 0.312 [95% CI, 0.124-0.788]; P = .014), respectively.

CONCLUSION

In a hospital in which there is no on-site pathologist, a 3-pass method increases the specimen satisfactory rate by 20% compared with 1 pass, achieves similar rates to the literature, and provides a basis for further improvement of our practice.

Features associated with locoregional spread of papillary carcinoma correlate with diagnostic category in the Bethesda System for reporting thyroid cytopathology

BACKGROUND

Most malignancies identified by thyroid fine-needle aspiration (FNA) are papillary thyroid carcinoma (PTC). This study sought to determine if clinically adverse features of PTC correlate with the preceding cytologic diagnosis.

METHODS

Thyroid FNA diagnoses were correlated with subsequent histopathologic findings.

RESULTS

From 6175 thyroid FNAs, histologic follow-up confirmed PTC in 52 of 184 (28%) FNAs with atypia of undetermined significance (AUS), 52 of 190 (27%) FNAs suspicious for follicular neoplasm, 182 of 229 (79%) FNAs that were suspicious for malignancy, and 188 of 198 (95%) FNAs that were malignant (M). Sex, age, and disease multifocality did not differ among FNA diagnosis groups. However, PTCs following an M FNA were more likely to have a higher American Joint Committee on Cancer T and N stage, and have lymphovascular invasion and/or extrathyroidal extension. Two patients had distant metastasis at initial surgery, whereas 16 developed subsequent recurrence and/or metastasis; all had a preceding M FNA. High-risk histologic subtypes of PTC also stratify to the M category, accounting at least partly for the association of cytologic diagnosis with adverse pathological parameters. Conversely, follicular variants of PTC predominate in non-M categories.

CONCLUSIONS

The Bethesda System for Reporting Thyroid Cytopathology conveys malignancy risk, but also predicts the presence of pathological risk factors and disease progression when the malignancy is PTC. M diagnoses identify higher risk PTCs, whereas AUS diagnoses identify low-risk PTCs, mostly follicular variants. These findings support the concept of conservative clinical management for some patients with AUS, while suggesting that a central neck dissection may be routinely justified in some patients with a M FNA.

Morphological and immunocytochemical diagnosis of thyroiditis: Comparison between conventional and liquid-based cytology

The efficacy of thyroid (FNAB) processed by liquid-based cytology (LBC) in Hashimoto's Thyroiditis (HT) in two reference periods, is evaluated. The morphologic features of 820 cases with both methods and the cyto-histological comparison are analyzed. The diagnosis of hyperplastic nodules (HN) in HT, its mimickers especially in presence of oxyphilic cells and the role of immunocytochemistry (IHC) are studied. 150 cases of HT processed by conventional smear (CS) in 1996-98 and 670 with LBC in 2005-2007,were included. The majority of FNAB were carried out under USguidance and fixed with ethyl alcohol for the CS. LBC material was rinsed in the Cytolit solution, processed according to the manufacturer's recommendations. Among the 150 CS, 83 were HT while 67 were HN in HT; in the second triennium 245 LBC were HT and 425 were HN in HT. In the first period a follow-up (including a second FNA or surgery) was done in 92 cases, in the second period in 116. In the surgical group 97.1% in the first period were benign (all HT and 34/36 HN) and 2.8% malignant(all HN). In 2005-2007, 94% were benign (15 HT and 45/49 HN) and 6%malignant. Thirty HN from the second triennium had ICC for HBME-1 and Galectin-3 resulting negative in 93.5%. Among these cases, 10 had a benign histology and a concordant negative ICC. LBC can be used as a valid method for HT, especially for the possible application of ICC to HN, and it allows a correct preoperative selection of lesions

The bethesda system for reporting thyroid cytopathology: interpretation and guidelines in surgical treatment

OBJECTIVES

(1) The aim of this study is to assess the efficacy of The Bethesda System for Reporting Thyroid Cytology (TBSRTC) in accurate prediction of thyroid lesions on fine needle aspiration (FNA). (2) To appraise the surgeon with guidelines for adequacy of samples, and interpretation of FNA reports with TBSRTC and hence aiding them in surgical decision making. Five hundred and sixty four FNAs were done on patients with thyroid swellings in the department of Pathology and reported using TBSRTC guidelines. In cases where surgery was done, histopathological report was correlated. Using TBSRTC the commonest cytological diagnosis was benign-Hashimotos thyroiditis followed by benign follicular nodule. TBSTRC reduces inter-observer variability in reporting thyroid FNAs and provides good communication between the surgeon and pathologist. It also implicates guidelines for cancer risk and clinical management to the surgeons, thus avoiding unnecessary surgery.

Subclassification of the "grey zone" of thyroid cytology; a retrospective descriptive study with clinical, cytological, and histological correlation

Undetermined thyroid cytology precludes any definitive distinction between malignant and benign lesions. Recently several classifications have been proposed to split this category into two or more cytological subcategories related to different malignancy risk rates. The current study was performed retrospectively to investigate the results obtained separating “undetermined” cytologic reports into two categories: “follicular lesion” (FL) and “atypia of undetermined significance” (AUS). Biochemical, clinical, and echographic features of each category were also retrospectively analyzed. Altogether, 316 undetermined fine-needle aspirated cytologies (FNACs) were reclassified as 74 FL and 242 AUS. Histological control leads to a diagnosis of carcinomas, adenomas, and nonneoplastic lesions, respectively, in 42.2%, 20%, and 37.8% of AUS and in 8.3%, 69.4%, and 22.2% of FL. Among biochemical, clinical, cytological, and echographic outcomes, altered thyroid autoantibodies, multiple versus single nodule, AUS versus FL, and presence of intranodular vascular flow were statistically significant to differentiate adenoma from carcinoma and from nonneoplastic lesions, whereas no significant differences were found between carcinomas and nonneoplastic lesions for these parameters. The results of this retrospective study show that undetermined FNAC category can further be subclassified in AUS and FL, the former showing higher malignancy rate. Further prospective studies are needed to confirm our results.

Can misdiagnosis in pre-operative FNAC of thyroid nodule influence surgical treatment?

BACKGROUND

Pre-operative cytology in thyroid disease remains the most appropriate diagnostic test for defining the nature of a thyroid nodule before surgical excision.

MATERIALS AND METHODS

We selected the most recent 825 surgical thyroid procedures performed in our institution from January 2004 to June 2007; 776 were total thyroidectomies, 23 were lobe-isthmectomies, and 26 were radical neck dissections. We distributed the data based on pre-operative cytology. Each cytological diagnosis was compared to results obtained by definitive histology. Tumors were called incidentalomas if they consisted of a neoplastic focus with a low grade of aggressiveness, as demonstrated by dimension <5 mm, non-aggressive histological subtype.

RESULTS

Of the 541 cases of benign disease, 417 were confirmed as benign. The other 124 cases are listed as follows: 29 follicular adenoma; 76 papillary carcinoma (35 found as incidentalomas), and 19 follicular carcinoma (3 incidentalomas). Cytology suggestive of papillary carcinoma was correct in 95.2% of cases (119/125). The 135 tumors termed "follicular neoplasm" were staged on pathology thus: 56 adenoma (41.4%), 26 carcinoma (19.2%), 13 (9.6%) absence of follicular proliferation, 38 (28.1%) papillary follicular variant, 2 (1.4%) undifferentiated cells. Medullary carcinomas were both confirmed. The "suspicious group" exhibited no malignancy on fine needle aspiration cytology (12 of 21; 57%).

CONCLUSIONS

Cytology has good reliability in malignant lesions. Incidental tumors occurring in benign disease have little impact on clinical and surgical management; "follicular neoplasm" posed two problems - the impossibility of identifying the nature of the tumor, as well as the newer difficulty in distinguishing papillary follicular subtype.

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.

Fine-needle aspiration in the work-up of thyroid nodules

Fine-needle aspiration (FNA) is the crucial diagnostic test used for the evaluation of patients with a thyroid nodule. The result of an FNA determines if a patient can be followed with repeated examinations or referred for surgery. The value of FNA can be enhanced by attention to technical details. Communication between operator and pathologist is essential. A pathologist's interpretation is aided if essential clinical information is provided on a requisition form. Although reporting terminology has been varied and confusing in the past, a proposal for a uniform reporting system provides 6 clearly defined and clinically relevant reporting categories and promises to standardize the reporting of thyroid FNA results.

Differential diagnosis of thyroid nodules using fine-needle aspiration cytology and oncogene mutation screening: are we ready?

Thyroid nodules are a very common clinical finding, and although the majority of them are benign, thyroid carcinoma accounts for about 5-15% of nodules. Fine-needle aspiration cytology (FNAC) is actually used for the differential diagnosis of these lesions. Although in most cases this examination clearly distinguishes benign from malignant lesions, some fine-needle aspiration (FNA) samples fall into undetermined thyroid cytology categories, which according to the most recent classification of thyroid FNAC consist of ‘suspicious for malignancy’, ‘suspicious for follicular or Hurtle cell neoplasm’, and ‘follicular lesion of undetermined significance/atypia of undetermined significance’. Moreover, some samples are insufficient for diagnosis. Taken together, these categories account for almost 20-30% of nodules. Owing to the high risk of papillary thyroid carcinoma, patients with lesions that are ‘suspicious for malignancy’ are currently subjected to lobectomy or total thyroidectomy. On the other hand, patients with ‘atypia of undetermined significance’ undergo repeated FNAs, and patients with ‘suspicious for follicular or Hurtle cell neoplasm’ are subjected to diagnostic lobectomy and subsequently, in the case of histological diagnosis of carcinoma, total thyroidectomy. Recent studies clearly indicate that molecular analysis of thyroid nodules can significantly improve the diagnostic power of cytology and drive the appropriate clinical management of these patients.

Is a five-category reporting scheme for thyroid fine needle aspiration cytology accurate? Experience of over 18,000 FNAs reported at the same institution during 1998-2007

OBJECTIVE

Fine needle aspiration (FNA) has long been recognized as an essential technique for the evaluation of thyroid nodules. Although specific cytological patterns have been recognized, a wide variety of reporting schemes for thyroid FNA results have been adopted. This study reports our experience with a five-category reporting scheme developed in-house based on a numeric score and applied to a large series of consecutive thyroid FNAs. It focuses mainly on the accuracy of thyroid FNA as a preoperative test in a large subset of histologically distinct thyroid lesions.

METHODS

During the 1998-2007 period, 18,359 thyroid ultrasound-guided FNAs were performed on 15,269 patients; FNA reports were classified according to a C1-C5 reporting scheme: non-diagnostic (C1), benign (C2), indeterminate (C3), suspicious (C4), and malignant (C5).

RESULTS

Non-diagnostic (C1) and indeterminate (C3) FNA results totalled 2,230 (12.1%) and 1,461 (7.9%), respectively, while suspicious (C4) and malignant (C5) results totalled 238 (1.3%) and 531 (2.9%), respectively. Histological results were available in 2,047 patients, with thyroid malignancy detected in 840. Positive predictive value of FNA was 98.1% with a 49.0 likelihood ratio (LR) of malignancy in patients with a C4/C5 FNA report.

CONCLUSIONS

This five-category scheme for thyroid FNA is accurate in discriminating between the virtual certainty of malignancy associated with C5, a high rate (92%) of malignancy associated with C4, and a 98% probability of a histological benign diagnosis associated with C2. Further sub-classifications of C3 may improve the accuracy of the diagnostic scheme and may help in recognizing patients eligible for a 'wait and see' management.

Genetic markers differentiating follicular thyroid carcinoma from benign lesions

Thyroid nodules are commonly encountered during routine medical care. The main problem established by a discovery of a thyroid nodule is to discriminate between a benign and malignant lesion. Fine-needle aspiration (FNA) is the most widely used and cost-effective preoperative test for initial evaluation of a thyroid nodule. While the overall accuracy of FNA for classical papillary thyroid carcinoma (PTC) approaches 100%, it has limited accuracy with follicular lesions. Patients with a cytological report of indeterminate or follicular lesions are referred to surgery for a more accurate diagnosis. A more acute molecular-based test for thyroid nodules is needed not only to improve treatment decisions, but also to potentially reduce the long-term health costs. Several studies have looked into biologic markers that could be used as an adjuvant to distinguish the benign from malignant nodules. This review will focus on those biomarkers that are potentially useful in the diagnosis of thyroid lesions commonly classified as indeterminate.

The Bethesda System For Reporting Thyroid Cytopathology

To address terminology and other issues related to thyroid fine-needle aspiration (FNA), the National Cancer Institute (NCI) hosted the NCI Thyroid FNA State of the Science Conference. The conclusions regarding terminology and morphologic criteria from the NCI meeting led to the Bethesda Thyroid Atlas Project and form the framework for The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). For clarity of communication, TBSRTC recommends that each report begin with 1 of 6 general diagnostic categories. The project participants hope that the adoption of this flexible framework will facilitate communication among cytopathologists, endocrinologists, surgeons, radiologists, and other health care providers; facilitate cytologic-histologic correlation for thyroid diseases; facilitate research into the epidemiology, molecular biology, pathology, and diagnosis of thyroid diseases; and allow easy and reliable sharing of data from different laboratories for national and international collaborative studies.

The Bethesda System for Reporting Thyroid Cytopathology

OBJECTIVE

To address terminology and other issues related to thyroid fine-needle aspiration (FNA), the National Cancer Institute (NCI) hosted The NCI Thyroid FNA State of the Science Conference. The conclusions regarding terminology and morphologic criteria from the NCI meeting led to the Bethesda Thyroid Atlas Project and form the framework for the Bethesda System for Reporting Thyroid Cytopathology.

DESIGN

Participants of the Atlas Project were selected from among the committee members of the NCI FNA State of the Science Conference and other participants at the live conference. The terminology framework was based on a literature search of English language publications dating back to 1995 using PubMed as the search engine; online forum discussions ( http://thyroidfna.cancer.gov/forums/default.aspx ); and formal interdisciplinary discussions held on October 22 and 23, 2007, in Bethesda, MD.

MAIN OUTCOME

For clarity of communication, the Bethesda System for Reporting Thyroid Cytopathology recommends that each report begin with one of the six general diagnostic categories. Each of the categories has an implied cancer risk that links it to an appropriate clinical management guideline.

CONCLUSIONS

The project participants hope that the adoption of this framework will facilitate communication among cytopathologists, endocrinologists, surgeons, and radiologists; facilitate cytologic-histologic correlation for thyroid diseases; facilitate research into the understanding of thyroid diseases; and allow easy and reliable sharing of data from different laboratories for national and international collaborative studies.

A meta-analysis of comparing fine-needle aspiration and frozen section for evaluating thyroid nodules

The literature on comparing fine-needle aspiration (FNA) and frozen section for evaluating thyroid nodules was reviewed. Publications on this subject were divided into three groups (follicular lesions, non-follicular lesions and thyroid lesions, not otherwise specified). A meta-analysis was done to compare sensitivity, specificity, and positive and negative predictive values between FNA and frozen section diagnoses. For follicular lesions, FNA was much more sensitive but less specific, with lower positive predictive value than frozen section. FNA and frozen section are virtually identical in all parameters of accuracy in evaluating thyroid nodules that are not follicular lesions. The third group of publications that did not separate/specify follicular lesions from non-follicular lesions was non-contributory.

Relevance of immunocytochemistry on thin-layer cytology in thyroid lesions suspicious for medullary carcinoma: a case-control study

BACKGROUND

Fine needle aspiration cytology represents the most important tool in the diagnosis of thyroid nodules, mostly in discriminating malignant from benign lesions. The diagnosis of medullary thyroid carcinoma (MTC) may present some problems related to its deceptive morphologic picture. This diagnosis may be supported by immunocytochemistry (ICC), which may be difficult to carry out on the conventional smears.

DESIGN

The diagnostic efficacy of ICC for the diagnosis of MTC with respect to other thyroid neoplasms on slides processed by thin-layer cytology (TLC) is evaluated.

PATIENTS

In the period between January 2002 and December 2005, 8,200 FNAB were processed. ICC on TLC slides was required in 33 cases. Conventional smears were fixed in ethanol, whereas TLC slides were processed with the Thin Prep 2000 method. All slides were then stained with Papanicolaou. In all cases where MTC was morphologically suspected, ICC for calcitonin, monoclonal carcinoembryonic antigen, and thyroglobulin was carried out only on TLC slides.

RESULTS

Thirty-three thyroid cytologic cases had ICC on the TLC slides, including 22 follicular proliferations and 11 malignant lesions. The application of ICC on TLC was conclusive in 32 cases and inconclusive in 1 case. Twenty cases underwent surgery. No false-positive and false-negative cases were found. Sensitivity and specificity were 100%, and the overall diagnostic accuracy was 100%.

CONCLUSIONS

ICC can be successfully applied on TLC slides. The combined results of morphology and a small immunopanel including thyroglobulin, calcitonin, and carcinoembryonic antigen yields a 100% diagnostic efficacy for MTC.

CONDENSED ABSTRACT

Fine needle aspiration cytology is an excellent technique for diagnosing malignant neoplasms of the thyroid, especially those derived from the follicular cells. A correct preoperative diagnosis of C-cell-derived tumors (MTC), which is essential for both the surgical approach to the primary tumor and the management of the patient, should rely not only on the morphologic picture but also on the immunocytochemical yielding using an immunopanel, which is particularly satisfactory on the TLC slides.

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/).

Sonographically guided fine needle aspiration of thyroid nodule: discrepancies between cytologic and histopathologic findings

PURPOSE

To analyze the discrepancies between the cytologic results of sonographically (US)-guided fine needle aspiration (FNA) of thyroid nodules and final histopathologic results and to discuss the limitations of US-guided FNA.

MATERIALS AND METHODS

The results of US-guided FNAs performed by a single experienced radiologist in 315 thyroid nodules in 292 patients (246 women, 46 men aged 12-79 years) were retrospectively correlated with their surgical pathologic results. The FNA results were classified as nondiagnostic, indeterminate, negative, or positive, whereas final pathologic diagnoses were classified as malignant or benign.

RESULTS

The FNA results were nondiagnostic in 31 cases (9.8%), indeterminate in 97 cases (30.8%), and determinate in 187 cases (59.4%). Of the 187 conclusive cases, 169 (90.4%) were concordant with the final pathologic results, whereas 18 (9.6%) were discordant with 14 false-positive and 4 false-negative results. These discrepancies were caused by atypical nuclear features. Among the 97 indeterminate and 31 nondiagnostic cases, a malignancy was found in 14 (14.4%) and 8 (25.8%) cases, respectively. In addition, 10 papillary carcinomas, which were not visualized on sonograms, were detected incidentally in thyroidectomy specimens.

CONCLUSION

The diagnostic accuracy of US-guided FNA of thyroid nodule has limitations that should be minimized by careful interpretation of the cytologic findings and accurate sampling.

Diagnosis of suspicious thyroid nodules using four protein biomarkers

PURPOSE

Fine-needle aspiration (FNA) cytology, a standard method for thyroid nodule diagnosis, cannot distinguish between benign follicular thyroid adenoma (FTA) and malignant follicular thyroid carcinoma (FTC). Previously, using expression profiling, we found that a combination of transcript expression levels from DDIT3, ARG2, C1orf24, and ITM1 distinguished between FTA and FTC. The goal of this study was to determine if antibody markers used alone or in combination could accurately distinguish between a wider variety of benign and malignant thyroid lesions in fixed sections and FNA samples.

EXPERIMENTAL DESIGN

Immunohistochemistry was done on 27 FTA, 25 FTC, and 75 other benign and malignant thyroid tissue sections using custom antibodies for chromosome 1 open reading frame 24 (C1orf24) and integral membrane protein 1 (ITM1) and commercial antibodies for DNA damage-inducible transcript 3 (DDIT3) and arginase II (ARG2). FNA samples were also tested using the same antibodies. RNA expression was measured by quantitative PCR in 33 thyroid lesions.

RESULTS

C1orf24 and ITM1 antibodies had an estimated sensitivity of 1.00 for distinguishing FTA from FTC. For the expanded analysis of all lesions studied, ITM1 had an estimated sensitivity of 1.00 for detecting malignancy. Because all four cancer biomarkers did well, producing overlapping confidence intervals, not one best marker was distinguished. Transcript levels also reliably predicted malignancy, but immunohistochemistry had a higher sensitivity. Malignant cells were easily detected in FNA samples using these markers.

CONCLUSIONS

We improved this diagnostic test by adding C1orf24 and ITM1 custom antibodies and showing use on a wider variety of thyroid pathology. We recommend that testing of all four cancer biomarkers now be advanced to larger trials. Use of one or more of these antibodies should improve diagnostic accuracy of suspicious thyroid nodules from both tissue sections and FNA samples.

Nódulos com diagnóstico de padrão folicular: marcadores biológicos são o futuro?

Com o uso da ultra-sonografia de alta resolução, a prevalência de nódulos tem aumentado e, conseqüentemente, o número de punção aspirativa por agulha fina (PAAF), que é o método de escolha para diagnóstico inicial. Um dos maiores dilemas clínicos para o citologista é o diagnóstico diferencial das lesões foliculares comumente agrupadas na classe padrão folicular. Neste artigo de revisão, discutiremos quais são as lesões que podem ser assim classificadas e os marcadores moleculares, identificados por nós ou por outros grupos, que são capazes de distinguir as lesões benignas das malignas.

Intraoperative pathologic examination: cost effectiveness and clinical value in patients with cytologic diagnosis of cellular follicular thyroid lesion

OBJECTIVE

Routine use of intraoperative pathologic examination (IOPE), including frozen section (FS) and scrape preparation cytology (SPC), during diagnostic thyroid lobectomy continues to be a source of controversy. We sought to better delineate the usefulness and cost-benefit ratio of IOPE in the context of cytologically diagnosed cellular follicular lesion (CFL) or follicular neoplasm (FN).

DESIGN

Records of 205 patients who underwent thyroidectomy for cytologically diagnosed FN or CFL between 1997 and 2005 were retrospectively reviewed. IOPE results, patient demographics, and tumor characteristics were correlated to final histopathologic diagnoses. Sensitivity, specificity, predictive values, accuracy, and costs of IOPE were calculated.

MAIN OUTCOME

IOPE correctly identified 3 of 16 follicular carcinomas and 9 of 36 papillary carcinomas. Sensitivity, specificity, and accuracy were 23%, 99%, and 78%, respectively. On univariate analysis, malignancy risk among follicular nodules did not correlate with age, gender, or nodule size. On multivariate analysis, nodule size was predictive of malignancy (p < 0.05). Over the entire patient series, routine IOPE resulted in a net cost savings of $74,304.33.

CONCLUSIONS

IOPE reduced costs and limited the number of completion thyroidectomies necessary. IOPE is specific, cost effective, and of minimal additional risk when performed routinely for patients with CFL or FN.

Our approach to follicular-patterned lesions of the thyroid

Follicular-patterned lesions of the thyroid are common; these include hyperplastic/adenomatoid nodules, follicular adenoma, follicular carcinoma and follicular variants of papillary carcinoma. Most of these lesions can be diagnosed with ease; however, there is a controversial subgroup. In this review, we present our diagnostic approach based on our experience with the histological diagnosis of these tumours, which can help in appropriate clinical management.

Current status of fine needle aspiration for thyroid nodules

When not to perform fine needle aspiration of a thyroid nodule In summary, FNA of thyroid nodules has become one of the most useful, safe, and accurate tools in the diagnosis of thyroid pathology. Thyroid nodules that should be considered for FNA include any firm, palpable, solitary nodule or nodule associated with worrisome clinical features (rapid growth, attachment to adjacent tissues, new hoarseness, or palpable lymphadenopathy). FNA should also be performed on nodules with suspicious ultrasonographic features (microcalcifications, rounded shape, predominantly solid composition); dominant or atypical nodules in multinodular goiter; complex or recurrent cystic nodules; or any nodule associated with palpable or ultrasonographically abnormal cervical lymph nodes. Finally, FNA should be performed on any abnormal-appearing or palpable cervical lymph nodes. The management of thyroid nodules based on FNA findings is summarized in Table 2. It can be argued that in certain circumstances the results of thyroid FNA do not change the surgical management of a thyroid nodule, and thus preoperative FNA may be unnecessary. These cases include solitary nodules in patients who have a strong family history of thyroid cancer, multiple endocrine neoplasia type II, or radiation to the head and neck. These patients when they have thyroid nodules have at least a 40% risk for thyroid cancer and frequent multifocal or bilateral disease and should undergo total thyroidectomy with or without central neck lymph node dissection. Patients who have multinodular goiter and compressive symptoms, patients who have Graves disease and a thyroid nodule, or patients who have large (greater than 4 cm) or symptomatic unilateral thyroid nodules could also be considered for total thyroidectomy or lobectomy as indicated without preoperative FNA. Finally, patients who have a solitary hyperfunctioning nodule on radioiodine scan and a suppressed TSH have an extremely low incidence of malignancy and may be considered for therapeutic thyroid lobectomy or radioiodine ablation as indicated without undergoing FNA biopsy.

Fine-needle aspiration biopsy of thyroid lesions processed by thin-layer cytology: one-year institutional experience with histologic correlation

Fine-needle aspiration biopsy (FNAB) is important for classifying thyroid lesions. Thin-layer cytology (TLC) has been adopted in thyroid cytology with encouraging results and its efficacy in diagnosing nodular lesions in a 1-year period was evaluated. All 2006 thyroid FNAB processed by TLC only in the year 2004 were examined. The 2002 and 2003 series, processed both by TLC and conventional smears (CS), were used as controls. All FNAB were classified according to previously published morphologic criteria. Surgery was performed on 311 cases: all 98 benign and 30 malignant lesions were histologically confirmed. The inadequate diagnoses resulted 11.3% in 2004, 13.3% in 2003, and 18.2% in 2002. The indeterminate diagnosis rate was 16.9% in 2004, 20.7% in 2003, and 24.8% in 2002. Sensitivity, specificity, and diagnostic accuracy values ranged from 80% to 100%. TLC is useful in reducing inadequate and indeterminate cases without decreasing the preoperative diagnostic accuracy. Ancillary techniques can be successfully applied to the stored material.

Assessing the utility of a mutational assay for B-RAF as an adjunct to conventional fine needle aspiration of the thyroid gland

Thyroid carcinoma is the most common endocrine malignancy; it is typified by a number of classical genomic insults, which tend to cluster with the discrete histologic subtypes. The most common of these is a mutation in B-RAF, which is present in approximately 44% (29% to 83%) of cases. In this review we have assessed the potential utility of a molecular test for somatically acquired mutations in B-RAF using thyroid malignancy as a model system according to 3 fundamental questions: would a test enhance our ability to distinguish benign from malignant, would a test unveil a risk factor not otherwise known, and would detecting a mutation enable a therapeutic option specific to those patients who carry the mutation?

Diagnostic accuracy of follicular variant of papillary thyroid carcinoma in fine-needle aspirates processed by ultrafast Papanicolaou stain: histologic follow-up of 125 cases

BACKGROUND

Detection of follicular variant (FV) of papillary carcinoma (PC) of the thyroid is considered difficult in cytology. Various ancillary studies have been used to increase the sensitivity in the detection of FVPC in fine-needle aspiration (FNA). We previously reported that the clear nuclei of PC became conspicuous in Ultrafast Papanicolaou (UFP)-stained smears. This study reports our experience on using this UFP-induced artifact in the detection of FVPC.

METHODS

Over an 11-year period, 5637 ultrasound-guided thyroid FNAs were performed. All samples were smeared and air-dried. Diff-Quik stain was used to assess the colloid and UFP stain was used to study the nuclei.

RESULTS

Histologic follow-up was available from 125 cases. Of the 107 aspirates with diffuse "grape-like" watery clear nuclei, histologic follow-up showed 94 PCs, 8 follicular adenomas containing atypical nuclei, and 5 nonneoplastic lesions. Of the 18 aspirates with focal clear nuclei, histologic follow-up showed 6 PCs, 8 follicular adenomas, and 4 nonneoplastic nodules. As reported previously, histologic follow-up of 147 FNAs contained follicles with normal nuclei showed 107 true follicular neoplasms, 32 hyperplastic nodules, and 8 FVPC. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy in the detection of PC were 93.6%, 94.9%, 93.6%, 94.9%, and 94.3%, respectively, when follicular adenomas containing atypical nuclei were counted as encapsulated FVPC; and 92.6%, 85.6%, 80%, 94.9%, and 88.3%, respectively, when follicular adenomas containing atypical nuclei were counted as benign.

CONCLUSION

UFP stain is one of the options to increase the sensitivity of detection of FVPC in preoperative FNA, and to triage microfollicular nodules into those that require surgery no matter how small, and those which can be followed when small.

Validation of a five-tier cytodiagnostic system for thyroid fine needle aspiration biopsies using cytohistologic correlation

OBJECTIVE

Approximately 70-80% of thyroid fine needle aspiration biopsies (FNAB) can distinguish benign from malignant thyroid nodules. However, much interpretive diagnostic difficulty arises with the remaining 20-30% of cases. These problematic thyroid aspirations have been placed in various diagnostic categories, which collectively have led to confusion and a negative impact on the clinical management of patients with thyroid nodules. We present our experience using a five-tier system, including the diagnostic terminology: benign, indeterminate, suspicious, malignant, and unsatisfactory.

DESIGN

Thyroid FNABs were diagnosed using a five-tier system from 200 consecutive patients and the subsequent surgical excisions were correlated.

MAIN OUTCOME

Overall, there was an excellent association between the five diagnostic categories and predicting benign versus neoplastic thyroid nodules (LR = 96.06, X(2) = 76.49, and phi = 0.618, df = 4, p < 0.0001). A negative cytologic diagnosis carries a negative predictive value of 92%, while an indeterminate, suspicious, and malignant cytologic diagnosis carries a positive predictive value of 50, 71, and 100% respectively. The estimated sensitivity for an indeterminate, suspicious, or malignant cytologic diagnosis varied from 70 to 89%, while the specificity increased from 57 to 92 to 100%, respectively.

CONCLUSIONS

The data presented shows that the five diagnostic categories of thyroid FNAB are excellent at distinguishing benign from neoplastic thyroid nodules. Both the indeterminate and suspicious categories, while not statistically different from each other in predicting benign from neoplasia, are statistically different from obviously benign and obviously malignant categories. These results support the need for an indeterminate and/or suspicious category.