Fine-needle aspiration biopsies in the management of indeterminate follicular and Hurthle cell thyroid lesions

Risk of malignancy in Thy3 thyroid nodules

Objective. Thyroid cancer is the most common endocrine malignancy in humans. Ultrasound guided fine needle aspiration cytology (FNAC) is now considered the best diagnostic tool for the evaluation of any thyroid nodule. Thyroid cytology is graded from Thy1 to Thy5 with Thy3 being the most challenging in diagnosis. Our aim was to identify the risk of malignancy in Thy3 cytology in our centre. This risk should be explained to the patient before taking any decision. Methods. One hundred and one patients were included in our study. All patients had Thy3 cytology on preoperative ultrasound scan guided FNAC. All patients had diagnostic hemithyroidectomy. The results from the histology were compared with the cytology findings and the rates of malignancy were identified. Results. Of the 101 patients, 17 were males and 84 females. Average age for diagnosis was 52.4±15 years of age. Patients were classified into three groups; patient who had completely benign histology (n=70), patients who had incidental finding of micro-carcinoma after diagnostic hemithyroidectomy (n=10), and patients who had thyroid macro-carcinomas (n=21). Total rate of malignancy was 30.7% when combining both the malignant and the incidental groups and 20.8% when excluding the incidental group. Conclusion. Our rates of malignancy in Thy3 cytology are similar to the literature. These rates should be explained clearly to the patient during the preoperative counselling. Future advances in biomarkers technology may help to improve the preoperative diagnostic accuracy and reduce the rate of unnecessary thyroid surgery.

Ultrasonic diagnosis for thyroid Hürthle cell tumor

OBJECTIVE

This study aims to evaluate the diagnostic value of ultrasound in thyroid Hürthle cell tumors.

METHODS

A retrospective analysis was carried out on 27 patients with thyroid Hürthle cell tumors, in terms of the size, shape, boundary, echo, aspect ratio, cystic degeneration, calcification, peripheral halo sign and blood supply of the tumor, through surgical pathological validation. Then, these were compared with postoperative pathological results.

RESULTS

The maximum diameter of the thyroid Hürthle cell tumors is between 0.6 cm and 4.6 cm. It had an oval nodule with clear boundaries, an aspect ratio > 1, and peripheral low-echo halos. Furthermore, 29.6% of tumors have even low-echo nodules without cystic changes, 48.1% and 22.1% have even medium or medium-low mixed echo nodules, and 44.4% have cystic changes in varying degrees. One nodule appeared with "micro-calcification", but pathological results confirmed that it was local collagen. Color Doppler blood flow imaging revealed that 88.8% of the nodules were surrounded with blood flow, filled with rich blood inside, and only 12.2% of the nodules had a little blood inside.

CONCLUSION

Thyroid Hürthle cell tumors have nodules with even or uneven echoes on the background of the normal echoes of the thyroid, with an aspect ratio of > 1, clear boundaries and peripheral acoustic halos. Cystic changes, colloid crystallization and fibrosis can be seen inside in varying degrees. Ultrasonography has no significant value for the differential diagnosis of benign and malignant Hürthle cell tumors.

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.

Analysis of nondiagnostic results in a large series of thyroid fine-needle aspiration cytology performed over 9 years in a single center

OBJECTIVE

Thyroid fine-needle aspiration cytology (FNAC) is the most valuable, cost-effective and accurate method for the evaluation of patients with thyroid nodules. One of its limitations is that up to 20% of results are nondiagnostic or unsatisfactory. The aim of this study was to analyze the number of thyroid FNAC specimens with nondiagnostic results obtained on an outpatient basis and how many of these had to be repeated according to their results.

STUDY DESIGN

This was a retrospective analysis of diagnostic reports of nondiagnostic thyroid FNAC specimens obtained between 1 January 2004 and 31 December 2012 which were retrieved by means of a computerized search. The FNAC results and the age and sex of the patients were collected.

RESULTS

From a total of 15,292 thyroid FNAC specimens, 6.8% (n = 1,033) corresponded to nondiagnostic cases. Eligible diagnostic reports for analysis included 877 cases (106 were repetitions of previous nondiagnostic FNAC). After an initial nondiagnostic finding for 771 FNAC smears, 29.5% (n = 225) were repeated with the following results: 43.6% insufficient, 49.3% benign, 6.2% follicular neoplasm, 0.4% suspicious for malignancy and 0.4% malignant. Twenty-two patients underwent a second repeated FNAC. Here the findings were: 36.4% insufficient, 59.1% benign, 4.5% follicular neoplasm, 0.0% suspicious for malignancy and 0.0% malignant.

CONCLUSIONS

There was a low rate of repeated FNAC among the group of nondiagnostic cases. With repeated FNAC, the rate of nondiagnostic cases and the number of results that potentially demand surgery diminish.

Thyroid nodules in pediatrics: which ones can be left alone, which ones must be investigated, when and how

Thyroid nodules are less frequent in childhood than in adulthood, but are more often malignant. Recent estimates suggest that up to 25% of thyroid nodules in children are malignant, therefore, a more aggressive approach is recommended. In this review, we suggest an approach based on a first-step clinical, laboratory, and sonographic evaluation. A history of irradiation of the neck, cranium or upper thorax, previous thyroid diseases or thyroid neoplasms in the family should alert clinicians as being associated with a greater likelihood of malignant nodules. Signs or symptoms of hyperthyroidism and dysmorphic features should be carefully considered during the physical examination. Palpable firm lymph nodes, found in some 70% of cases, are the most significant clinical finding in children with malignant nodules. Although the routine determination of calcitonin levels is not uniformly practiced, it can help recognize sporadic or familial medullary thyroid neoplasms. Blood thyroid stimulating hormone, free thyroxine, and free triiodothyronine determinations (the latter in case of symptoms of hyperthyroidism) are aimed at identifying the few hyperthyroid patients, for whom the next step should be scintiscan. Hyperthyroid patients usually disclose an increased uptake, and a diagnosis of toxic adenoma is commonly made. Cases with normal thyroid function or hypothyroidism (which is usually subclinical) should be evaluated by fine-needle aspiration biopsy (FNAB). In eu/hypo-thyroid patients, scintiscan provides poor diagnostic information and should not be routinely employed. Thyroid ultrasonography is used to select cases for FNAB. Although ultrasound cannot reliably discriminate between benign and malignant lesions, it does provide an index of suspicion. Sonographic features that increase the likelihood of malignancy are microcalcifications, lymph node alterations, nodule growth under levothyroxine treatment, and increased intranodular vascularization demonstrated by color Doppler. There is growing evidence that elastography may provide further information on nodule characteristics. FNAB is indicated in all cases with a likelihood of malignancy. FNAB has a diagnostic accuracy of approximately 90% and is used in selection of patients which require surgery. Recently, histological markers and elastography have been introduced to increase the specificity of FNAB and ultrasound, respectively. The pitfall in FNAB cytology is the follicular cytology, in which it is not possible to distinguish between adenoma and carcinoma and therefore thyroidectomy is advised.

The new molecular markers DDIT3, STT3A, ARG2 and FAM129A are not useful in diagnosing thyroid follicular tumors

Preoperative characterization of thyroid follicular lesions is challenging. Fine-needle aspiration specimens cannot differentiate follicular carcinomas from benign follicular neoplasias. Recently, promising markers have been detected using modern molecular techniques. We conducted a retrospective study to confirm the usefulness of immunohistochemical staining for the protein markers, DDIT3, STT3A (ITM1), ARG2 and FAM129A (C1orf24) in separating benign and malignant thyroid follicular lesions. Formalin-fixed, paraffin-embedded thyroid tissue from 30 in-house cases (15 follicular carcinomas and 15 follicular adenomas), as well as 8 follicular carcinomas and 21 follicular adenomas on tissue microarray slides were stained immunohistochemically for DDIT3, STT3A, ARG2 and FAM129A expression. Control tissue consisted of thyroid parenchyma adjacent to the tumors and 11 separate cases of normal thyroid parenchyma. All in-house cases of follicular adenomas, follicular carcinomas and adjacent normal thyroid tissue showed positive immunostaining with anti-DDIT3 and anti-STT3A. Anti-ARG2 and anti-FAM129A polyclonal antibodies showed positive staining in 20 and 60% of in-house follicular adenomas, and 40 and 87% of in-house follicular carcinomas, respectively. Monoclonal anti-FAM129A demonstrated positive staining in 13 and 33% of in-house follicular adenomas and follicular carcinomas, respectively. Polyclonal anti-DDIT3, -STT3A and -FAM129A antibodies showed positive staining in all tissue microarray slides of follicular carcinoma and in 76, 85 and 81% of the follicular adenomas, respectively. Monoclonal anti-STT3A stained 81% of the follicular adenoma cores. Anti-ARG2 stained positive in 13% of follicular carcinomas and 10% of follicular adenomas on the tissue microarray slides. In conclusion, DDIT3, STT3A, ARG2 and FAM129A immunohistochemistry does not appear to be useful in the diagnosis of thyroid follicular neoplasias, as they do not reliably distinguish follicular thyroid carcinoma from follicular thyroid adenoma.

Metastases to the thyroid: a review of the literature from the last decade

BACKGROUND

Although clinically evident metastases of nonthyroid malignancies (NTMs) to the thyroid gland are uncommon, it is important to suspect them in patients who present with a new thyroid mass and a history, however far back, of prior malignancy. In fact, metastases from NTMs to the thyroid gland have been reported in 1.4%-3% of all patients who have surgery for suspected cancer in the thyroid gland. Here we review the literature over the last decade regarding this topic.

SUMMARY

Based on recent literature, the most common NTMs that metastasize to the thyroid gland are renal cell (48.1%), colorectal (10.4%), lung (8.3%), and breast carcinoma (7.8%), and sarcoma (4.0%). Metastases of NTMs to the thyroid are more common in women than men (female to male ratio=1.4 to 1) and in nodular thyroid glands (44.2%). The mean and median intervals between diagnosing NTMs and their metastases to thyroid gland are 69.9 and 53 months, respectively. In 20% of cases the diagnosis of the NTM and its metastases to the thyroid was synchronous. Recent reports indicate that there is a higher frequency of sarcoma metastasizing to the thyroid gland than reported in prior years. Fine-needle aspiration biopsy (FNAB) of thyroid masses is useful in diagnosis of thyroid metastases. However, this requires information about the NTM so that the proper antibodies can be used for immunohistochemical analysis; therefore it is of lesser utility if the NTM is occult. In patients with preexisting thyroid pathology the FNAB diagnosis can be more difficult due to more than one lesion being present.

CONCLUSIONS

It is important to keep in mind that the thyroid gland can be a site of metastases for a variety of tumors when evaluating a thyroid nodule, especially in a patient with a prior history of malignancy. In patients with thyroid lesions and a history of malignant disease, regardless of time elapsed since the initial diagnosis of the primary neoplasm, disease recurrence or progression of malignancy must be considered until proven otherwise.

The significance of hurthle cells in thyroid disease

Hürthle cells (HCs) and HC change, along with the frequently employed synonyms "oncocytes/oncocytic change" or "oxyphils/oxyphilic change," are not infrequently described on fine-needle aspiration biopsy (FNAB) reports of thyroid lesions. The description of HCs on FNAB reports may cause significant concern to the clinician; however, placing the finding in the appropriate clinical context may alleviate some anxiety. Not all oxyphilic cells are true HCs and not every aspirate containing HCs is or should be considered equivalent to an HC neoplasm (HCN). There are many benign thyroid lesions associated with HCs or HC change. For clinicians, it may be difficult to discern the significance of these findings and to determine an appropriate course of action. A skilled and experienced cytopathologist is invaluable in discriminating the subtle features that distinguish these lesions from those warranting a more aggressive approach. The diagnosis of HC carcinoma relies on histopathologic scrutiny and evidence of capsular and/or vascular invasion or metastasis to lymph nodes or distant organs. Many investigators have sought clinical, radiographic, cytological, genetic, and other factors to attempt to discriminate preoperatively between benign and malignant HCNs. To date, none have been definitively proven to be reliable. For now, because of the inability to determine the benign or malignant nature of such neoplasms based on cytology alone, a surgical approach is warranted.

Thy3 cytology: what to do next?

INTRODUCTION

Cytological analysis of thyroid fine needle aspiration (FNA) is aided by the 'Thy' classification. However, there is often confusion surrounding the management of patients with a Thy3 classification. A subdivision of Thy3 has been created to help reduce this dilemma but its use within the UK appears to by infrequent. This paper analyses the management of patients with Thy3 cytology from FNA of a thyroid nodule in a UK case series and reviews the relevant literature. It also describes the results of a survey of selected UK ENT departments on the use of the Thy3 classification and its subdivisions.

PATIENTS AND METHODS

A retrospective analysis of a case series of patients was undertaken. In addition, a telephone survey of local/regional pathology departments was conducted to assess the utilisation of the Thy classification and to assess the awareness and usage of the Thy3 subdivisions.

RESULTS

A total of 39 Thy3 results (11 males, 28 females) were identified from 2007 to 2009. Of these, 24 patients went on to have surgery, 8 had a further FNA, 2 had a Tru-cut biopsy and 5 were lost to follow-up. Eleven (28.2%) patients were subsequently diagnosed with a thyroid malignancy. The survey identified that none of the departments had adopted the Thy3 subclassifications and only 40% were aware of them.

CONCLUSIONS

Thy3 results from thyroid FNA have a significant risk of malignancy but there remains confusion surrounding their management. This district general hospital has adopted and recommends the use of the Thy3 (i) and Thy3 (ii) subdivisions in order to assist decision-making and avoid delays in treatment or unnecessary surgery.

The predictive value of dominant nodules and the management of indeterminate group in multinodular goiter

The objectives of this study were to determine the predictive value of dominant nodules (DNs) in multinodular goiters (MNGs), and to stratify the risk of malignancy within the indeterminate category. The study design was retrospective study of patients with MNG. A total of 140 patients were reviewed. Fine needle aspiration biopsy (FNAB) findings for all DNs were categorized into four groups: (1) benign, (2) positive or suspicious for malignancy, (3) indeterminate, and (4) non-diagnostic. All FNAB specimens of the indeterminate group were also evaluated for the presence of Hurthle cell metaplasia and were categorized according to the presence of cytological atypia. Cytohistological comparison was then performed. Mean number and diameter of the DNs were 1.45 and 25.6 mm, respectively. Based on final histopathology, 22.14% of the patients had thyroid malignancy and 74.2% of thyroid carcinomas were located in DNs. The number of DNs was significantly larger in malignant thyroid glands than in benign ones. In total, 22.6% of the indeterminate FNABs were malignant. FNABs of the indeterminate group that included atypical cells had a statistically significant higher incidence of malignancy. The presence of Hurthle cells was not statistically different in malignant and benign nodules upon final histological diagnosis. In conclusion, FNAB of only DNs in MNG could determine thyroid malignancy in 75% of patients. The DN number might be required for the predictive value of malignancy. A subclassification of the indeterminate group, based on the presence or absence of cytological atypia, is necessary to better assess the risk of malignancy.

Predictors of Malignancy in Patients with a Thyroid Nodule That Contains Hürthle Cells

Objective. Fine needle aspiration cytology of a thyroid nodule with Hürthle cells can be present in both benign and malignant diseases of the thyroid. The aim of this study was to identify the factors that predict malignancy in patients who underwent thyroidectomy with a preoperative fine needle aspiration cytology that contains a predominance of Hürthle cells.

Study Design. Retrospective data collection.

Setting. Tertiary referral center.

Subjects and Methods. Medical records of 70 consecutive patients were reviewed between March 2005 and August 2010. Predictive factors, as well as age, gender, preoperative serum thyroid-stimulating hormone level, the microscopic findings of fine needle aspiration, ultrasonographic appearance, and size and number of nodules in the pathology report, were correlated with final histopathologic diagnosis of benign or malignant disease.

Results. Patients’ final pathology showed that 21 patients (30%) had malignant disease, of whom 15 patients (71.4%) had papillary carcinoma and 6 patients (28.6%) had Hürthle cell carcinoma. Forty-nine (70%) patients had benign disease (hyperplastic/adenomatoid nodule in 24 patients, Hashimoto thyroiditis in 18 patients, Hürthle cell adenoma in 5 patients, and follicular adenoma in 2 patients). The rate of malignancy was higher in male patients (42.9% vs 28.6%), with nodules measuring ≥2 cm (36.7% vs 25.0%), the presence of a solitary nodule (34.3% vs 27.7%), and the presence of metaplasia in fine needle aspiration (36.4% vs 27.1%), although none was found to be significant ( P > .05).

Conclusion. Thyroid nodules that are reported in cytology as Hürthle cell lesions require surgery to differentiate benign from malignant disease.

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.

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.