Thyroid follicular neoplasms diagnosed by high-resolution ultrasonography with fine needle aspiration cytology

The possibilities of ultrasound imaging in the diagnosis of follicular neoplasia of the thyroid gland

Thyroid cancer is the most common cancer of the endocrine system. The diagnosis of thyroid cancer has taken a step forward due to the introduction of fine-needle biopsy of the thyroid gland with subsequent evaluation of cytological material using the Bethesda system. One category of this classification traditionally remains a gray area of diagnosis. The detection of a follicular tumor in the cytological material (category IV according to Bethesda) does not allow one to reliably classify the neoplasia as benign or malignant and requires surgical intervention. The traditional informative and widely used method for diagnosing thyroid tumors is ultrasound. However, the sensitivity and specificity of the method varies over a wide range. This review analyzes the literature on the possibilities of ultrasound diagnostics in assessing the malignant potential of follicular tumors of the thyroid gland.

Differentiate Thyroid Follicular Adenoma from Carcinoma with Combined Ultrasound Radiomics Features and Clinical Ultrasound Features

Noninvasive differentiating thyroid follicular adenoma from carcinoma preoperatively is of great clinical value to decrease the risks resulted from excessive surgery for patients with follicular neoplasm. The purpose of this study is to investigate the accuracy of ultrasound radiomics features integrating with ultrasound features in the differentiation between thyroid follicular carcinoma and adenoma. A total of 129 patients diagnosed as thyroid follicular neoplasm with pathologically confirmed follicular adenoma and carcinoma were enrolled and analyzed retrospectively. Radiomics features were extracted from preoperative ultrasound images with manually contoured targets. Ultrasound features and clinical parameters were also obtained from electronic medical records. Radiomics signature, combined model integrating radiomics features, ultrasound features, and clinical parameters were constructed and validated to differentiate the follicular carcinoma from adenoma. A total of 23 optimal features were selected from 449 extracted radiomics features. Clinical and ultrasound parameters of sex (p = 0.003), interior structure (p = 0.035), edge (p = 0.02), platelets (p = 0.007), and creatinine (p = 0.001) were associated with the differentiation between benign and malignant follicular neoplasm. The values of area under curves (AUCs) of the radiomics signature, clinical model, and combined model were 0.772 (95% CI: 0.707-0.838), 0.792 (95% CI: 0.715-0.869), and 0.861 (95% CI: 0.775-0.909), respectively. A final corrected AUC of 0.844 was achieved for the combined model after internal validation. Radiomics features from ultrasound images combined with ultrasound features and clinical factors are feasible to differentiate thyroid follicular carcinoma from adenoma noninvasive before operation to decrease the unnecessary of diagnostic thyroidectomy for patients with benign follicular adenoma.

Sonographic Features Differentiating Follicular Thyroid Cancer from Follicular Adenoma-A Meta-Analysis

Simple Summary

The risk of thyroid malignancy assessment may include certain ultrasound features. The analysis is lacking for the differentiation of follicular thyroid adenomas and cancers (FTAs and FTCs). Our meta-analysis aimed to identify sonographic features suggesting malignancy in the case of follicular lesions, potentially differentiating FTA and FTC. Based on twenty studies describing sonographic features of 10,215 nodules, we found that the most crucial feature associated with an increased risk of FTC were tumor protrusion (odds ratios—OR = 10.19), microcalcifications or mixed type of calcifications: 6.09, irregular margins: 5.11, marked hypoechogenicity: 4.59, and irregular shape: 3.6.

Abstract

Certain ultrasound features are associated with an increased risk of thyroid malignancy. However, they were studied mainly in papillary thyroid cancers (PTCs); these results cannot be simply extrapolated for the differentiation of follicular thyroid adenomas and cancers (FTAs and FTCs). The aim of our study was to perform a meta-analysis to identify sonographic features suggesting malignancy in the case of follicular lesions, potentially differentiating FTA and FTC. We searched thirteen databases from January 2006 to December 2020 to find all relevant, full-text journal articles written in English. Analyses assessed the accuracy of malignancy detection in case of follicular lesions, potentially differentiating FTA and FTC included the odds ratio (OR), sensitivity, specificity, positive and negative predictive values. A random-effects model was used to summarize collected data. Twenty studies describing sonographic features of 10,215 nodules met the inclusion criteria. The highest overall ORs to increase the risk of malignancy were calculated for tumor protrusion (OR = 10.19; 95% confidence interval: 2.62–39.71), microcalcifications or mixed type of calcifications (coexisting micro and macrocalcifications): 6.09 (3.22–11.50), irregular margins: 5.11 (2.90–8.99), marked hypoechogenicity: 4.59 (3.23–6.54), and irregular shape: 3.6 (1.19–10.92). The most crucial feature associated with an increased risk of FTC is capsule protrusion, followed by the presence of calcifications, irrespectively of their type.

Ultrasound-guided fine-needle aspiration or core needle biopsy for diagnosing follicular thyroid carcinoma?

OBJECTIVE

We evaluated the preoperative diagnostic values of ultrasound (US), fine-needle aspiration (FNA) and core needle biopsy (CNB) leading to surgery in patients with FTC.

METHODS

From October 1994 to July 2016, 298 patients with FTC who had preoperative US images and underwent US-guided FNA or CNB and surgery were included in this study. We evaluated the results of preoperative FNA or CNB based on the Bethesda system and the US findings according to the Korean thyroid imaging reporting and data system (K-TIRADS).

RESULTS

Predominant US features of FTC showed solid, hypo- or iso-echogenicity, oval smooth margin and halo with no calcification. Based on K-TIRADS, 140 (47.0%) patients with FTC were categorized as low suspicion, 133 (44.63%) as intermediate suspicion and 25 (8.4%) as high suspicion at US. Considering only FNA cytology (n = 230), 6.9% were revealed as Bethesda class I, 16.1% as class II, 37.0% as class III, 29.1% as class IV and 10.9% as class V. Considering the 68 cases with CNB results, 2.9% were revealed as class I, 4.4% as class II, 20.6% as class III and 72.1% as class IV. Despite multiple FNAs, 16.7% of the 84 patients with FTC still obtained Bethesda class I or class II. CNB results in patients with FTC had a significantly higher rate of Bethesda class IV compared to the FNA results (P < .001). FTCs with distant metastasis exhibited a significantly higher rate of Bethesda classes IV and V compared to those without distant metastasis (P = .004).

CONCLUSION

Surgery for FTC is deferred only with preoperative US and FNA. CNB in patients with FTC can lead to surgery better than FNA. Therefore, if the US feature is characteristic and a serially growing large nodule is suspected, the first attempt of CNB may be helpful in selecting a surgical candidate.

Utility of Routine Frozen Section of Thyroid Nodules Classified as Follicular Neoplasm

OBJECTIVES

To evaluate the diagnostic performance of frozen section in thyroid nodules classified as follicular neoplasm.

METHODS

A diagnostic test meta-analysis was designed. Studies that assessed frozen section in patients with thyroid nodules and a fine-needle aspiration biopsy result of Bethesda IV were selected. The outcomes measured were the number of false- and true-positive and -negative results. We used the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) instrument for methodological quality assessment and a bivariate mixed-effects regression framework and a likelihood-based estimation of the exact binomial approach.

RESULTS

Forty-six studies from 1991 to 2018 were included. Most studies had moderate methodological quality. The overall sensitivity and specificity were 43% (95% confidence internal [CI], 0.34-0.53) and 100% (95% CI, 0.99-1.00), respectively. The hierarchic summary receiver operating characteristic curve showed an area under the curve of 0.91 (95% CI, 0.80-0.97).

CONCLUSIONS

Frozen section demonstrates moderate diagnostic performance in patients with follicular neoplasm, and its utility for making intraoperative decisions is limited. Its routine use should be discouraged.

Prediction of follicular thyroid carcinoma associated with distant metastasis in the preoperative and postoperative model

BACKGROUND

Only clinicopathological findings are reported for predicting follicular thyroid carcinoma (FTC) associated with distant metastasis, and preoperative ultrasound (US) findings are unknown.

METHODS

Associations between distant metastases of FTC and predicting factors were evaluated by using logistic regression analysis in the preoperative and postoperative models.

RESULTS

Distant metastasis was present in 37 (11.5%) of the 321 patients with FTC. In the preoperative model, independent predictors of distant metastasis were age, marked hypoechogenicity, nodule-in-nodule appearance, and rim calcification on US. Postoperative predictors were marked hypoechogenicity, rim calcification, and widely invasive histology. Sensitivities, specificities, and the area under the curves for predicting distant metastasis were 86.5%, 80.3%, and 0.889 on preoperative status and 86.5%, 78.5%, and 0.908 on postoperative status. Although not statistically significant, all four patients with gross extrathyroidal extension had metastasis.

CONCLUSION

Age, ultrasound features, and widely invasive histology allow preoperative and postoperative prediction of FTC associated with distant metastasis.

Subclassification of Bethesda Atypical and Follicular Neoplasm Categories According to Nuclear and Architectural Atypia Improves Discrimination of Thyroid Malignancy Risk

BACKGROUND

Although The Bethesda System for Reporting Thyroid Cytopathology has provided clinicians with a standardized classification scheme for the diagnosis of thyroid fine-needle aspiration cytology (FNAC) specimens, the indeterminate categories of Bethesda III (B3)-atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS)-and Bethesda IV (B4)-follicular neoplasm/suspicious for follicular neoplasm (FN/SFN)-continue to pose challenges with regards to ideal diagnostic and therapeutic management. Having previously demonstrated the presence of nuclear atypia as a high-risk subgroup in B3, the objective of this study was to evaluate the malignancy rates in the B4 subgroup with nuclear atypia.

METHODS

A retrospective review of all thyroid FNACs diagnosed as B4 (FN/SFN) between 2008 and 2015 was conducted at a tertiary referral center in Singapore. Data on patient demographics, sonographic features, and final histological diagnosis were collected. This was compared to data from a previous analysis on all nodules diagnosed as B3 (AUS/FLUS) over a similar period.

RESULTS

A total of 137/309 (44.3%) and 88/111 (79.3%) FNACs diagnosed as B3 and B4, respectively, underwent surgical excision yielding final histopathological diagnoses. The malignancy rate of B4 was 31/88 (35.2%) compared to B3, which was 37/137 (27.0%). Subclassification based on the presence of architectural versus nuclear atypia showed significantly higher malignancy rates in B4 nodules with nuclear atypia (21.8% vs. 57.6%; p < 0.01). These findings corroborate previous results within the B3 category (malignancy rate of 14.7% vs. 36.8%; p < 0.01). The only sonographic features predictive of malignancy were the presence of macrocalcifications in B4 compared to irregularity of margins in B3.

CONCLUSION

The presence of nuclear atypia identifies subgroups with significant differential malignancy risks within both the B3 and B4 categories. This supports the notion that subclassification is a useful risk stratification tool that can guide diagnostic and therapeutic management of indeterminate thyroid nodules with heterogenous risk profiles.

Thyroid Cancer: Ultrasound Imaging and Fine-Needle Aspiration Biopsy

Ultrasound is critical in detection, diagnosis, and management of thyroid nodules. Ultrasound detection of regional nodal metastatic disease is based on abnormal nodal morphology rather than size and is critical to initial surgical and long-term management of thyroid cancer. Fine-needle aspiration biopsy is the gold standard for malignancy diagnosis in thyroid cancer. Thyroglobulin assay of nodal aspirates improves accuracy in diagnosis of metastases. Reporting lexicons assign risk levels to thyroid nodules with the goal of improving and standardizing patient management. Surveillance ultrasound in papillary microcarcinomas is being evaluated and compared with surgical management.

"Nodule in Nodule" on Thyroid Ultrasonography: Possibility of Follicular Carcinoma Transformed from Benign Thyroid Tumor

BACKGROUND

It is generally considered impossible to differentiate follicular carcinomas from follicular adenomas by means of ultrasonography or cytology before surgery. Therefore, follicular carcinoma is histopathologically diagnosed by verifying capsular and/or vascular invasion after surgery. However, ultrasonography may play an important role in diagnosing follicular carcinoma preoperatively in a small number of cases.

CASE DESCRIPTION

Four cases of follicular carcinoma or follicular neoplasm that transformed from a benign thyroid tumor and demonstrated a "nodule in nodule" appearance on ultrasonography are presented in this report. Characteristic ultrasound features of such patients are: (1) a "nodule in nodule" appearance, (2) a well-defined boundary line between the nodules, and (3) separate distribution of blood signals within each nodule.

CONCLUSION

A small number of patients with follicular carcinomas or follicular neoplasms may present with a "nodule in nodule" appearance on ultrasonography. It was suggested a long time ago that follicular carcinomas may develop from benign thyroid tumors. The fact that follicular carcinomas appear within benign tumors may be evidence of thyroid tumorigenesis.

Papillary thyroid carcinoma risk factors in the Yunnan plateau of southwestern China

Objective

This study investigated clinical and pathological characteristics and risk factors in papillary thyroid carcinoma (PTC) patients’ native to Yunnan plateau in southwestern China.

Methods

Clinical data from 1,198 patients diagnosed with PTC (n=578) and control subjects (n=620) with benign thyroid disease (ie, thyroid nodule disease, benign thyroid diseases [BTD]) in Yunnan province were analyzed retrospectively.

Results

The mean patient age was lower for PTC than for BTD. Positive ratios of thyroid peroxidase antibody, thyroglobulin antibody (TGAb), and thyrotrophin receptor antibody (TRAb) were higher in PTC than in BTD patients. The ratio of PTC coexisting with Hashimoto’s thyroiditis (HT) or with lymphocytic thyroiditis was higher than that of BTD. The number of patients whose age at menarche was ≤13 years, who had given birth to less than or equal to two children, or who were in premenopause were higher in the PTC than in the BTD group. Multivariate conditional logistic regression analyses revealed that age >45 years, nodal size >1 cm, and elevated TG levels were protective factors against PTC. Abnormally elevated TGAb and TRAb levels were independent risk factors for PTC in females.

Conclusion

HT was not an independent risk factor for but was associated with PTC. TRAb is a risk factor for PTC in individuals living in the Yunnan plateau, but not for those in the plains region.

'Suspicious for a follicular neoplasm' before and after the Bethesda System for Reporting Thyroid Cytopathology: impact of standardized terminology

BACKGROUND

The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) standardized the terminology for indeterminate diagnoses, but the performance of the indeterminate categories before and after TBSRTC has not been compared. This study evaluates the 'suspicious for a follicular or Hürthle cell neoplasm' (SFN/HCN) category before and after the introduction of TBSRTC at a single institution and in a meta-analysis of the literature.

METHODS

A meta-analysis compiled findings from publications on SFN/HCN or similar diagnoses before and after the introduction of TBSRTC. The pathology database at our institution identified all SFN/HCN or similar diagnoses in the 8 years surrounding the introduction of TBSRTC, and those cases were correlated with the surgical follow-up.

RESULTS

In the meta-analysis, the fraction of cases called SFN/HCN or the equivalent increased from 6.1 to 7.4% (p = 0.0002); the surgical follow-up rate increased from 55 to 61% (p < 0.00001), and the histological malignancy rate among the cases that were resected increased from 22 to 28% (p = 0.03) after TBSRTC. In our institutional experience, the introduction of TBSRTC did not coincide with any significant changes.

CONCLUSION

Standardized terminology clearly coincided with increases in follow-up and the malignancy rate of SFN/HCN. A change in the same statistics was not seen in our institutional experience.

Thyroid follicular neoplasm: analysis by fine needle aspiration cytology, frozen section, and histopathology

We performed a retrospective analysis of follicular neoplasm data obtained from frozen section examinations of thyroid nodules. A total of 5,660 patients underwent preoperative neck ultrasonography and fine-needle aspiration cytology (FNAC), surgical treatment, and follow-up at a medical institute. Patients with papillary thyroid microcarcinoma were excluded from this study. In 971 cases, frozen section examination was performed during the surgical treatment of follicular neoplasm that was diagnosed via FNAC. Thyroid malignancies were histologically confirmed in 25.1% of cases (244/971). Among the patients with papillary thyroid carcinoma, 45 were diagnosed with the follicular variant of papillary thyroid carcinomas (27.4%). The diagnostic sensitivity of frozen section for the nonfollicular variant of papillary thyroid carcinoma was better than that for the follicular variant of papillary thyroid carcinoma (89.1% versus 78.9%; P = 0.1023). For 12 cases the diagnosis was atypical follicular adenomas. The diagnostic accuracy of frozen section in cases of follicular neoplasm was 76.9% with a sensitivity of 84.8% and a specificity of 98.9%. In conclusion, our analysis revealed high rates of accuracy when using frozen tissue sections for early diagnosis and treatment of follicular neoplasm; thus, an early decision to extent of surgery prevents a risky follow-up surgery.

The diagnostic accuracy of the immunocytochemical markers in the pre-operative evaluation of follicular thyroid lesions

Aim of the study was to consider the diagnostic accuracy of galectine-3 (GAL3) in the pre-operative cytological evaluation of follicular lesions.

MATERIALS AND METHODS

We retrospectively evaluated 100 patients suffering from thyroid nodular disease submitted to thyroidectomy from 2006 to 2007 in our Institution. Before surgery all patients underwent fine needle aspiration biopsy. The immunocytochemical analysis was performed on fine needle aspiration specimens using species-specific monoclonal antibodies and a biotin-free detection system. Based on preoperative cytological reports, 40 patients had pre-operative malignant results, and 60 patients (46 females and 14 males) showed follicular lesions. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of GAL3 was evaluated.

STATISTICAL ANALYSIS

Chi-square test was used to compare frequencies of GAL3 expression between the different hystopathological groups.

RESULTS

GAL3 proved to have 55% sensitivity, 100% specificity, 70% negative predictive value, and 78% diagnostic accuracy. The GAL3 expression in neoplastic and benign lesions was significantly different (GAL3+ in 16 out of 29 neoplastic lesions, GAL3+ 0 out of 31 benign lesions, p<0.01). Even comparing the GAL3 positivity between the follicular adenomas (0 GAL3+ out of 20) and the group of follicular carcinomas (5 GAL3+ out of 6), we found a statistically significant difference (p<0.01).

CONCLUSIONS

Based on the data from our experience, the patients with a cytological diagnosis of GAL3 positive follicular neoformation should be referred for surgery without any further immunocytological testing.

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.

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.

Follicular thyroid carcinoma: From diagnosis to treatment

Unusual presentations with bone, lung or soft tissue metastases in initial diagnosis of follicular thyroid carcinoma have been reported occasionally. This implies how difficult it is to diagnosis this type of cancer at the pre-operative or intra-operative stage of treatment. Fine needle aspiration cytology has been shown to be an ineffective method for diagnosing vascular or capsule invasion of follicular thyroid cancer. Multiple frozen sections, usually 5 to 12 depending on the size of the tumor, can achieve a diagnostic accuracy of 98%. Clinical application of various gene expressions in thyroid follicular tumors by needle aspiration using in situ hybridization requires further investigation. Although radioactive iodide (131I) has been used as the standard treatment for follicular thyroid carcinoma with distant metastases, the effectiveness of 131I treatment for follicular thyroid carcinoma depends on the differentiation of cancer cells. The possibility of 131I for thyroid remnant ablation replacing a secondary operation for follicular thyroid carcinoma has been debated. Recent studies applied more expressions of sodium iodide symporters to attain the effect of 131I treatment and slow the proliferation of thyroid cancer cell which, in turn, slows the progression of follicular carcinoma. Consensus for the surgical procedures for the specific prognostic risks for follicular thyroid carcinoma is needed. Dedifferentiated, anti-angiogenic, or gene therapies for follicular thyroid cancer with distant metastases or anaplastic transformation comprise the principal directions in future research for this cancer.

Telomerase activity in fine needle aspiration biopsy samples: Application to diagnosis of human thyroid carcinoma

BACKGROUND

The diagnosis of thyroid follicular carcinoma by fine needle aspiration biopsy is a well known problem in thyroid pathology.

METHODS

We evaluated telomerase activity (TA) in 85 fine needle aspiration biopsy (FNAB) samples from patients with thyroid nodules. Surgery samples from patients with tumor or follicular adenomas were also analyzed.

RESULTS

Twenty of the FNAB samples corresponded to carcinomas and were positive to telomerase assay (TA >10 Units). Among them, 4 follicular carcinomas and 1 papillary carcinoma were labeled as indeterminate by FNAB cytological examination. Four percent false positive cases and no false negative cases for TA in FNABs were reported. FNAB samples from follicular adenomas were diagnosed as indeterminate by cytological examination, but they showed no detectable TA. Tumor tissues from patients with follicular or papillary thyroid carcinomas presented TA >10 Units, whereas follicular adenoma tissues (benign nodules) showed no TA.

CONCLUSION

Our results showed a good correlation between TA in FNAB samples and tumor/nodule thyroid tissue. This suggested that use of TA as a biological marker of malignancy might be a useful tool in the diagnosis of follicular thyroid carcinomas or follicular thyroid adenomas using FNAB samples.

Ultrasound of thyroid cancer

The management of thyroid nodules is multi-disciplinary and involves head and neck surgeons, pathologists and radiologists. Ultrasound is easy to perform, widely available, does not involve ionizing radiation and is readily combined with fine needle aspiration cytology (FNAC). It is therefore an ideal investigation of choice for evaluating thyroid nodules. It evaluates specific features that help in identifying the nature of the nodule and FNAC helps in diagnostic accuracy. In addition, following treatment for thyroid cancer ultrasound provides a safe tool for disease surveillance. This paper discusses the role of ultrasound in the management of patients with thyroid cancer.

Thyroid cancer in the thyroid nodules evaluated by ultrasonography and fine-needle aspiration cytology

Thyroid nodule is common disorder in endocrine clinics. In Taiwan, thyroid ultrasonography with fine-needle aspiration cytology (FNAC) is the first-line examination procedure. Data in large series on the incidence of thyroid malignancy presenting with thyroid nodules are lacking in this area. To determine the incidence of malignancy in thyroid nodules and compare the results with other populations, this investigation retrospectively reviewed 21,748 subjects who were examined in one medical center from January 1986 to December 1999. All patients underwent thyroid ultrasonography studies using a real-time ultrasonographic machine and a 10-MHz transducer. Fine-needle aspirations were made in the suspected thyroid nodule and stained using the Romanowsky- based method developed by Liu. By the end of 2002, some 3629 patients (16.7%) had thyroid nodules after surgical treatment. This group comprised 3011 women with a mean age of 41.5 +/- 13.9 years, and 618 men with a mean age of 45.7 +/- 14.9 years. Of patients undergoing surgical treatment, 2761 (76.1%) patients were diagnosed with benign nodules, 858 (23.6%) with malignant nodules, and 10 (0.3%) with atypical adenoma (7 follicular and 3 Hürthle cells). The percentages of thyroid malignancy in each age group revealed two peaks in both genders, namely in patients aged 20 to 29 years and in elderly patients (aged over 65 years). The peak age for thyroid malignancy in both genders was 41 to 60 years (male) and 21 to 40 years (female). The highest ratio of malignancy occurred in the elderly group (37.2%) receiving surgical treatment. In young patients (below 19 years) the percentage of malignancy was no greater than for the whole age group (20.2% versus 25.6%). Anaplastic and metastatic cancers affecting the thyroid were the main subjects in the age group. The present results demonstrated a younger distribution for well-differentiated thyroid cancer, particularly papillary thyroid carcinoma, compared to previous studies. This outcome may have resulted from the routine application of ultrasonography with FNAC in assessing the thyroid nodules, possibly helping to achieve more timely detection. The incidence of thyroid malignancy in young patients was no higher than in adults. Early detection of thyroid malignancy may be the main reason for this phenomenon. Male subjects with thyroid nodules displayed a higher incidence of this malignancy than females. Aging subjects with thyroid nodules suffered a higher rate of malignancy and were poorly differentiated. In conclusion, this retrospective large-series study demonstrated that 3.9% (858/21,748 cases) of patients with thyroid nodules showed histopathologically proven malignancy. Thyroid cancer detected by ultrasonography with FNAC occurred an average of 10 years younger than in prior studies.

Reporting thyroid fine-needle aspiration: Literature review and a proposal

Reporting schemes for thyroid fine-needle aspirations in the literature were reviewed and classified according to the number of categories in the scheme and the significance of each category. The sensitivity, specificity, and positive predictive and negative values were determined for each scheme, if possible. A reporting scheme based on the probability of finding carcinoma on histology is proposed.

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.

Risk of Malignancy in Follicular Neoplasms without Nuclear Atypia: Statistical Analysis of 397 Thyroidectomies

OBJECTIVE

To determine how to triage patients with a follicular neoplasm (FN), without nuclear atypia reported by fine-needle aspiration, on the basis of risk factors.

METHODS

The age, sex, tumor size, and cell type of 397 patients who underwent thyroidectomy for follicular carcinoma (FC) or follicular adenoma between 1991 and 2001 were analyzed statistically. The likelihood ratio and probability of FC for various combinations of tumor size, sex, and cell type were estimated with use of Bayes' theorem.

RESULTS

FC was significantly associated with tumor size >2.1 cm (P = 0.048), male sex (P = 0.0007), and Hürthle cell type (P<0.0001). The mean size of minimally invasive FC was significantly smaller (2.9 cm versus 4.8 cm; P = 0.004) and the mean patient age was significantly younger (47.6 years versus 61.0 years; P = 0.003) than for widely invasive FC. The lowest probability (0.31%) for FC was in female patients with a small (< or = 2.1 cm) micro-follicular FN reported by a cytopathology practice with 10% accuracy of true FN at surgical intervention, whereas the highest probability (29.5%) for FC was in male patients with a large (>2.1 cm) Hürthle cell neoplasm reported by a cytopathology practice with 70% accuracy of true FN at surgical intervention.

CONCLUSION

Although an estimate of probability for FC based on age, sex, thyroid nodule size, and cell type is provided in this study for patients diagnosed with FN without nuclear atypia on fine-needle aspiration, the variability of the accuracy in cytopathology practice makes it difficult to change the current treatment paradigm, which requires carefully planned prospective studies with long-term follow-up.

Should cytopathologists stop reporting follicular neoplasms on fine-needle aspiration of the thyroid?

BACKGROUND

As the consequence of the decreasing incidence of follicular thyroid carcinoma (FC), one wonders whether cytopathologists should stop reporting follicular neoplasms in fine-needle aspiration (FNA) of the thyroid to minimize unnecessary thyroidectomies, if the follicular variant of papillary carcinoma (FVPC) has been excluded.

METHODS

Over a 6-year-period, 2667 ultrasound-guided FNAs of the thyroid were performed at our practice. A total of 246 nodules (9.2%) were reported as follicular neoplasms, using abundant blood as the diagnostic clue. All FNA specimens were prepared and reported by one cytopathologist and the final pathology was reported by surgical pathologists in various hospitals in New York City.

RESULTS

The histologic follow-up was available for 147 cases and showed 5 cases of widely invasive FC (3.4%), 10 cases of minimally invasive FC (6.8%), 8 cases of FVPC (5.4%), 92 cases of follicular adenoma (62.6%), and 32 cases of nonneoplastic nodules (21.8%).

CONCLUSIONS

FVPC cannot be excluded completely from follicular neoplasms by FNA because of the patchy distribution of papillary carcinoma nuclei in the encapsulated variant. Widely invasive FC still exists and may cause considerable morbidity in patients as young as the third decade of life. It is the opinion of the authors that cytopathologists should continue reporting follicular neoplasms in FNA of the thyroid.

Human telomerase reverse transcriptase (hTERT) gene expression in FNA samples from thyroid neoplasms

Identifying a tumor marker that can help distinguish benign from malignant thyroid tumors is crucial, because up to 30% of thyroid fine-needle aspirations (FNA) are diagnosed as 'suspicious' or follicular neoplasm for malignancy. Recently, the detection of human telomerase reverse transcriptase (hTERT) gene expression in thyroid FNA samples has been identified as a promising diagnostic marker in distinguishing benign and malignant thyroid tumors. Twenty-seven FNA samples from thyroid tumors that were suspected to be malignant were collected preoperatively, hTERT gene expression was examined by reverse transcriptase-polymerase chain reaction (RT-PCR), and the cytological and histological results were compared. The results demonstrated that 13 (92.8%) of 14 thyroid carcinomas, including eight of eight papillary, three of four follicular, and two of two Hürthle cell thyroid carcinomas have corresponding FNA samples that were positive for hTERT. Meanwhile, eight (61.5%) of 13 benign thyroid nodules, including three of six nodular goiter, two of two Graves' disease, two of two Hürthle cell adenomas, and one of three follicular adenomas were positive for hTERT. In conclusion, hTERT was more prevalent in malignant thyroid FNA samples than in the benign thyroid FNA samples. Notably, the extent of the differences in hTERT expression between benign and malignant follicular thyroid tumors require further investigation. Moreover, further information including semi-quantitative real-time RT-PCR, is required to verify whether hTERT mRNA expression could serve as an adjunctive molecular marker for the preoperative diagnosis of thyroid malignancies.

Computer-assisted cell morphometry and ploidy analysis in the assessment of thyroid follicular neoplasms

Conventional cytology cannot discriminate between benign and malignant follicular neoplasms. Our study evaluated the diagnostic role of computer-assisted image analysis in the presurgical assessment of thyroid follicular neoplasms. Fifty-eight patients (14 males, 44 females, age range, 45-75 years) who underwent surgery for cytologic diagnosis of thyroid follicular neoplasm were studied. All patients were first evaluated on clinical grounds and assigned a high/low suspicion of malignancy on the basis of gender, age, and nodule size. Cell image analysis was subsequently performed using a Cytometrica BYK Gulden microscope image processor on Feulgen-stained thyroid cytologic smears. A different population of 50 benign and 50 malignant, histologically evaluated nodules was studied in order to establish image analysis criteria suggestive of thyroid malignancy. Ploidy histogram, proliferation index (PI), nuclear area coefficient of variation (NACV), and anisocariosis ratio (AR) were studied. Thyroid cancer was diagnosed in 16 of 58 follicular neoplasms. Only 7 of these lesions were clinically suspicious (43.7%), whereas 14 of 16 (87.5%) malignant tumors were identified by image analysis. Positive and negative predictive values of image analysis versus clinical evaluation were 46.6% versus 30.4% and 92.8% versus 74.3%, respectively. The distribution of ploidy pattern was different in benign versus malignant follicular neoplasms (chi2 8.25, p = 0.016), malignant lesions showing an increased frequency of heteroclonal aneuploid DNA content (37.5% vs. 7.1%). Increased PI (mean +/- standard deviation (SD) = 11.3 +/- 5.7 vs. 7.1 +/- 6.1; p < 0.01) and NACV (mean +/- SD = 25.28 +/- 1.89 vs. 20.14 0.91; p < 0.01) levels were also observed in malignant follicular neoplasms. In conclusion, computer-assisted image analysis may profitably support clinical evaluation in the assessment of thyroid follicular neoplasms.

Two-dimensional electrophoretic analysis of membranous protein from human thyroid tissues and cancer cell lines

Thyroid neoplasm is the most commonly encountered neoplastic disorder in endocrine clinics. Thyroid scan, ultrasonography, and fine needle aspiration cytology (FNAC) are used as diagnostic tools to differentiate a malignant nodule from a benign lesion. There are certain limitations and pitfalls in FNAC, especially in the diagnosing of follicular tumors. The lack of characteristic findings or a specific tumor marker are the most common problems in the preoperative diagnosis of thyroid follicular carcinoma. Although serum thyroglobulin level has been used as a tumor marker for post-operative, well-differentiated thyroid cancer, the assay cannot be used for preoperative diagnosis of thyroid carcinoma. In this study, various thyroid tissues and cancer cell lines including CGTH W-1, CGTH W-3, RO 82 W-1, SW 579 cell lines were used for the investigation of tumor markers. Specific spots were identified in the area near the 60 kDa molecular mass protein and isoelectric point (pI) 5.9 of the CGTH W-1 cell line. These spots could not be found in the papillary or anaplastic thyroid cancer cell lines. Another spot with a molecular weight of about 9.8 kDa with a low pI of 4.8 was present in the CGTH W-1 and RO 82 W-1 cell lines. This spot appeared to be a tumor marker of follicular cancer cells. This spot could not be found in the papillary and anaplastic cancer cell lines and other benign thyroid tissues. Specific proteins that were identified in this study may be useful as tumor markers for follicular thyroid carcinoma.