Thyroid microcarcinoma

Predicting Malignancy of Thyroid Micronodules: Radiomics Analysis Based on Two Types of Ultrasound Elastography Images

RATIONALE AND OBJECTIVES

To develop a multimodal ultrasound radiomics nomogram for accurate classification of thyroid micronodules.

MATERIALS AND METHODS

A retrospective study including 181 thyroid micronodules within 179 patients was conducted. Radiomics features were extracted from strain elastography (SE), shear wave elastography (SWE) and B-mode ultrasound (BMUS) images. Minimum redundancy maximum relevance and least absolute shrinkage and selection operator algorithms were used to select malignancy-related features. BMUS, SE, and SWE radiomics scores (Rad-scores) were then constructed. Multivariable logistic regression was conducted using radiomics signatures along with clinical data, and a nomogram was ultimately established. The calibration, discriminative, and clinical usefulness were considered to evaluate its performance. A clinical prediction model was also built using independent clinical risk factors for comparison.

RESULTS

An aspect ratio ≥ 1, mean elasticity index, BMUS Rad-score, SE Rad-score, and SWE Rad-score were identified as the independent predictors for predicting malignancy of thyroid micronodules by multivariable logistic regression. The radiomics nomogram based on these characteristics showed favorable calibration and discriminative capabilities (AUCs: 0.903 and 0.881 for training and validation cohorts, respectively), all outperforming clinical prediction model (AUCs: 0.791 and 0.626, respectively). The decision curve analysis also confirmed clinical usefulness of the nomogram. The significant improvement of net reclassification index and integrated discriminatory improvement indicated that multimodal ultrasound radiomics signatures might work as new imaging markers for classifying thyroid micronodules.

CONCLUSION

The nomogram combining multimodal ultrasound radiomics features and clinical factors has the potential to be used for accurate diagnosis of thyroid micronodules in the clinic.

Total areola approach for endoscopic thyroidectomy: Six years of experience with the same surgeon

Background

Scarless endoscopic thyroidectomy (ET) is increasingly accepted by the growing amount of surgeons. The target of this study is to assess the efficacy and summarise the experiences of total areola approach for ET (TAAET).

Subjects and Methods

TAAET was performed on 529 patients between January 2016 and October 2021. All operated patients were divided into two groups according to the chronological order. Demographic data, perioperative data and post-operative complications were collected to assess the effectiveness of TAAET.

Results

Five hundred and twenty-eight patients were successfully treated with TAAET, while 1 case was converted to open surgery due to bleeding. The surgical approach consists of lobectomy or total thyroidectomy with or without central lymph node dissection. The post-operative pathology of 433 (81.9%) patients was diagnosed with T1 ~2N0M0. The average number of unilateral lymph node dissection was 7.72 ± 2.44 while the bilateral lymph node was 10.70 ± 3.72. In terms of complications, 38 cases had transient hoarseness, 28 cases had tetany and numbness, 3 cases had post-operative bleeding, 1 case had infection and 33 cases had subcutaneous fluid. There were statistically significant differences between the two groups with respect to transient hoarseness (P < 0.001), tetany and numbness (P = 0.005), intraoperative blood loss (P = 0.003) and operation time for malignant tumour (P < 0.001) because of the accumulation of surgical experience and the maturation of technology.

Conclusions

TAAET which conforms to the anatomical pathway of open thyroidectomy is a safe, effective and feasible technique and is highly suitable for novices.

Risk stratification of papillary thyroid microcarcinomas via an easy-to-use system based on tumor size and location: clinical and pathological correlations

Introduction: We aimed to determine whether two clinically accessible parameters, tumor size and location within the thyroid, correlate with clinicopathological features that are predictors of high risk in papillary thyroid microcarcinomas (PTMCs). Materials and Methods: PTMC cases were obtained from the database of the Department of Pathology, Emergency County Hospital, Târgu Mureş, Romania. Four tumor groups were created based on tumor size and location: Group I (≥5 mm, subcapsular), Group II (≥5 mm, nonsubcapsular), Group III (<5 mm, subcapsular), and Group IV (<5 mm, nonsubcapsular) PTMCs. Clinicopathological features and follow-up data were compared by univariate and multivariate analysis. Results: Our study included 164 PTMCs (n=70/20/19/55 in Groups I/II/III/IV, respectively). High-grade morphological features, such as plump pink cells (p=0.010), tumor desmoplasia (p=0.022) and sclerosis (p=0.001), infiltrative tumor borders (p=0.005), positive resection margins (p=0.005), invasion into the perithyroid adipose tissue (p=0.001), irregular nuclear membranes (p=0.004), and pseudoinclusions (p=0.001) were significantly more prevalent among Group I PTMCs. Group IV PTMCs were characterized by a paucity of the above-mentioned morphological features, while Group II and III PTMCs displayed intermediate morphological profiles. Conclusions: Group I PTMCs proved to be associated with more aggressive morphological features and might need a more careful clinical approach.

Continuing controversy regarding individualized surgical decision-making for patients with 1-4 cm low-risk differentiated thyroid carcinoma: A systematic review

Implementing high-quality randomized controlled trials is difficult for patients with 1-4 cm low-risk differentiated thyroid carcinoma (DTC). Controversy exists regarding whether lobectomy (LT) or total thyroidectomy (TT) is the optimal surgical approach over the short term and long term. Inconsistent recommendations have led to confusion amongst surgeons. Consequently, the outcomes of patients may be influenced. A great deal of new literature is published monthly, and there have been numerous studies supporting both LT and TT. Surgeons must spend considerable time and energy clarifying why controversy exists and which studies should be used as references. We selected 19 recent guidelines/consensuses for surgical approach in treating of 1-4 cm DTC. This study presents various topics relevant to the present debate, including disease-specific survival (DSS), persistence/recurrence, and complications between LT and TT, in patients with 1-4 cm low-risk DTC. This review includes a discussion of the background of those recommendations with regard to various medical, cultural and geographic environments. Additionally, recent technologies and future directions for current issues in risk identification were integrated into the review to provide a reference for individualized decision-making for patients with 1-4 cm low-risk DTC. Given different national conditions, there are different points of emphasis amongst the guidelines. Consideration of surgical approach should consider the character of both surgeons and patients. We should balance the relative benefits, risks and resulting quality of life in order to perform individualized surgical decision-making, and to make reasonable decisions in employing either TT or LT.

Factors contributing to the resistance of the thyrocyte to hydrogen peroxide

We studied the mechanism that may explain the relative resistance of thyrocytes to H₂O₂ compared to other cell types. Ability to degrade H₂O₂, glutathione peroxidase (GPx) activity, heme oxygenase-1 (HO-1) expression, cell survival and capacity to repair DNA damage after H₂O₂ exposure or irradiation were measured in human thyrocytes in primary culture and compared to the values obtained in human T-cells and different cell lines. Compared to other cell types, thyrocytes presented a low mortality rate after H₂O₂ exposure, rapidly degraded extracellular H₂O₂ and presented a high basal seleno-dependent GPx activity. Only in thyrocytes, H₂O₂ up-regulated GPx activity and expression of HO-1 mRNA. These effects were not reproduced by irradiation. DNA damage caused by H₂O₂ was more slowly repaired than that caused by irradiation and not repaired at all in T-cells. Our study demonstrates that the thyrocyte has specific protective mechanisms against H₂O₂ and its mutagenic effects.

Association of BRAF gene and TSHR with cervical lymph node metastasis of papillary thyroid microcarcinoma

Differences in BRAF gene mutation frequency and thyroid-stimulating hormone receptor (TSHR) protein expression in thyroid tissues were detected to investigate their association with local tissue invasion and cervical lymph node metastasis potential of papillary thyroid microcarcinoma (PTMC). The BRAF gene mutation frequency and TSHR expression in PTMC patients were detected via qPCR and immunohistochemical method, and the association between them was discussed combined with the clinical and pathological parameters. Kruskal-Wallis test was used for the univariate correlation analyses and comparison of mutation rate and expression rate, and Chi-square test was used for the association of central lymph node metastasis with BRAF gene and TSHR. The BRAF^V600E mutation only existed in patients with thyroid cancer. Τhe larger the number of metastatic central lymph nodes was, the higher the proportion of BRAF^V600E mutation would be. Τhe BRAF^V600E mutation was related to the primary lesion size, capsular infiltration and lymph node metastasis of PTMC (P<0.05). The expression of TSHR in PTMC tissues was < those in thyroid benign lesions and para-carcinoma normal tissues, which was positively associated with the central lymph node metastasis (P<0.05). Τhe low expression of TSHR was related to the primary lesion size, capsular infiltration and metastatic lymph nodes of PTMC (P<0.05). The BRAF^V600E and TSHR may be involved in the occurrence and lymphatic metastasis of PTMC. The BRAF^V600E mutation has no association with the TSHR protein expression (P=0.256), but the coincidence coefficient indicates that their diagnostic significance in PTMC is not similar, so BRAF^V600E mutation and TSHR protein expression can be used jointly in the prediction of invasion and lymph node metastasis of PTMC, which may be more meaningful for clinical guidance.

Inhibitory roles of miR‑9 on papillary thyroid cancer through targeting BRAF

MicroRNA‑9 (miR‑9) is reported to be underexpressed in papillary thyroid carcinoma (PTC) tissues; however, the molecular mechanisms underlying the implication of miR‑9 in PTC have yet to be elucidated. The present study aimed to explore the potential roles of miR‑9 in PTC. PTC tissue samples and paired non‑cancerous adjacent tissues were collected from 60 patients with PTC. The human TPC‑1 thyroid gland papillary carcinoma cell line was used to investigate the molecular mechanisms underlying the roles of miR‑9 in PTC. The levels of miR‑9 and its downstream target gene BRAF were detected through reverse transcription‑quantitative polymerase chain reaction. MTT assay and flow cytometry were performed to evaluate cell viability and apoptosis, respectively. A mouse xenograft tumor model was established to observe the effects of miR‑9 on thyroid gland tumorigenesis in vivo. The present study revealed that the expression of miR‑9 was significantly reduced in PTC tissues compared with paired normal tissues. In addition, miR‑9 upregulation suppressed the expression of BRAF in TPC‑1 cells in vitro. Luciferase reporter assay demonstrated that BRAF may be a direct target gene of miR‑9 in TPC‑1 cells. In addition, following transfection with miR‑9 mimics, the viability of TPC‑1 cells was suppressed and their apoptosis was enhanced; conversely, transfection with miR‑9 inhibitor exerted the opposite effects in vitro. miR‑9 overexpression or downregulation also affected in vivo PTC tumorigenesis in athymic mice. The present findings suggested that miR‑9 may suppress the viability of PTC cells and inhibit tumor growth through directly targeting the expression of BRAF in PTC.

Interstitial fibrosis in papillary thyroid microcarcinoma and its association with biological behavior

Previous studies have revealed that fibrosis may affect the biological behavior of tumors, however associated research on papillary thyroid microcarcinoma (PTMC) is rare. The aim of the present study was to explore the association between interstitial fibrosis (IF) and the biological behavior of PTMC. In the present study, a total of 511 consecutive cases of PTMC were evaluated for the presence of IF and its association with clinical parameters and pathologic biomarkers. IF was identified in 340 of the 511 consecutive cases and it was significantly associated with the age (P=0.033), tumor diameter (P=0.017) and lymphocytic metastasis (P<0.001) of the patient. There were significantly more female in the fibrosis group than in fibrosis-absent group (P=0.024). In the analysis of clinical biomarkers using immunohistochemistical staining, IF was significantly associated with cytokeratin 19 (P=0.008) and galectin-3 (P=0.022). Analysis of patient outcomes indicated that IF was an independent prognostic factor of recurrence (hazard ratio = 2.181; 95% confidence interval = 1.163-4.090; P=0.015). These findings suggest that the combined effect of a patient's age, sex and tumor size may potentially contribute to fibrotic lesions and IF was a factor contributing to poor prognosis in patients with PTMC.

Papillary thyroid microcarcinoma: the significance of high risk features

Background

Papillary carcinomas that measure 1.0cm or less are diagnosed as papillary thyroid microcarcinomas (PTMs). The clinical significance and recommendations for management of these PTMs is still evolving. The objective of the study was to compare the characteristics of small (<5mm) to large (≥ 5mm) papillary thyroid microcarcinomas.

Methods

Amongst 1459 sequential patients undergoing thyroid surgery at a single center, 132 (9%) cases were diagnosed with PTM. We performed a retrospective analysis of these cases using Fisher’s Exact Test. The statistical significance was set at p < 0.05 a priori.

Results

A relationship between large PTM and high risk features was observed only for extra-thyroidal cancer extension (ETE). Six of 57 large PTM (11%) but none of the 75 small PTM had ETE (p < 0.01). Lymph node metastases were associated with both small PTM (5/9 cases) and large PTM (4/9 cases). A distant metastases was diagnosed in association with a small PTM.

Conclusions

For PTM, neither small cancer size, nor the absence of high-risk features, excluded the possibility of synchronous lymph node metastases.

Association of FOXE1 polyalanine repeat region with thyroid cancer is dependent on tumour size

OBJECTIVE

Polymorphisms in the thyroid transcription factor forkhead factor E1 (FOXE1) gene have been implicated in the genetic susceptibility to differentiated thyroid cancer, but little is known about their effect on tumour characteristics. The objective of this study was to determine the contribution of the FOXE1 polyalanine repeat region to the susceptibility to thyroid cancer and to its clinical characteristics.

DESIGN, PATIENTS AND MEASUREMENTS

A total of 500 patients with sporadic thyroid cancer (440 papillary and 60 follicular thyroid carcinoma) and 502 healthy controls were included in this case-control association study. The number of FOXE1 alanine repeats in each subject was determined by PCR and multiplex fragment analysis by capillary electrophoresis. FOXE1 genotype and allele frequencies among groups were compared by logistic regression and adjusted for sex and age at diagnosis. Data were analysed according to cancer subtype, tumour size and the presence of lymph node or distant metastasis.

RESULTS

FOXE1 alleles with 16 or more alanine repeats were more frequent in patients with tumour size > 1 cm compared to tumour size ≤ 1 cm (adjusted OR 1·44; 95% CI 1·05-1·88; P = 0·019). Genotypes containing at least one allele with 16 or more alanine repeats were associated with larger tumour size (adjusted OR 1·71; 95% CI 1·15-2·57; P = 0·009). No significant differences were observed between cancer subtypes or the presence/absence of metastasis.

CONCLUSIONS

FOXE1 polyalanine repeat polymorphisms are associated with thyroid cancer, but only for tumours larger than 1 cm, suggesting a role in disease progression.

Total thyroidectomy versus lobectomy in conventional papillary thyroid microcarcinoma: Analysis of 8,676 patients at a single institution

BACKGROUND

Because there is a controversy regarding the management of papillary thyroid microcarcinoma, the purpose of this study was to compare lobectomy with total thyroidectomy as a primary operative treatment for papillary thyroid microcarcinoma. Loco-regional recurrence in the contralateral remnant lobe can be managed safely by completion thyroidectomy via the previous scar. However, reoperation for operation bed (thyroidectomy site) or regional lymph node (central or lateral) recurrence generally is associated with morbidity. Therefore, we analyzed overall loco-regional recurrence and loco-regional recurrence outside of the contralateral remnant lobe separately.

METHODS

We retrospectively reviewed 8,676 conventional patients with papillary thyroid microcarcinoma who underwent thyroidectomy.

RESULTS

Lobectomy was performed in 3,289 (37.9%) patients, and total thyroidectomy was performed in 5,387 (62.1%) patients. Total thyroidectomy significantly decreased the risk of overall loco-regional recurrence (adjusted hazard ratio 0.398, P < .001). However, total thyroidectomy did not significantly decrease the risk of loco-regional recurrence outside of the contralateral remnant lobe (adjusted hazard ratio 0.880, P = .640). Particularly in conventional papillary thyroid microcarcinoma patients with multifocality, total thyroidectomy significantly decreased the risk of overall loco-regional recurrence (adjusted hazard ratio 0.284, P = .002) and loco-regional recurrence outside of the contralateral remnant lobe (adjusted hazard ratio 0.342, P = .020).

CONCLUSION

Although lobectomy is associated with contralateral remnant lobe recurrence, lobectomy did not increase the risk of loco-regional recurrence outside of the contralateral remnant lobe in patients with papillary thyroid microcarcinoma, except in those with multifocality. Because recurrence in the contralateral remnant lobe can be managed safely by completion thyroidectomy, lobectomy may be a safe operative option for select patients with papillary thyroid microcarcinoma without multifocality.

Diagnostic Value of Conventional Ultrasonography Combined with Contrast-Enhanced Ultrasonography in Thyroid Imaging Reporting and Data System (TI-RADS) 3 and 4 Thyroid Micronodules

BACKGROUND The present study was conducted to investigate the diagnostic performance of conventional ultrasonography (US) combined with contrast-enhanced ultrasonography (CEUS) in thyroid micronodules with thyroid imaging reporting and data system (TI-RADS) category 3 and 4. MATERIAL AND METHODS The features of conventional US and CEUS ion 102 case of thyroid micronodule samples, which were diagnosed based on pathological and clinical examination, were retrospectively analyzed. Logistic regression analysis was used to analyze the diagnostic accuracy in malignant thyroid micronodules. Receiver operator characteristic (ROC) curve was used to assess the performance of those 2 technologies. RESULTS A significant difference in age was found between the benign and malignant groups. The benign and malignant groups showed significant differences in shape, margin, aspect ratio (A/T) ≥1, microcalcification, suspicious lymph gland, enhancement time, enhancement pattern, enhancement intensity, nodule sizes, enhancement margins, and rim-like enhancement. Logistic regression analysis of conventional US showed that A/T ≥1, irregular shape, microcalcification, and suspicious lymph glands are risk factors for thyroid micronodules, while logistic regression analysis of CEUS showed that slow enhancement time and absence of rim-like enhancement are risk factors for thyroid micronodules. Logistic regression analysis of conventional US combined with CEUS demonstrated that A/T ≥1, microcalcification, suspicious lymph gland, slow enhancement time, and absence with rim-like enhancement are risk factors. The ROC curve for conventional US, CEUS, and conventional US combined with CEUS were 90.0%, 90.7%, 99.0%, respectively. CONCLUSIONS Our results show that conventional US combined with CEUS had superior diagnostic performance for TI-RADS 3 and 4 thyroid micronodules compared with conventional US and CEUS alone.

'Incidental' and 'non-incidental' thyroid papillary microcarcinomas are two different entities

OBJECTIVE

Papillary thyroid microcarcinomas (microPTC) may be 'incidental' (Inc-microPTC), occasionally found at histology after surgery for benign disease or 'non-incidental' (Non-Inc-microPTC), diagnosed on clinical grounds. It is unclear whether these different microPTC reflect the same disease. The aim of the study was to compare Inc-microPTC and Non-Inc-microPTC for clinical and histological features as well as for serum TSH, a known factor involved in PTC development.

DESIGN

We evaluated histology and serum TSH levels of consecutive patients submitted to thyroidectomy for goiter with compressive symptoms or for cytological diagnosis suspicious/indicative of PTC.

METHODS

In total, 665 consecutive patients (259 with a single thyroid nodule, SN and 406 with a multinodular gland, MN) were included in the study. According to histology, patients were classified as: benign nodular goiter (Benign, n=291); Inc-microPTC (n=92); Non-Inc-microPTC (n=67) and PTC≥1cm (macroPTC, n=215).

RESULTS

Inc-microPTC were significantly more frequent in MN than in SN (66/406, 16.2% vs 26/259, 10.0%, P=0.02). Patients with Inc-microPTC compared with Non-Inc-microPTC were older (mean age±s.d. 53.3±13.2 years vs 44.9±14.8 years, P=0.0002), had a smaller tumor size (median 4mm vs 9mm, P<0.0001), a higher frequency of multifocality (70/92, 76.1% vs 35/67, 52.2% P=0.001) and lower levels of TSH (median 0.6mIU/L, IR: 0.4-1.0mIU/L vs value 1. mIU/L, IR: 0.6-1.4mIU/L vs P=0.0001).

CONCLUSION

Incidental and non-incidental papillary thyroid microcarcinomas appear to be two different entities.

Short-term Follow-up US Leads to Higher False-positive Results Without Detection of Structural Recurrences in PTMC

To investigate the value of the annual follow-up neck ultrasonography (US) for postoperative surveillance in patients with papillary thyroid microcarcinoma (PTMC). This retrospective study has been approved by our institutional review board (IRB) with waiver for informed consent. A total of 375 patients diagnosed as PTMCs, who underwent total thyroidectomy with radioiodine remnant ablation were included, to identify the recurrence rate and the false-positive rate of annual ultrasound. The number, interval, and the results of follow-up US or fine needle aspiration were obtained from electronic medical records. Four (1.1%, 4/375) recurrences were found 3 years after the initial treatment, and only 1 patient (0.3%, 1/375) had a metastatic lymph node larger than 8 mm in the shortest diameter on US found 7.6 years after initial treatment with biochemical abnormalities. Cumulative risk of having at least 1 false-positive exam was 8.3% by the 8th US, and 8.1% by the 8-9 year follow-up. Cox multivariate regression showed shorter interval of follow-up US and presence of lymph node metastasis at initial surgery are independent predictors affecting the cumulative false-positive results (hazard ratio [HR], 0.60; 95% confidence interval [CI]: 0.49-0.73; P < 0.001 and HR, 2.19; 95% CI: 1.01-4.75; P = 0.048, respectively). Short-term follow-up US can result in higher cumulative false-positive results without detection of meaningful recurrences in patients with PTMCs who do not have biochemical abnormalities.

Real-Time PCR Cycle Threshold Values for the BRAFV600E Mutation in Papillary Thyroid Microcarcinoma May Be Associated With Central Lymph Node Metastasis: A Retrospective Study

Papillary thyroid microcarcinoma (PTMC) usually has excellent prognosis, but a small subset shows aggressive behavior. Although the B-Raf proto-oncogene, serine/threonine kinase (BRAF)V600E mutation is the most common oncogenic alteration in PTMCs, it is frequently heterogeneously distributed within tumors. The aim of this study was to investigate the association of the BRAFV600E mutation found in fine needle aspirates from PTMCs with known clinicopathologic prognostic factors, based on both its presence and a quantitative approach that uses cycle threshold (Ct) values obtained by a real-time PCR technique. The 460 PTMC patients were included, with 367 patients having the BRAFV600E mutation. Clinicopathologic variables were compared between patients with and without the BRAFV600E mutation. BRAFV600E Ct values were compared according to clinicopathologic prognostic factors. Multivariate analyses were performed to evaluate factors predicting extrathyroidal extension and central and lateral lymph node metastasis (LNM). Each analysis used either the BRAFV600E mutation status or the Ct value as an independent variable for all the study patients and the 367 BRAFV600E-positive patients. Receiver-operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of BRAFV600E Ct values in predicting central and lateral LNM. The BRAFV600E mutation status was not associated with clinicopathologic prognostic factors among the 460 PTMC patients. Of the 367 BRAFV600E-positive patients, Ct values were significantly lower in patients with central and lateral LNM (P < 0.001, P = 0.007). The Ct value was the only independent factor to predict central LNM (OR 0.918, P = 0.025). The area under the ROC curve (AUC) for diagnosing central LNM was 0.623 (sensitivity, 50.0%; specificity, 71.9%) and for diagnosing lateral LNM, it was 0.796 (sensitivity, 71.4%; specificity, 94.7%). In conclusion, real-time PCR Ct values for the BRAFV600E mutation obtained from fine needle aspirates can be associated with central LNM in PTMC patients. Although BRAFV600E Ct values did not reach statistical significance for predicting lateral LNM in our study, further validation through larger studies can be used to overcome any possible type-II errors. With further studies, Ct values for the BRAFV600E mutation obtained from fine needle aspirates may have important implications for predicting both central and lateral LNM in patients with PTMCs.

Association of RET genetic polymorphisms and haplotypes with papillary thyroid carcinoma in the Portuguese population: a case-control study

Thyroid cancer has a multifactorial aetiology resulting from the interaction of genetic and environmental factors. Several low penetrance susceptibility genes have been identified but their effects often vary between different populations. Somatic point mutations and translocations of the REarranged during Transfection (RET) proto-oncogene are frequently found in thyroid cancer. The aim of this case-control study was to determine the effect of four well known RET single nucleotide polymorphisms (SNPs) on the risk for differentiated thyroid carcinoma. A total of 545 Portuguese patients and 543 controls were genotyped by PCR and restriction enzyme analysis, for the following SNPs: G691S (exon 11, rs1799939 G/A), L769L (exon 13, rs1800861 T/G), S836S (exon 14, rs1800862 C/T), and S904S (exon 15, rs1800863 C/G). The minor allele of S836S was overrepresented in patients with papillary thyroid carcinoma (PTC) when compared to controls (OR 1.57; 95% CI 1.05–2.35; p = 0.026). The GGTC haplotype was also overrepresented in PTC (OR 2.51; 95% CI 1.07–5.91; p = 0.029). No associations were found in follicular thyroid carcinoma (FTC). Multivariate logistic regression analysis showed no differences regarding gender, age at diagnosis, lymph node or distant metastasis. However, a near significant overrepresentation of the minor alleles of G691S and S904S was found in patients with tumours greater than 10 mm of diameter at diagnosis. These data suggest that the RET S836S polymorphism in exon 14 and the GGTC haplotype are risk factors for PTC, but not FTC, and that the G691S/S904S polymorphisms might be associated with tumour behaviour.

Acoustic radiation force impulse imaging: a new tool for the diagnosis of papillary thyroid microcarcinoma

PURPOSE

To evaluate the diagnostic performance of ARFI imaging in differentiating between benign and malignant thyroid nodules <1 cm.

MATERIALS AND METHODS

173 pathologically proven thyroid nodules (77 benign, 96 malignant) in 157 patients were included in this study. Receiver-operating characteristic curve (ROC) analyses were performed to assess the diagnostic performance of conventional ultrasound (US) and ARFI imaging in papillary thyroid microcarcinoma (PTMC). The independent risk factors for predicting PTMC were evaluated.

RESULTS

The mean SWV value of benign and malignant thyroid nodules were 2.57 ± 0.79 m/s (range: 0.90-4.92 m/s) and 3.88 ± 2.24 m/s (range: 1.49-9.00 m/s) (P = 0.000). Az for VTI elastography score was higher than that for hypoechoic, absence of halo sign, and type III vascularity (P < 0.05). The optimal cut-offs for VTI elastography score and SWV were score 4 and 3.10 m/s. Gender, hypoechoic, taller than wide, VTI elastography score ≥ 4, and SWV > 3.10 m/s had been found to be independent risk factors for predicting PTMC.

CONCLUSION

ARFI elastography can provide elasticity information of PTMC quantitatively (VTQ) and directly reflects the overall elastic properties (VTI). Gender, hypoechogenicity, taller than wide, VTI elastography score ≥ 4, and SWV > 3.10 m/s are independent risk factors for predicting PTMC. ARFI elastography seems to be a new tool for the diagnosis of PTMC.

Clinical value of visually identifiable 18F-fluorodeoxyglucose uptake in primary papillary thyroid microcarcinoma

OBJECTIVE

This study evaluates the relationship between visually identifiable (18)F-fluorodeoxyglucose (FDG) uptake in primary papillary thyroid microcarcinoma (PTMC) and tumor aggressiveness.

STUDY DESIGN

Historical cohort study.

SETTING

Tertiary care center.

METHODS

Clinicopathological factors and PET/CT findings of 219 PTMC surgical patients who underwent preoperative (18)F-FDG positron emission tomography/computed tomography (PET/CT) were retrospectively reviewed.

RESULTS

(18)F-FDG uptake was observed in the tumors of 124 (56.6%) patients. Tumor size (odds ratio [OR] = 1.774; 95% confidence interval [CI], 1.416-2.223; P < .0001) and Hashimoto thyroiditis (OR = 2.815; CI, 1.237-6.404; P = .014) independently predicted (18)F-FDG uptake. Tumor size (OR = 1.495; CI, 1.217-1.835; P < .0001) and BRAF(V600E) mutation (OR = 3.320; CI, 1.056-10.432; P = .040) independently predicted extrathyroidal invasion. Multiplicity (OR = 2.375; CI, 1.278-4.415; P = .006) independently predicted central lymph node metastasis.

CONCLUSION

(18)F-FDG uptake in PTMC depends on tumor size and Hashimoto thyroiditis. Therefore, preoperative PET/CT for PTMC may not help in evaluating tumor aggressiveness.

Clinical outcome in differentiated thyroid carcinoma and microcarcinoma

INTRODUCTION

Due to the frequent use of neck ultrasonography, the incidence of differentiated thyroid microcarcinoma (DTMC), defined as a lesion with greatest dimension ≤1 cm, is increasing worldwide. Although DTMC generally has a lower aggressivity and a better prognosis than differentiated thyroid carcinoma (DTC), some cases of clinically aggressive DTMC were found. The aim of this study is to compare the rate of recurrence in DTMC and DTC, during a 3-year follow-up.

METHODS

Patients with differentiated thyroid carcinoma, who underwent total thyroidectomy and postoperative (131)I-RAI ablation, were stratified according to lesion diameter (DTC for diameter > 1 cm or DTMC ≤ 1 cm). After surgery, patients underwent a 3-year follow-up. Recurrent disease was defined on the basis of positive biochemical (Tg > 2 ng/ml under TSH-suppression or after rhTSH-stimulation) and/or imaging (US, WBS, CT, PET/CT) findings.

RESULTS

449 patients have been included in the final analysis. Linfoadenectomy rate and RAI ablative dose were significantly higher in DTC than in DTMC (32.7% vs. 22.4%, p = 0.018 and 112.3 ± 21 vs. 68.3 ± 24.1 mCi, p < 0.001). During the follow-up, 50 carcinoma recurrences occurred, more frequent in DTC than in DTMC (15.6% vs. 7.6%, p = 0.010). After adjustment for gender, age, rate of lymph node dissection and 131I dose of RAI treatment, the difference in the risk of recurrence was no longer significant among DTC and DTMC patients (HR: 1.585, 95% CI 0874-2877, p = 0.130).

CONCLUSIONS

The prediction of disease severity cannot be based exclusively on lesion diameter. A more careful therapeutic approach and follow-up should be recommended in DTMC patients.

[Current treatment strategies for papillary thyroid microcarcinoma]

The increase in the incidence of thyroid cancer is accompanied by a mortality rate that is stable or perhaps even slightly decreasing. This phenomenon is due to the increased frequency of papillary microcarcinomas (thyroid tumors with a diameter of less than 1 cm), which is presumably attributable to the improved diagnosis enabled by high resolution ultrasound and fine needle aspiration cytology. The American and European Thyroid Associations have recently published new guidelines for the diagnosis and therapy of differentiated thyroid tumors. These guidelines are aimed at minimizing the diagnostic and therapeutic procedures without reducing their effectiveness. This goal is particularly important for papillary thyroid microcarcinoma patients, who have an excellent prognosis and almost normal life expectancy. This article summarizes the history of thyroid surgery and introduces papillary thyroid microcarcinoma--an important topic in modern thyroid oncology. Current methods for diagnosis, treatment and follow-up care of this disease are discussed.

A solitary hyperfunctioning thyroid nodule harboring thyroid carcinoma: review of the literature

Hyperfunctioning nodules of the thyroid are thought to only rarely harbor thyroid cancer, and thus are infrequently biopsied. Here, we present the case of a patient with a hyperfunctioning thyroid nodule harboring thyroid carcinoma and, using MEDLINE literature searches, set out to determine the prevalence of and characteristics of malignant “hot” nodules as a group. Historical, biochemical and radiologic characteristics of the case subjects and their nodules were compared to those in cases of benign hyperfunctioning nodules. A literature review of surgical patients with solitary hyperfunctioning thyroid nodules managed by thyroid resection revealed an estimated 3.1% prevalence of malignancy. A separate literature search uncovered 76 cases of reported malignant hot thyroid nodules, besides the present case. Of these, 78% were female and mean age at time of diagnosis was 47 years. Mean nodule size was 4.13 ± 1.68 cm. Laboratory assessment revealed T₃ elevation in 76.5%, T₄ elevation in 51.9%, and subclinical hyperthyroidism in 13% of patients. Histological diagnosis was papillary thyroid carcinoma (PTC) in 57.1%, follicular thyroid carcinoma (FTC) in 36.4%, and Hurthle cell carcinoma in 7.8% of patients. Thus, hot thyroid nodules harbor a low but non-trivial rate of malignancy. Compared to individuals with benign hyperfunctioning thyroid nodules, those with malignant hyperfunctioning nodules are younger and more predominantly female. Also, FTC and Hurthle cell carcinoma are found more frequently in hot nodules than in general. We were unable to find any specific characteristics that could be used to distinguish between malignant and benign hot nodules.