Role of the Degree of Vascular Invasion in Predicting Prognosis of Follicular Thyroid Carcinoma

OBJECTIVE

The present study investigated the prognostic factors for follicular thyroid carcinoma (FTC) with the incorporation of the histologic subtype and degree of vascular invasion (VI).

PATIENTS

The records of 474 patients with FTC confirmed by surgical specimens at Ito Hospital from January 2005 to December 2014 were reviewed in this retrospective cohort study. The Cox proportional hazard model was used to determine factors associated with disease-free survival (DFS) and distant metastasis-free survival.

RESULTS

Of the 474 patients, 140 (30%) had minimally invasive FTC, 260 (55%) had encapsulated angio-invasive FTC, and 74 (16%) had widely invasive FTC. Among the 428 patients with M0 FTC, the 10-year DFS rates of patients with minimally invasive FTC (n = 133), encapsulated angio-invasive FTC (n = 247), and widely invasive FTC (n = 48) were 97.3%, 84.2%, and 69.9% (P < .001), respectively. A multivariate analysis identified aged ≥55 years (hazard ratio [HR], 2.204; 95% CI, 1.223-3.969; P = .009), histologic subtype (HR, 2.068; 95% CI, 1.064-4.021; P = .032), VI of ≥2 (HR, 6.814; 95% CI, 3.157-14.710; P < .001), and tumor size >40 mm (HR, 2.014; 95% CI, 1.089-3.727; P = .026) as independent negative prognostic factors for DFS.

CONCLUSION

Our study results may enable us to stratify the prognosis of FTC more accurately by combining the histologic subtype with the degree of VI ≥2, aged ≥55 years, and tumor size >40 mm.

On-the-fly Raman microscopy guaranteeing the accuracy of discrimination

Accelerating the measurement for discrimination of samples, such as classification of cell phenotype, is crucial when faced with significant time and cost constraints. Spontaneous Raman microscopy offers label-free, rich chemical information but suffers from long acquisition time due to extremely small scattering cross-sections. One possible approach to accelerate the measurement is by measuring necessary parts with a suitable number of illumination points. However, how to design these points during measurement remains a challenge. To address this, we developed an imaging technique based on a reinforcement learning in machine learning (ML). This ML approach adaptively feeds back "optimal" illumination pattern during the measurement to detect the existence of specific characteristics of interest, allowing faster measurements while guaranteeing discrimination accuracy. Using a set of Raman images of human follicular thyroid and follicular thyroid carcinoma cells, we showed that our technique requires 3,333 to 31,683 times smaller number of illuminations for discriminating the phenotypes than raster scanning. To quantitatively evaluate the number of illuminations depending on the requisite discrimination accuracy, we prepared a set of polymer bead mixture samples to model anomalous and normal tissues. We then applied a home-built programmable-illumination microscope equipped with our algorithm, and confirmed that the system can discriminate the sample conditions with 104 to 4,350 times smaller number of illuminations compared to standard point illumination Raman microscopy. The proposed algorithm can be applied to other types of microscopy that can control measurement condition on the fly, offering an approach for the acceleration of accurate measurements in various applications including medical diagnosis.

An Unlikely Source of Iodine Uptake: A Bronchogenic Cyst Masquerading as Metastatic Thyroid Cancer

Radioactive iodine therapy and posttreatment scanning are essential components of differentiated thyroid carcinoma treatment and detection of metastatic disease. False-positive results can be seen on an I-131 scan and are important for clinicians to be aware of. Here, we present a case of a 33-year-old female with follicular thyroid carcinoma who was noted to have an area of moderate uptake in the chest on a whole-body scan following remnant ablation with 30 mCi of I-131 (1.11GBq) concerning for a metastatic hilar lymph node. This was determined to be a mediastinal bronchogenic cyst on surgical pathology. It has been previously proposed that the expression of sodium iodide symporters in some bronchogenic cysts could be the mechanism by which iodine uptake is seen within them. We were able to demonstrate positive immunohistochemical staining for both sodium iodide symporter and the associated paired box gene 8 transcription factor in the cyst sample, which supports the proposed theory.

Prevalence and diagnostic significance of non-invasive follicular thyroid neoplasm with papillary-like nuclear features in Japan-A multi-institutional study

This multi-institutional study investigated non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) frequency and its diagnostic significance in Japan. We reviewed 4008 thyroid nodules resected in six institutions before NIFTP was proposed. Overall, 26 cases diagnosed as non-invasive encapsulated follicular variant of papillary thyroid carcinoma (PTC) and 145 cases of follicular thyroid adenoma (FTA) were included. Of these nodules, 80.8% and 31.0%, respectively, were NIFTPs. In five institutions, NIFTPs were more commonly found in FTA than in PTC nodules. When NIFTP was included with PTC, the overall prevalence was 2.3%, with rates in five institutions below 5.0% (0.8%-4.4%). One NIFTP case with nuclear score 3 revealed nodal metastasis 2.5 years post-resection, and the carcinoma cells were immunohistochemically positive for BRAF. FTAs or NIFTPs with nuclear score 2 did not metastasize. NIFTP was more common among FTA than among PTC nodules, possibly due to underdiagnosis of PTC on nuclear findings. Considering the clinical findings, molecular pathogenesis, and therapeutic strategy in Japan, NIFTP with nuclear score 2 is not different from FTA, and use of this entity terminology is not meaningful. In contrast, NIFTP with nuclear score 3 has potential for metastasis and BRAFV600E mutation. Therefore, in NIFTP cases, nuclear scores 2 and 3 should be separately reported.

Deep Learning-Based Differential Diagnosis of Follicular Thyroid Tumors Using Histopathological Images

Deep learning systems (DLSs) have been developed for the histopathological assessment of various types of tumors, but none are suitable for differential diagnosis between follicular thyroid carcinoma (FTC) and follicular adenoma (FA). Furthermore, whether DLSs can identify the malignant characteristics of thyroid tumors based only on random views of tumor tissue histology has not been evaluated. In this study, we developed DLSs able to differentiate between FTC and FA based on 3 types of convolutional neural network architecture: EfficientNet, VGG16, and ResNet50. The performance of all 3 DLSs was excellent (area under the receiver operating characteristic curve = 0.91 ± 0.04; F1 score = 0.82 ± 0.06). Visual explanations using gradient-weighted class activation mapping suggested that the diagnosis of both FTC and FA was largely dependent on nuclear features. The DLSs were then trained with FTC images and linked information (presence or absence of recurrence within 10 years, vascular invasion, and wide capsular invasion). The ability of the DLSs to diagnose these characteristics was then determined. The results showed that, based on the random views of histology, the DLSs could predict the risk of FTC recurrence, vascular invasion, and wide capsular invasion with a certain level of accuracy (area under the receiver operating characteristic curve = 0.67 ± 0.13, 0.62 ± 0.11, and 0.65 ± 0.09, respectively). Further improvement of our DLSs could lead to the establishment of automated differential diagnosis systems requiring only biopsy specimens.

Global incidence and prevalence of differentiated thyroid cancer in childhood: systematic review and meta-analysis

Objective

Differentiated thyroid cancer (DTC) is rare in childhood and adolescence although it represents the most frequent endocrine malignancy in this population. DTC includes both papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC). Most pediatric DTCs are PTCs, while FTCs are rare. To date, no systematic reviews on the global epidemiology of pediatric and adolescent DTC have been published. This systematic review and meta-analysis aims to estimate the overall incidence and prevalence of DTCs in patients aged 0-19 years.

Methods

The systematic research was conducted from January 2000 to December 2021 through MEDLINE via PubMed, Cochrane Library, and Embase databases. Two separate meta-analyses were performed for PTC and FTC.

Results

After the selection phase, a total of 15 studies (3,332 screened) met the inclusion criteria and are reported in the present systematic review. Five studies were conducted in Europe, five in North America, two in South America, one in Asia, one reported data for 49 countries and territories across the five continents, and one from both the USA and Africa. Most of the studies (n = 14) reported data obtained from national registries, and only one provided information collected from hospital medical records. Beyond the actual trend over time, our study reported a pooled global incidence rate (IR) of PTC and FTC in the pediatric age of 0.46 (95% CI: 0.33-0.59) and 0.07 (95% CI: 0.02-0.12) per 100,000 person-years, respectively. The highest IRs were recorded among Caucasian girls, and the lowest in black or other races/ethnicities.

Conclusion

Our data confirm that DTC in the pediatric population is a rare condition. The pooled IRs of the studies included in this meta-analysis are ~0.5 for PTC, which is the most common histological type when both genders and all age groups are considered. The implementation of a prospective international registry on pediatric DTC, as part of the wider European Registries for Rare Endocrine Conditions, has been recently proposed. In addition to providing relevant information on the clinical behavior of this rare disease, standardization of data collection will be pivotal to fill current gaps and allow an accurate estimation of the real incidence and risk factors of DTC.

Evaluation and management of pediatric thyroid nodules and thyroid cancer at a single institution after adoption of the American Thyroid Association 2015 guidelines

OBJECTIVES

The study purpose is to correlate clinical findings with rates of differentiated thyroid cancer (DTC) in a cohort of children presenting with thyroid nodules at a single institution since the adoption of the 2015 American Thyroid Association (ATA) Guidelines Task Force on Pediatric Thyroid Cancer.

METHODS

Clinical, radiographic, and cytopathologic findings were retrospectively analyzed in a pediatric cohort (≤19 years) identified with ICD-10 codes for thyroid nodules and thyroid cancer from January 2017 until May 2021.

RESULTS

We analyzed 183 patients with thyroid nodules. The mean patient age was 14 years (interquartile range 11-16) with a female (79.2 %) and white Caucasian (78.1 %) predominance. The overall DTC in our pediatric patient cohort was 12.6 % (23 out of 183). Most of the malignant nodules measured from 1-4 cm (65.2 %) with TI-RADS score of ≥4 (69.6 %). Among the fine-needle aspiration results (n=49), the highest frequency of DTC was within the malignant category (16.33 %), followed by suspicious for malignancy (6.12 %), then atypia or follicular lesion of undetermined significance (8.16 %), and lastly follicular lesion or neoplasm and benign with 4.08 % and 2.04 % respectively. Of the forty-four thyroid nodules that underwent surgical intervention, pathology was remarkable for 19 papillary thyroid carcinoma (43.18 %) and 4 follicular thyroid carcinoma (9.09 %).

CONCLUSIONS

Based on the analysis of our pediatric cohort in the southeast region at a single institution, adoption of the 2015 ATA guidelines could lead to an increased accuracy in detecting DTC while reducing the number of patients requiring interventions, such as FNA biopsy and/or surgeries. Further, based on our small cohort, it would be reasonable for thyroid nodules 1 cm or less to be monitored clinically with physical exam and ultrasonography, with further therapeutic or diagnostic intervention considered based on concerning features or parental shared decision making.

Incidence, Recurrence and Mortality Among Filipinos With Differentiated Thyroid Cancer: A Systematic Review

Background

The majority of thyroid malignancies are differentiated thyroid carcinomas (DTCs). We examined the incidence, disease extent, recurrence and disease-specific mortality (DSM) of DTC among Filipinos residing in the Philippines and Filipino immigrants.

Methodology

In accordance with the 2020 PRISMA statement, we performed a systematic literature search in MEDLINE, Google Scholar, EBSCO, Cochrane and Clinicaltrials.gov for the period January 1, 1980 until January 27, 2022. Pooled incidence rate ratio and pooled proportions of disease extent, recurrence and DSM were determined.

Results

Literature search yielded 1,852 studies. Out of 26 articles retrieved, nine retrospective case controls and cohorts were included. Incidence of DTC was significantly higher in female Filipino immigrants compared with non-Hispanic whites (NHW). Distant metastases and recurrence were more common among Filipinos and Filipino immigrants compared with NHW. Limited data showed higher DSM in Filipino immigrants and NHW than Filipinos, which may be influenced by reporting bias.

Conclusions

This review supports the trend of increased incidence and recurrence of DTC among Filipinos, although case registries are essential to confirm these findings. In the setting of the newly released Philippine guidelines for DTC, prospective studies with active long-term follow-up will help detect any changes in the outcomes of DTC among Filipinos.

Clinical and Sonographic Features of Noninvasive Follicular Thyroid Neoplasm With Papillary-Like Nuclear Features: A Retrospective Study

ABSTRACT

This study was designed to investigate the clinical and sonographic features of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTPs) as compared with classical papillary thyroid carcinoma (cPTC), follicular adenoma (FA), and follicular thyroid carcinoma (FTC). A total of 178 patients were enrolled in this study. The clinical characteristics and sonographic features of thyroid nodules were compared between NIFTP and cPTC or FA/FTC. All nodules were reclassified according to the Thyroid Ultrasound Imaging Reporting and Data System and American Thyroid Association guidelines classification. The mean size of NIFTP was 29.91 ± 14.71 mm, which was larger than that of cPTC ( P = 0.000). Significant difference was found in lymph node metastases between NIFTP and cPTC ( P = 0.000). Most NIFTPs showed solid composition, hypoechoic echogenicity, smooth margin, wider than tall shape, none echogenic foci, absence of halo, and perinodular vascularity, which were similar with FA and FTC. Compared with NIFTP, hypoechoic and very hypoechoic, taller than wide, irregular margin, punctate echogenic foci, absence of halo, and low vascularity were more commonly observed in cPTC. There were statistical differences both in American College of Radiology Thyroid Ultrasound Imaging Reporting and Data System and in American Thyroid Association classification between NIFTP and cPTC ( P < 0.05), but there were no significant differences between NIFTP and FTC/FA ( P > 0.05). The ultrasonographic characteristics of NIFTP were obviously different from cPTC but overlapped with FTC and FA. Ultrasound could help increase preoperative attention of NIFTP in an appropriate clinical setting, which may lead to a more conservative treatment approach.

Case report: skeletal muscle metastasis from follicular thyroid carcinoma presenting as synovial sarcoma

Differentiated thyroid carcinomas tend to remain localized and usually are of slow progression with excellent long-term survival. The major sites of distant metastases are cervical lymph nodes, lungs and bones and the minor sites include the brain, liver, pericardium, skin, kidney, pleura and muscle. Skeletal muscle metastases from differentiated thyroid carcinoma, are exceedingly rare. In this report, a 42-year-old woman with follicular thyroid cancer that had had a total thyroidectomy and radioiodine ablation nine years ago was presented with a painful right thigh mass and negative PET/CT scan. The patient had also lung metastases during the follow-up period which were treated with surgery, chemotherapy and radiation therapy. An MRI scan of the right thigh showed a deep-seated lobulated mass with cystic regions, bleeding elements and strong heterogeneous post contrast administration enhancement. Due to the similarities in clinical manifestations and imaging features between soft tissue tumors and skeletal muscle metastases, the case was initially misdiagnosed in favor of synovial sarcoma. Histopathological, immunohistochemistry and molecular analysis of the soft tissue mass confirmed to be a thyroid metastasis and, as a result, a final diagnosis of skeletal muscle metastasis was provided. Even though the probability of a skeletal muscle metastasis from thyroid cancer approaches zero, this study aims to raise the awareness to the medical community that these events do in fact occur in the clinical setting and should be considered in the differential diagnosis of patients with thyroid carcinomas.

A Rare Case of Scalp Metastasis from Encapsulated Angioinvasive Follicular Thyroid Carcinoma

Cutaneous metastases from thyroid carcinomas are extremely rare; however, the scalp is a common site for cutaneous metastases from follicular thyroid carcinomas (FTCs). We report the case of a 77-year-old male patient with a blood-rich scalp lesion. Histopathological tests of punch biopsy specimens revealed subcutaneous well-formed follicular structures that were similar to those found in the thyroid gland. Immunohistochemistry using thyroid transcription factor-1 (TTF-1) and paired-box gene family 8 (PAX8) revealed an FTC metastasis. We performed total thyroidectomy and resection of the scalp lesion at the same time and administered postoperative radioactive iodine treatment. The primary thyroid lesion was diagnosed as an FTC based on extracapsular extension and vessel invasion. The patient has not experienced disease recurrence since the treatment. When scalp metastasis of thyroid carcinoma is suspected, we recommend total extirpation, including the primary tumor and scalp metastasis, for an improved prognosis.

Delayed Presentation of Functioning Metastasis in a Patient with Follicular Thyroid Carcinoma

Functioning metastases from differentiated thyroid carcinoma are rare and present a great therapeutic challenge. Here, we present an unusual case of a patient with metastatic thyroid carcinoma who developed a hyperthyroid state a few years after the diagnosis due to functioning metastases. Radioiodine treatment was effective in controlling the hyperthyroidism; however, it had no effect on tumor burden. By sharing our experience with this case, we hope to raise awareness for this rare condition and the ways to manage it.

Comparison of the diagnostic performance of three ultrasound thyroid nodule risk stratification systems for follicular thyroid neoplasm: K-TIRADS, ACR -TIRADS and C-TIRADS

OBJECTIVE

To explore the diagnostic performance of the currently used ultrasound-based thyroid nodule risk stratification systems (K-TIRADS, ACR -TIRADS, and C-TIRADS) in differentiating follicular thyroid adenoma (FTA) from follicular thyroid carcinoma (FTC).

METHODS

Clinical data and preoperative ultrasonographic images of 269 follicular thyroid neoplasms were retrospectively analyzed. All of them were detected by Color Doppler ultrasound instruments equipped with high-frequency liner array probes (e.g. Toshiba Apoli500 with L5-14MHZ; Philips IU22 with L5-12MHZ; GE LOGIQ E9 with L9-12MHZ and MyLab Class C with L9-14MHZ). The diagnostic performance of three TIRADS classifications for differentiating FTA from FTC was evaluated by drawing the receiver operating characteristic (ROC) curves and calculating the cut-off values.

RESULTS

Of the 269 follicular neoplasms (mean size, 3.67±1.53 cm), 209 were FTAs (mean size, 3.56±1.38 cm) and 60 were FTCs (mean size, 4.07±1.93 cm). There were significant differences in ultrasound features such as margins, calcifications, and vascularity of thyroid nodules between the FTA and FTC groups (P < 0.05). According to the ROC curve comparison analysis, the diagnostic cut-off values of K-TIRADS, ACR-TIRADS, and C-TIRADS for identifying FTA and FTC were K-TR4, ACR-TR4, and C-TR4B, respectively, and the areas under the curves were 0.676, 0.728, and 0.719, respectively. The difference between ACR-TIRADS and K-TIRADS classification was statistically significant (P = 0.0241), whereas the differences between ACR-TIRADS and C-TIRADS classification and between K-TIRADS and C-TIRADS classification were not statistically significant (P > 0.05).

CONCLUSION

The three TIRADS classifications were not conducive to distinguishing FTA from FTC. It is necessary to develop a novel malignant risk stratification system specifically for the identification of follicular thyroid neoplasms.

Differentiated thyroid carcinoma: An update

Differentiated thyroid carcinoma (DTC) is the most common endocrine cancer. Particularly the incidence of small clinically indolent tumors has been increasing significantly during the last decades because of increased diagnostic scrutiny, while the DTC-related mortality remained unchanged. In light of the increased awareness of the significant risk of detecting clinically indolent tumors and the potential harm and burden associated with overly diagnosis and the treatment, the approach towards management of DTC recently underwent a critical appraisal. The focus lays on reducing the unnecessary burden for patients with very low risk DTC and the correct identification of those who require treatment that is more intensive and/or follow-up. Management of DTC includes a range of different modalities, making multidisciplinary collaboration expedient. In this review, we elaborate on the recent developments in diagnosis, staging and management of DTC with specific focus on the more individualized risk assessment-based approach.

Machine learning algorithms are comparable to conventional regression models in predicting distant metastasis of follicular thyroid carcinoma

OBJECTIVE

Distant metastasis often indicates a poor prognosis, so early screening and diagnosis play a significant role. Our study aims to construct and verify a predictive model based on machine learning (ML) algorithms that can estimate the risk of distant metastasis of newly diagnosed follicular thyroid carcinoma (FTC).

DESIGN

This was a retrospective study based on the Surveillance, Epidemiology, and End Results (SEER) database from 2004 to 2015.

PATIENTS

A total of 5809 FTC patients were included in the data analysis. Among them, there were 214 (3.68%) cases with distant metastasis.

METHOD

Univariate and multivariate logistic regression (LR) analyses were used to determine independent risk factors. Seven commonly used ML algorithms were applied for predictive model construction. We used the area under the receiver-operating characteristic (AUROC) curve to select the best ML algorithm. The optimal model was trained through 10-fold cross-validation and visualized by SHapley Additive exPlanations (SHAP). Finally, we compared it with the traditional LR method.

RESULTS

In terms of predicting distant metastasis, the AUROCs of the seven ML algorithms were 0.746-0.836 in the test set. Among them, the Extreme Gradient Boosting (XGBoost) had the best prediction performance, with an AUROC of 0.836 (95% confidence interval [CI]: 0.775-0.897). After 10-fold cross-validation, its predictive power could reach the best [AUROC: 0.855 (95% CI: 0.803-0.906)], which was slightly higher than the classic binary LR model [AUROC: 0.845 (95% CI: 0.818-0.873)].

CONCLUSIONS

The XGBoost approach was comparable to the conventional LR method for predicting the risk of distant metastasis for FTC.

The potential value of LC-MS non-targeted metabonomics in the diagnosis of follicular thyroid carcinoma

Background

To explore the metabolic differences of follicular thyroid carcinoma (FTC) by metabonomics, to find potential biomarkers for the diagnosis of FTC, and to explore the pathogenesis and diagnosis and treatment strategies of FTC.

Method

The metabonomics of 15 patients with FTC and 15 patients with follicular thyroid nodules(FTN) treated in Henan Cancer Hospital were analyzed by liquid chromatography-mass spectrometry (LC-MS).

Results

The analysis showed that the metabolite profiles of FTC tissues could be well distinguished from those of control tissues, and 6 kinds of lipids were identified respectively, including lysophosphatidic acid(LysoPA) [LysoPA(0:0/18:0),LysoPA(0:0/18:2(9Z,12Z)],LysoPA[20:4(8Z,11Z,14Z,17Z)/0:0)]; phosphatidic acid(PA) [PA(20:3(8Z,11Z,14Z)/0:0),PA(20:4(5Z,8Z,11Z,14Z)/0:0),PA(20:5(5Z,8Z,11Z,14Z,17Z)/0:0)]; lysophosphatidylcholine(LPC) [LPC(18:1),LPC(16:0),LPC[16:1(9Z)/0:0],LPC(17:0),LPC[22:4(7Z,10Z,13Z,16Z),LPC(20:2(11Z,14Z); phosphatidylcholine(PC)(PC(14:0/0:0),PC(16:0/0:0); sphingomyelin(SM) (d18:0/12:0); fatty acid(FA)(18:1(OH3)]. There are 2 kinds of amino acids, including L-glutamate,L-glutamine.There are 3 other metabolites, including retinol,flavin adenine dinucleotide,androsterone glucuronide.Lipid metabolites are the main metabolites in these metabolites.The metabolic pathways related to FTC were analyzed by KEGG and HMDB, and 9 metabolic pathways were found, including 4 amino acid related metabolic pathways, 1 lipid metabolic pathways and 4 other related pathways.

Conclusion

There are significant differences in many metabonomic characteristics between FTC and FTN, suggesting that these metabolites can be used as potential biomarkers. Further study found that LysoPA and its analogues can be used as biomarkers in the early diagnosis of FTC.It may be related to the abnormal metabolism of phospholipase D (PLD), the key enzyme of LysoPA synthesis caused by RAS pathway. At the same time, it was found that the metabolic pathway of amino acids and lipids was the main metabolic pathway of FTC. The abnormality of LysoPA may be the cause of follicular tumor carcinogenesis caused by lipid metabolic pathway.

The Role of Claudin-1 Expression in Follicular and Papillary Thyroid Neoplasm

OBJECTIVE

This study evaluated differences in Claudin-1 expression between follicular adenoma (FA), follicular thyroid carcinoma (FTC), follicular variant papillary thyroid carcinoma (FV-PTC), and papillary thyroid carcinoma (PTC).

MATERIAL AND METHODS

This study used a cross-sectional approach. Immunostaining using the polyclonal antibody Claudin-1 was performed on 75 samples divided into 20 samples for follicular adenoma, follicular thyroid carcinoma, papillary carcinoma, and 15 samples of follicular variant thyroid carcinoma, respectively.

RESULTS

Claudin-1 expression is detected on the cytoplasmic membrane of tumor cells and appears to be varied among thyroid neoplasms. The claudin-1 expression score revealed a statistically significant difference between FA against FV-PTC, FA versus (vs) PTC, and FTC vs PTC, with median values of 4 vs 6 (p = 0.016), 4 vs 8 (p = 0.001), and 5 vs 8 (p = 0.002), respectively. However, there was no statistically significant difference in scores between the FA and the FTC (4 vs 5), or between the FTC and the FV-PTC groups (5 vs 6 (p=1,000).

CONCLUSION

These results suggest that Claudin-1 may be capable of discriminating follicular adenoma from classic and follicular variant of papillary thyroid carcinoma. It can also differentiate follicular thyroid carcinoma and papillary thyroid carcinoma, especially for cases challenging to assess by hematoxylin and eosin staining. It still holds promise in providing targeted cancer therapy.

Clinical outcomes of a cohort of 271 patients with lung metastases from differentiated thyroid carcinoma

CONTEXT

Lung is the most common site of distant metastases from differentiated thyroid carcinoma (DTC).

OBJECTIVE

To investigate the outcomes of a cohort of patients with DTC and lung metastases (LM).

METHODS

A retrospective analysis of a cohort of 271 patients with LM was performed.

RESULTS

The female-to-male ratio was 1:1 and the median follow-up time was 5.9 (1.1-38.4) years. Papillary thyroid carcinoma (PTC) was the most frequent type (83.4%), mainly the classic variant, followed by follicular thyroid carcinoma (FTC, 10.3%) and Hürthle cell carcinoma (HTC, 6.3%). The prevalence of PTC, FTC and HCC was different between the micronodular and macronodular LM groups [87.4%, 6.3% and 6.3% vs. 74.6%, 19.0% and 6.3%, respectively (p = .013)]. Only 5.0% of the patients had LM diagnosed after a period of remission. LM were submitted to radioactive iodine treatment (RAIT) in 84.5% (52.8% showed ¹³¹ iodine avid metastases). Complete remission was only achieved in 12.2%. Micronodular disease and age <55 years at LM diagnosis were associated with a better prognosis (p < .05). We found no difference in survival between patients with LM treated or not with RAIT. However, in patients submitted to RAIT, there was a tendency for longer survival in the group of patients with ¹³¹ I avid lesions.

CONCLUSION

The classic variant of PTC was the most frequent histology found in LM of DTC. LM are rarely diagnosed in the follow-up when complete remission is achieved after surgery and ¹³¹ I. Younger age at LM diagnosis and a micronodular pattern are associated with a better prognosis.

Improve follicular thyroid carcinoma diagnosis using computer aided diagnosis system on ultrasound images

OBJECTIVE

We aim to leverage deep learning to develop a computer aided diagnosis (CAD) system toward helping radiologists in the diagnosis of follicular thyroid carcinoma (FTC) on thyroid ultrasonography.

METHODS

A dataset of 1159 images, consisting of 351 images from 138 FTC patients and 808 images from 274 benign follicular-pattern nodule patients, was divided into a balanced and unbalanced dataset, and used to train and test the CAD system based on a transfer learning of a residual network. Six radiologists participated in the experiments to verify whether and how much the proposed CAD system helps to improve their performance.

RESULTS

On the balanced dataset, the CAD system achieved 0.892 of area under the ROC (AUC). The accuracy, recall, precision, and F1-score of the CAD method were 84.66%, 84.66%, 84.77%, 84.65%, while those of the junior and senior radiologists were 56.82%, 56.82%, 56.95%, 56.62% and 64.20%, 64.20%, 64.35%, 64.11% respectively. With the help of CAD, the metrics of the junior and senior radiologists improved to 62.81%, 62.81%, 62.85%, 62.79% and 73.86%, 73.86%, 74.00%, 73.83%. The results almost repeated on the unbalanced dataset. The results show the proposed CAD approach can not only achieve better performance than radiologists, but also significantly improve the radiologists' diagnosis of FTC.

CONCLUSIONS

The performances of the CAD system indicate it is a reliable reference for preoperative diagnosis of FTC, and might assist the development of a fast, accessible screening method for FTC.

The differences in distant metastatic patterns and their corresponding survival between thyroid cancer subtypes

INTRODUCTION

This study aimed to systematically elucidate the metastatic patterns and their corresponding survival of each thyroid cancer subtype at time of diagnosis.

METHODS

We accessed the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2018 to search for primary thyroid cancers with DM at presentation (M1).

RESULTS

We included 2787 M1 thyroid cancers for statistical analyses and the incidence of DM at presentation was 2.4%. Lung was the most common metastatic site for anaplastic thyroid carcinoma (ATC), poorly differentiated thyroid carcinoma (PDTC), papillary thyroid carcinoma (PTC), and oncocytic (Hurthle) cell carcinoma (HCC) whereas bone is the favorable disseminated site of follicular thyroid carcinoma (FTC) and medullary thyroid carcinoma (MTC). Patients with multi-organ metastases had the worst survival whereas bone metastases were associated with a favorable outcome (p < 0.001).

CONCLUSION

There are significant differences in DM patterns of thyroid cancer subtypes and their corresponding survival.

VsN, a Reliability-index of Shear-wave Measurement in Sonoelastography, Is Useful for the Diagnosis of Thyroid Tumor Malignancy

BACKGROUND/AIM

Shear wave measurement (SWM) is a new elastography modality that quantifies the shear wave velocity (Vs) and the percentage of the net effective shear wave velocity (VsN). This study examined whether these parameters could be used to differentiate between malignant and benign thyroid tumors.

PATIENTS AND METHODS

The study of SWM enrolled 111 patients (133 nodules) who underwent thyroid surgery. Overall, 61 nodules were diagnosed as benign and 72 as malignant, of which 68 nodules were diagnosed as papillary thyroid carcinoma (PTC) and 4 as follicular thyroid carcinoma (FTC).

RESULTS

A preoperative SWM revealed that Vs was significantly higher and VsN significantly lower in the PTC compared to the benign nodules. The VsN of FTC was significantly lower than that of follicular adenoma. Multivariate analysis revealed that VsN significantly correlated with nodule malignancy.

CONCLUSION

SWM parameters, especially VsN, can potentially differentiate between benign and malignant thyroid nodules non-invasively.

Proteotypic Differences of Follicular-Patterned Thyroid Neoplasms

The diagnosis of follicular-patterned thyroid tumors such as follicular thyroid adenoma (FA), follicular thyroid carcinoma (FTC), and follicular variant of papillary thyroid carcinoma (FvPTC) remains challenging. This study aimed to explore the molecular differences among these three thyroid tumors by proteomic analysis. A pressure cycling technology (PCT)-data-independent acquisition (DIA) mass spectrometry workflow was employed to investigate protein alterations in 52 formalin-fixed paraffin-embedded (FFPE) specimens: 18 FA, 15 FTC, and 19 FvPTC specimens. Immunohistochemical (IHC) analysis of 101 FA, 67 FTC, and 65 FvPTC specimens and parallel reaction monitoring (PRM) analysis of 20 FA, 20 FTC, and 20 FvPTC specimens were performed to validate protein biomarkers. A total of 4107 proteins were quantified from 52 specimens. Pairwise comparisons identified 287 differentially regulated proteins between FTC and FA, and 303 between FvPTC and FA and 88 proteins were co-dysregulated in the two comparisons. However, only 23 discriminatory proteins between FTC and FvPTC were detected. Additionally, the quantitative results for ANXA1 expression based on IHC staining and PRM-MS quantification were consistent with the proteomic results, showing that ANXA1 can be used to distinguish FvPTC from FA and FTC. The differentially regulated proteins found in this study can differentiate FA from FvPTC. In addition, ANXA1 is a promising biomarker for differentiating FvPTC from the other thyroid tumors.

Follicular thyroid carcinoma metastasizing to rare sites and exhibiting variable inter-lesional heterogeneity on 18F-fluorodeoxyglucose positron emission tomography/computed tomography and 131I

A patient of differentiated follicular thyroid carcinoma with unusual sites of metastases is illustrated with ¹³¹I and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) imaging findings. The described case harbored extremely rare metastasis to the urinary bladder with multi-organ metastatic disease (including unusual sites of right bronchus and hepatic metastases). There was inter-lesional heterogeneity among the metastatic lesions with regard to the ¹³¹I and FDG uptake in the aforementioned lesions. The detection of such heterogeneity has important implications for patient management in metastatic differentiated thyroid carcinoma.

Development and Validation of an Ultrasonic Diagnostic Model for Differentiating Follicular Thyroid Carcinoma from Follicular Adenoma

Background

High-resolution ultrasound is the first choice for the diagnosis of thyroid nodules, but it is still difficult to distinguish between follicular thyroid carcinoma (FTC) and follicular adenoma (FA). Our research aimed to develop and validate an ultrasonic diagnostic model for differentiating FTC from FA.

Methods

This study retrospectively analyzed 196 patients who were diagnosed as FTC (n=83) and FA (n=113). LASSO regression analysis was used to screen clinical and ultrasonic features. Multivariate logistic regression analysis was used to establish the ultrasonic diagnostic model of FTC. Nomogram was used for the visualization of diagnostic models. C-index, ROC, and calibration curves analysis were used to evaluate the accuracy of the diagnostic model. Decision curve analysis (DCA) was used to evaluate the net benefits of the ultrasonic diagnostic model for FTC diagnosis under different threshold probabilities. The bootstrap method was used to verify the ultrasonic diagnostic model.

Results

After Lasso regression analysis, 10 clinical and ultrasonic features were used to construct the ultrasonic diagnostic model of FTC. The C-index and AUC of the model were 0.868 and 0.860, respectively. DCA showed that the ultrasonic model had good clinical application value. The C-index in the validation group was 0.818, which was close to the C-index in the model.

Conclusion

Ultrasonic diagnostic model constructed with 10 clinical and ultrasonic features can better distinguish FTC from FA.

Thyroid Follicular Epithelial Cell-Derived Cancer: New Approaches and Treatment Strategies

Thyroid follicular epithelial cell-derived cancer includes papillary carcinoma, follicular carcinoma, Hürthle cell carcinoma, poorly differentiated thyroid cancer, and anaplastic thyroid carcinoma. Although the incidence of thyroid cancer has increased over the past 30 years, there has not been a significant increase in patient mortality. Use of increasingly sensitive detection methods such as high-resolution imaging has enabled earlier detection and better characterization of the thyroid malignancies. In the past several years, researchers have evaluated genetic mutations promoting thyroid carcinogenesis and oncogenesis. The identification of genetic mutations is important in understanding tumor initiation and progression. Additionally, these identified mutations may also serve as potential diagnostic or prognostic indicators and therapeutic molecular targets.

Follicular Thyroid Carcinoma in a Developing Country: A 10-Year Retrospective Study

Background The most common endocrine tumor is thyroid cancer. Follicular thyroid carcinoma (FTC) accounts for 5-10% of all thyroid cancers. Patients with FTC frequently present with more advanced diseases and a higher occurrence of distant metastases because of the propensity of vascular invasion. FTC is mainly treated with surgery while radioactive iodine (RAI) therapy is the main adjuvant therapy according to the American Thyroid Association guidelines. Methodology This was a retrospective observational study of FTC patients aged 18 and above conducted at a tertiary care hospital in Karachi from January 01, 2010 to December 31, 2019. Results A total of 404 patients with thyroid carcinoma were sorted, of which 40 (10.1%) were FTC cases. Overall, 50% of the patients were in the age group of 41-60 years, and the female-to-male ratio was 1.5:1. The majority of patients (60%) presented with neck swelling, followed by bone and lung metastasis in 20% and compressive symptoms in another 20%. On fine needle aspiration cytology (FNAC), 50% had Bethesda category III-IV nodules while 10% had Bethesda category II. Overall, 50% had a total thyroidectomy while 50% had a lobectomy followed by a completion thyroidectomy. On histopathology, 23 (57.5%) patients had minimally invasive FTC while 17 (42.5%) had widely invasive FTC. A total of 17 (42.5%) patients had received RAI 30-100 mCi while 10 (25%) received more than 100 mCi. Conclusions FTC can present with both local or metastatic symptoms. The atypical presentation of metastatic FTC should be considered, diagnosed, and managed early to limit mortality and morbidity. Ultrasound is the best diagnostic investigation of choice followed by FNAC. Surgery is the mainstay of treatment and should be followed by RAI in select cases. Thus, understanding the trend of FTC and proper planning and utilization of the resources will help developing countries in effectively treating the FTC.

Macrofollicular variant follicular thyroid tumors are DICER1 mutated and exhibit distinct histological features

AIMS

DICER1 germline mutations cause DICER1 syndrome, in which multinodular goitre is a common feature. Recently, somatic DICER1 mutations have been reported in sporadic thyroid carcinomas, of which the newly described macrofollicular variant of follicular thyroid carcinoma (MV-FTC) seems particularly enriched for this aberrancy. We report here histological and genetic findings in five follicular thyroid tumours with macrofollicular architecture (four carcinomas and one adenoma).

METHODS AND RESULTS

We have diagnosed five cases during a year-long period at the Karolinska University Hospital, a tertiary thyroid cancer center with a catchment area of approximately 2.3 million inhabitants. Tumour DNA was interrogated using a commercially available massive parallel sequencing platform. All cases were female patients, ranging from 13 to 33 years at surgery. A single patient was a DICER1 syndrome carrier; the others were sporadic cases. All tumours displayed a macrofollicular architecture with a broad capsule. The MV-FTCs displayed capsular invasion, but never vascular invasion. Areas with degenerative changes (microinfarctions) were noted in all cases, and focal papillary growth was observed in the majority. The Ki-67 proliferation index was always above 4%. All cases displayed DICER1 gene mutations, of which four of five cases displayed RNase IIIb hot-spot missense mutations adjoined by a second, deleterious variant in three of five tumouurs.

CONCLUSIONS

Macrofollicular variants of follicular thyroid tumours are predominantly found in younger females and are strongly linked to somatic DICER1 gene mutations. Histological features such as a broad tumorous capsule, focal infarctions and areas with papillae could constitute clues prompting further genetic analyses.

The Value of Sonography in Distinguishing Follicular Thyroid Carcinoma from Adenoma

Purpose

Differentiation between follicular thyroid carcinomas (FTCs) and follicular thyroid adenomas (FTAs) is difficult and the sonographic features of FTC are not yet fully established. The purpose of this study is to explore the sonographic features of FTC and the value of sonography in differentiating FTCs from FTAs.

Patients and Methods

A total of 28 pathologically proven FTCs and 53 FTAs in 78 patients who were performed thyroid surgery were included in this retrospective study. The sonographic features of each tumor including an interrupted halo, satellite nodule(s) with or without halo ring, local irregularity of margin and cluster of grapes sign were evaluated. A mode image of FTC halo was built up in our study. The frequencies of the sonographic features were compared by chi-square test or Fisher exact test between FTCs and FTAs. The relative risk of malignancy was assessed by logistic regression analysis.

Results

Logistic regression analysis showed that a thick, irregular and/or interrupted halo with or without satellite nodule(s), hypoechoic or marked hypoechoic echogenicity, a predominantly solid pattern, cluster of grapes sign, micro-or macro-calcifications, rim calcifications correlated with significant increases in relative risk for FTCs (odds ratio 11.48 (1.37-96.56), 6.74 (1.05-43.30), 17.51 (1.78-172.53), 9.55 (1.44-63.46), 9.36 (1.25-70.15) and 17.45 (1.04-292.65), respectively, p<0.05). Two new sonographic features, an interrupted halo and satellite nodule(s) with or without halo ring, can only be found in FTCs.

Conclusion

An interrupted halo and satellite nodule(s) with or without halo ring are specific sonographic features for FTCs. Sonography could play a role in differentiating follicular thyroid carcinoma from adenoma.

Follicular Thyroid Carcinoma with Unusual Radioiodine-Refractory Breast Metastasis Mimicking Primary Breast Malignancy

The breast is an unusual site for metastasis from malignant tumors, although it may be the first manifestation of an extramammary primary malignancy typically arising in the lung, skin (melanoma), ovary, or lymph nodes (lymphoma). Breast metastasis from thyroid carcinoma is extremely rare and may take years to develop, as differentiated thyroid carcinoma is usually indolent and slow-growing and metastasizes to the lymph nodes, lungs, and bones. Here, we present the case of a middle-aged woman (after subtotal thyroidectomy for multinodular goiter 24 y previously) showing discordant ¹⁸F-FDG and iodine avidity in proven metastatic disease involving the lymph nodes, bones, spleen, and breast on whole-body ¹³¹I and ¹⁸F-FDG scans due to tumor heterogeneity.

Additional Tissue Sampling Trials Did Not Change Our Thyroid Practice

Simple Summary

Some studies have suggested that the use of additional tissue blocks to diagnose follicular thyroid carcinoma (FTC) could increase the accuracy of diagnosis and improve prognosis, and entire capsule sampling was recommended for a definitive diagnosis of borderline thyroid tumors in 2016. We conducted a study in 2016 to examine whether additional tissue sampling of the encapsulated follicular tumor increases the diagnosis of malignant cases in our patient cohort. Furthermore, the diagnosis was reclassified according to the 4th edition of the World Health Organization’s classification system. The additional tissue sampling only had a slight impact on our thyroid practice and resulted in no benefits to the patient; therefore, we decided to cease it.

Abstract

This study aimed to determine whether additional tissue sampling of encapsulated thyroid nodules would increase the frequency of follicular thyroid carcinoma (FTC) diagnoses. We examined thyroid tissue specimens from 86 patients suspected of FTC (84.9% female; mean age, 49.0 ± 17.8 years). The number of tissue blocks created for pathological assessments ranged from 3 to 20 (mean, 9.1 ± 4.1); the numbers in the previous method recommended by the Japanese General Rules for the Description of Thyroid Cancer and additional blocks ranged from 1 to 12 (mean, 6.0 ± 2.8) and from 1 to 8 (mean, 3.1 ± 2.0), respectively. The additional blocks were subsequently examined to determine whether any diagnoses changed from those based on the previous method. Five patients were diagnosed with FTC using the previous method; however, additional tissue blocks led to the diagnosis of FTC in 6 patients, as 1 diagnosis was revised from follicular adenoma to FTC. It has been reported that increasing the number of tissue blocks used for pathological assessments can increase the frequency of FTC diagnoses; however, this was not clinically significant in thyroid carcinoma, which requires completion thyroidectomy and radioactive iodine treatment. It resulted in no benefits to the patient because all minimally invasive FTCs, follicular tumors of uncertain malignant potential (FT-UMP), and follicular adenomas are treated with lobectomy alone in Japan. Additional tissue sampling only had a slight impact on our thyroid practice; therefore, we decided to cease it.

Late Onset of an Overlooked Follicular Thyroid Carcinoma Presenting as a Chest Wall Tumor 10 Years Following Thyroidectomy

Objective

Metastatic chest wall tumors resulting from thyroid carcinomas are not unusual; however, the late onset of metastasis of a follicular thyroid carcinoma (FTC) is extremely rare. We aim to present a report of a case with chest wall metastasis of an FTC 10 years following thyroidectomy.

Methods

Among the studies performed were chest wall tumor imaging, serum thyroid stimulating hormone determination, and histopathology of the chest wall tumor and thyroid tissue examination.

Results

An asymptomatic 28-year-old woman was noted to have a left-sided chest wall mass on a chest X-ray performed for a job application. She had a history of right hemithyroidectomy 10 years prior to her admission, which had been reported as a thyroid follicular adenoma. Computed tomography showed a tumor measuring 75 × 50 mm in diameter localized at the left paravertebral region. The maximum standardized uptake value of the tumor was seven in positron emission tomography. Histopathologic finding of the trucut biopsy of the chest wall tumor revealed metastasis of a differentiated thyroid carcinoma. The patient underwent a completion left hemithyroidectomy with chest wall resection and reconstruction. Previous right hemithyroidectomy material was examined and diagnosed as minimally invasive FTC. Histopathologic finding of the resected chest wall tumor was consistent with metastasis of an FTC.

Conclusions

Although extremely rare, the late metastasis of a thyroid carcinoma should be considered in the differential diagnosis of patients with chest wall tumors who have a previous history of thyroidectomy even with a diagnosis of benign tumor.

Actions of Thyroid Hormones on Thyroid Cancers

L-Thyroxine (T4) is the principal ligand of the thyroid hormone analogue receptor on the extracellular domain of integrin αvβ3. The integrin is overexpressed and activated in cancer cells, rapidly dividing endothelial cells, and platelets. The biologic result is that T4 at physiological concentration and without conversion to 3,3',5-triiodo-L-thyronine (T3) may stimulate cancer cell proliferation and cancer-relevant angiogenesis and platelet coagulation. Pro-thrombotic activity of T4 on platelets is postulated to support cancer-linked blood clotting and to contribute to tumor cell metastasis. We examine some of these findings as they may relate to cancers of the thyroid. Differentiated thyroid cancer cells respond to physiological levels of T4 with increased proliferation. Thus, the possibility exists that in patients with differentiated thyroid carcinomas in whom T4 administration and consequent endogenous thyrotropin suppression have failed to arrest the disease, T4 treatment may be stimulating tumor cell proliferation. In vitro studies have shown that tetraiodothyroacetic acid (tetrac), a derivative of T4, acts via the integrin to block T4 support of thyroid cancer and other solid tumor cells. Actions of T4 and tetrac or chemically modified tetrac modulate gene expression in thyroid cancer cells. T4 induces radioresistance via induction of a conformational change in the integrin in various cancer cells, although not yet established in thyroid cancer cells. The thyroid hormone receptor on integrin αvβ3 mediates a number of actions of T4 on differentiated thyroid cancer cells that support the biology of the cancer. Additional studies are required to determine whether T4 acts on thyroid cancer cells.

Surgical indications and clinical management of benign and malignant follicular thyroid tumors: An algorithmic-based approach

The present study retrospectively reviewed the treatment courses and results of patients with follicular thyroid tumors, including carcinomas. In the 5 year study period from April 2015 to March 2020, 797 patients with differentiated thyroid carcinoma and 128 patients with follicular tumors (FTs) received surgery or treatment for distant metastases and recurrence at the Kanagawa Cancer Center (Japan). Of these patients, 73 that were diagnosed with follicular thyroid carcinoma (FTC) were included in the present study. An algorithm used for the application of treatment strategies was assessed. The aim of the present study was to examine patients with FT or FTC who were treated at the Kanagawa Cancer Center to devise appropriate treatment strategies and to evaluate the various treatment outcomes of FTC. Pre-diagnostic serum thyroglobulin and thyroid stimulating hormone levels, follow-up and overall survival (OS) were investigated in the present study. The results revealed that OS was significantly increased in patients with minimally invasive follicular thyroid cancer (MIFTC) compared with widely invasive follicular thyroid cancer (WIFTC) (log-rank test, P=0.017). Additionally, OS was significantly higher in patients without distant metastasis at the first consultation compared with those initially diagnosed with distant metastasis (log-rank test, P=0.023). Although all patients without distant metastasis at the first consultation and those with MIFTC are alive, the 10-year survival rates were 75.3% for patients with WIFTC and 75.6% for those with distant metastasis at the first consultation. The results of the present study suggested that the prognosis of WIFTC was the worst among patients with FTC and distant metastasis, and that total thyroidectomy surgery and radioactive iodine treatment are essential. Additionally, if the disease progresses, prompt inclusion of tyrosine kinase inhibitor therapy is necessary.

Ultrasonic identification and regression analysis of 294 thyroid follicular tumors

Context

We analyzed the clinical features and ultrasound image features of follicular thyroid carcinoma (FTC) and follicular thyroid adenoma (FTA).

Aims

This study aimed to identify ultrasonographic differences and correlations between FTC and FTA. Meanwhile, ultrasonographic manifestations of thyroid follicular tumor were also retrospectively analyzed.

Settings and Design

Using pathological results as the gold standard, the clinical and ultrasonic image characteristics of FTA and FTC were statistically analyzed, and the differences were analyzed.

Materials and Methods

A total of 304 patients who were diagnosed with FTC or FTA by pathology after thyroidectomy from March 2009 to March 2018 were enrolled in this study. Their ultrasonic images were analyzed; image features were extracted and correlation analyses for these features were conducted. Differences in ultrasonic images between FTC and FTA were also compared.

Statistical Analysis Used

Independent sample t-test; Wilcoxon rank sum test; A Chi-square test: Univariate and multivariate logistic regression analyses.

Results

When performing ultrasound diagnosis, attention should be paid to identify FTC and FTA in terms of age, nodular goiter conditions, nodular boundary conditions, internal echo, calcification, blood flow signals, thyroid imaging reporting and data system (TI-RADS) grading and cystic solidity conditions. Moreover, a multivariate logistic regression showed that the boundaries were unclear, and cystic degeneration, TI-RADS, hypoecho, nodular goiter, macrocalcification and microcalcification were associated with FTC. Among them, macrocalcification is a protective factor for thyroid follicular tumors, and other indicators are risk factors.

Conclusion

Ultrasound can provide valuable information for the identification of follicular neoplasms, but further research in this area is still necessary.

FAM172A promotes follicular thyroid carcinogenesis and may be a marker of FTC

Our aims were to uncover the role of FAM172A (Family with sequence similarity 172 member A) in the pathogenesis of follicular thyroid carcinoma (FTC) and to evaluate its value in the differential diagnosis between malignant and benign thyroid follicular lesions. FAM172A expression was evaluated by q-PCR, immunoblotting and immunohistochemistry (IHC). The ability of proliferation, migration and invasion of cells were assessed by Cell Counting Kit-8 assay (CCK8), clone-formation and Transwell assays. Nude mouse tumorigenicity assays were used to investigate the role of FAM172A in the pathogenesis of FTC in vivo. The value of FAM172A in the differential diagnosis for FTC was assessed using 120 formalin-fixed paraffin-embedded (FFPE) tissues after the operation and 81 fine-needle aspiration biopsy (FNAB) samples before the operation. FAM172A was highly expressed in FTC tissues and FTC cell lines. Downregulation of FAM172A inhibited the proliferation, invasion and migration of FTC cells through Erk1/2 and JNK pathways. Subcutaneous tumorigenesis in nude mice showed that knockdown of FAM172A inhibited tumor growth and progression in vivo. The FAM172A IHC scores of 3.5 had 92% sensitivity and 63% specificity to separate FTC from benign/borderline thyroid follicular lesions, and 92% sensitivity and 80% specificity to discriminate FTC from benign thyroid follicular lesions in postoperative FFPE samples. The corresponding values were 75 and 78%, and 75 and 89% in preoperative FNA samples, respectively. FAM172A plays an important role in the pathogenesis of FTC through Erk1/2 and JNK pathways. FAM172A may be a potential marker for the preoperative diagnosis of FTC based on the IHC results of thyroid FNAB samples.

Synchronous papillary thyroid carcinoma and follicular thyroid carcinoma: case report and review of literature

Collision tumor is a term denoting two histologically distinct tumor types occuring at the same anatomic site, which is a rare clinical entity. In the thyroid gland, collision tumors are rare. Here we report a case of the synchronous occurrence of follicular thyroid carcinoma (FTC) and papillary thyroid carcinoma (PTC). The current case report describes a 40-year-old woman with synchronous FTC and PTC. Pathologists and surgeons should be aware of collision tumors to avoid possible misdiagnosis.

Radioactive Iodine as a Single-Modality Treatment in a Tumor Thrombus Arising from Follicular Thyroid Carcinoma

On rare occasions, differentiated thyroid carcinoma causes tumor thrombosis in the great veins. Multimodality treatment with surgery, radioiodine therapy, and targeted therapies is used to manage tumor thrombosis associated with thyroid malignancies, though no established guidelines exist. We present a woman with a tracer-avid tumor thrombus in the right brachiocephalic vein after surgery for follicular thyroid carcinoma. Follow-up revealed an excellent response after treatment with ¹³¹I as a single modality for both remnant and tumor thrombus.

Brain Metastasis of Follicular Thyroid Carcinoma in Pregnancy: A Case Report and Literature Review

Brain metastases (BMs) related to cancer are quite common and represent the most common brain cancer. We present a rare case of a 32-year-old female, 36 weeks pregnant, admitted to the emergency with complaints of severe headache, vomiting, and left hemiparesis associated with drowsiness. Cranial tomography showed an image suggestive of an expansive lesion in the right front-temporo-insular region with an important mass effect. The result of biopsy with immunohistochemistry was compatible with metastasis of follicular thyroid carcinoma (FTC). The knowledge of neurological characteristics in the clinical analysis of patients with thyroid carcinoma must be highly valued, both in the correct interpretation of the signs and in the early investigation through skull imaging exams.

Radiomics Based on Thyroid Ultrasound Can Predict Distant Metastasis of Follicular Thyroid Carcinoma

We aimed to evaluate whether radiomics analysis based on gray-scale ultrasound (US) can predict distant metastasis of follicular thyroid cancer (FTC). We retrospectively included 35 consecutive FTCs with distant metastases and 134 FTCs without distant metastasis. We extracted a total of 60 radiomics features derived from the first order, shape, gray-level cooccurrence matrix, and gray-level size zone matrix features using US imaging. A radiomics signature was generated using the least absolute shrinkage and selection operator and was used to train a support vector machine (SVM) classifier in five-fold cross-validation. The SVM classifier showed an area under the curve (AUC) of 0.90 on average on the test folds. Age, size, widely invasive histology, extrathyroidal extension, lymph node metastases on pathology, nodule-in-nodule appearance, marked hypoechogenicity, and rim calcification on the US were significantly more frequent among FTCs with distant metastasis compared to those without metastasis (p < 0.05). Radiomics signature and widely invasive histology were significantly associated with distant metastasis on multivariate analysis (p < 0.01 and p = 0.003). The classifier using the results of the multivariate analysis showed an AUC of 0.93. The radiomics signature from thyroid ultrasound is an independent biomarker for noninvasively predicting distant metastasis of FTC.

Treatment Approach to Follicular Thyroid Carcinoma Tumor Thrombus in the Internal Jugular Vein and Brachiocephalic Vein

Thyroid gland carcinoma causing tumor thrombus in the great veins of the neck and mediastinum is a rare condition with poor prognosis. Invasion of the internal jugular vein by thyroid gland carcinoma has been occasionally reported, but tumor thrombi extending to the great veins of the mediastinum are reported extremely rarely. We present a treatment approach in a case of follicular thyroid carcinoma intravascular tumor thrombus in the left internal jugular and left brachiocephalic vein.

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.

Effect of single-nucleotide polymorphism in TERT promoter on follicular thyroid tumor development

Follicular thyroid neoplasm is a common tumor, and consists of follicular thyroid adenoma (FTA) and carcinoma (FTC). The mechanisms of tumor development of FTA and FTC are not well-understood. Single-nucleotide polymorphisms (SNPs) and point mutations in the telomerase reverse transcriptase (TERT) promoter have been associated with tumor development of many cancers. In order to clarify the significance of TERT promoter SNPs and mutations, including rs2853669 (-245T>C), C228T, and C250T, we analyzed 59 FTA patients and 19 FTC patients. Rs2853669 was found in 67.8% (40/59) and 57.9% (11/19) of FTAs and FTCs, respectively, and homozygous rs2853669 (CC) was more frequently found in FTC than in FTA. Furthermore, in FTA, rs2853669 was significantly associated with tumor size greater than 2.0 cm (P < 0.05). C228T was found in 5.1% and 36.8% of FTAs and FTCs, respectively. Frequencies of rs2853669 or/and C228T mutation were 71.2% in FTAs and 73.7%, in FTCs, and were significantly associated with larger tumor sizes in FTAs (P < 0.05). Rs2853669 is considered to be associated with tumor development in FTA and FTC.

Resveratrol Inhibits the Tumorigenesis of Follicular Thyroid Cancer via ST6GAL2-Regulated Activation of the Hippo Signaling Pathway

Follicular thyroid carcinoma (FTC) is a common endocrine malignancy with highly aggressive features. In this study, next-generation sequencing technology was used to identify aberrant expression of sialyltransferase (ST) family members in FTC. Aberrant high expression of alpha-2,6-sialyltransferase 2 (ST6GAL2) was demonstrated to promote tumorigenesis of FTC in vitro and in vivo. Furthermore, ST6GAL2 promoted tumorigenesis by inactivating the Hippo signaling pathway. Resveratrol is a native compound extracted from Vitis species, and many studies have confirmed its protective cardiovascular and antineoplastic effects. Here we found that resveratrol can inhibit the tumorigenesis of FTC by suppressing the expression of ST6GAL2, further activating the Hippo pathway. In summary, this study revealed the role of the ST6GAL2-Hippo signaling pathway in FTC tumorigenesis and indicated that resveratrol, a commonly found antineoplastic compound, could inhibit tumorigenesis of FTC by regulating the abovementioned pathways.

Multidisciplinary Diagnosis of Subcutaneous Soft Tissue Metastasis of Follicular Thyroid Carcinoma: A Case Report

Background: Subcutaneous soft tissue metastasis of follicular thyroid carcinoma (FTC) is rarely diagnosed before surgery for clinicians. Case Report: We present a case of a 67-year-old man with a history of FTC and papillary thyroid microcarcinoma for 5 years. Multiple protruding subcutaneous nodules of the neck were found and removed from the surface of the sternocleidomastoid muscle. Ultrasound, computed tomography and technetium-99 m pertechnetate single-photon emission computed tomography of the neck were performed before the operation, which unfortunately indicated suspicious malignant lesions. Serum Tg was > 300 ng/ml (0.83-68.0 ng/ml), TSH was 36.580 uIU/ml (0.380-4.340 uIU/ml) and AbTg was negative. The pathologic diagnosis was metastatic FTC, invading the surrounding striated muscle, adipose tissue and vessels. Immunohistochemical staining revealed the tumor cells to be positive for thyroglobulin and TTF-1. The specimens of these nodules were further investigated for TERT promoter mutation and the result revealed mutated type (position g 1,295, 228 C>T). Conclusion: Preoperative diagnosis and prognostic prediction of metastatic FTC may be available through a combination of clinical, multimodal imaging and molecular genetic test (viz. multidisciplinary diagnosis). A long-term standardized follow-up is required for patients with a previous diagnosis of FTC.

DNA Methylation-Based Method to Differentiate Malignant from Benign Thyroid Lesions

Background: The differential diagnosis of thyroid nodules using fine-needle aspiration biopsy (FNAB) is challenging due to the inherent limitation of the cytology tests. The use of molecular markers has potential to complement the FNAB-based diagnosis and avoid unnecessary surgeries. In this study, we aimed to identify DNA methylation biomarkers and to develop a diagnostic tool useful for thyroid lesions. Methods: Genome-wide DNA methylation profiles (Illumina 450K) of papillary thyroid carcinoma (PTC = 60) and follicular thyroid carcinoma (FTC = 10) were compared with non-neoplastic thyroid tissue samples (NT = 50) and benign thyroid lesions (BTL = 17). The results were confirmed in publicly available databases from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) using the same DNA methylation platform. Two classifiers were trained to discriminate FTC and PTC from BTL. To increase the applicability of the method, six differentially methylated CpGs were selected and evaluated in 161 thyroid tumors and 69 BTL postsurgical specimens and 55 prospectively collected FNAB using bisulfite-pyrosequencing. Results: DNA methylation analysis revealed 2130 and 19 differentially methylated CpGs in PTC and FTC, respectively. The CpGs confirmed by GEO and TCGA databases showing high areas under the receiver operating characteristic curve in all sample sets were used to train our diagnostic classifier. The model based on six CpGs was able to differentiate benign from malignant thyroid lesions with 94.3% sensitivity and 82.4% specificity. A similar performance was found applying the algorithm to TCGA and GEO external data sets (91.3-97.4% sensitivity and 87.5% specificity). We successfully evaluated the classifiers using a bisulfite-pyrosequencing technique, achieving 90.7% sensitivity and 75.4% specificity in surgical specimens (five of six CpGs). The study comprising FNAB cytology materials corroborated the applicability and performance of the methodology, demonstrating 86.7% sensitivity and 89.5% specificity in confirmed malignant tumors, and 100% sensitivity and 89% specificity in cases with indeterminate cytology. Conclusions: A novel diagnostic tool with potential application in preoperative screening of thyroid nodules is reported here. The proposed protocol has the potential to avoid unnecessary thyroidectomies.

Development and validation of a preoperative prediction model for follicular thyroid carcinoma

OBJECTIVE

The low pre- and intraoperative diagnostic rates in follicular thyroid carcinoma (FTC) often lead to inadequate surgical resection and necessitate further completion surgery. Therefore, the preoperative prediction of FTC in thyroid nodules is essential. DESIGN AND PATIENT: Patients were categorized into two data sets: the modelling data set, which included 3649 patients admitted to our centre between January 2014 and December 2016, and the validation data set, which included 1253 patients admitted between January and December 2017. Patient data from the FTC and non-FTC groups were initially included in a modelling data set to establish a preoperative prediction model. This model was subsequently employed in a validation data set for external validation of the predictive value. The positivity rate for FTC predicted by the model was compared with that of the intraoperative frozen sections.

RESULTS

The preoperative serum thyroglobulin level, nodule diameter, calcification status, solidity and blood supply were selected as predictors for the model. The regression equation was as follows: Y = 0.010 × (thyroglobulin level) + 0.556 × (nodule diameter) + 0.675 × (calcification status) + 2.355 × (nodule component) + 1.072*(blood flow) - 9.787. The model positively predicted FTC at values of Y ≥ -4.11. The accuracy, sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of the prediction model were 89.2%, 90.2%, 87.7%, 39.2 and 0.11, respectively. External validation of the model demonstrated acceptable results. The positive prediction rate of the model was 90.7% (78/86), which was significantly higher than that of the intraoperative frozen sections (10.5% [9/86]; P < 0.0001).

CONCLUSIONS

We successfully established and validated a simple and reliable preoperative prediction model for FTC using the preoperative thyroglobulin level and ultrasonographic features of the thyroid nodules. This model may improve the preoperative evaluation of FTC in clinical settings and facilitate the development of a reasonable surgical programme for FTC.

The surgical dilemma of primary surgery for follicular thyroid neoplasms

Follicular thyroid carcinoma is the second most prevalent form of differentiated thyroid carcinoma, following papillary thyroid carcinoma. Preoperative diagnosis is hampered by the fact that fine-needle aspiration cytology as well as supplemental molecular analysis cannot unambiguously distinguish between follicular thyroid carcinoma and benign follicular thyroid adenoma. The 2017 WHO classification defines three histological subtypes of follicular thyroid carcinoma: minimally invasive (excellent prognosis), encapsulated angioinvasive, and widely invasive type (higher risk of recurrence and metastatic spread). The fact that definite characterization of follicular neoplasms is predominantly a postoperative histological diagnosis (core criteria: capsular, vascular and adjacent tissue invasion) translates into the challenge for the thyroid surgeon to plan preoperatively for presence of malignancy and, if required, to adapt the surgical strategy according to intraoperative (frozen section) or postoperative histological findings. Until improved tools for pre-/intraoperative diagnosis are available, the malignant potential of a follicular thyroid lesion can be assessed by stratifying the patient according to clinical risk factors (presence of metastases, advanced patient age, tumor size). A stepwise, escalating surgical approach with restricted primary resection (hemithyroidectomy) and completion surgery based on the definite histopathology is another option to solve this dilemma. The currently recommended surgical treatment strategies for FTCs as published by ATA, BTA, CAEK and ESES are discussed. There is consensus that prophylactic lymphadenectomy is not required for FTCs and that hemithyroidectomy is sufficient in low-risk FTCs (capsular invasion only) whereas thyroidectomy with postoperative radioiodine therapy is indicated in high-risk FTCs (angioinvasion; widely invasive FTC).

Molecular Signature of Prospero Homeobox 1 (PROX1) in Follicular Thyroid Carcinoma Cells

The prospero homeobox 1 (PROX1) transcription factor is a product of one of the lymphangiogenesis master genes. It has also been suggested to play a role in carcinogenesis, although its precise role in tumour development and metastasis remains unclear. The aim of this study was to gain more knowledge on the PROX1 function in thyroid tumorigenesis. Follicular thyroid cancer-derived cells—CGTH-W-1—were transfected with PROX1-siRNA (small interfering RNA) and their proliferation, cell cycle, apoptosis and motility were then analysed. The transcriptional signature of PROX1 depletion was determined using RNA-Sequencing (RNA-Seq) and the expression of relevant genes was further validated using reverse transcriptase quantitative PCR (RT-qPCR), Western blot and immunocytochemistry. PROX1 depletion resulted in a decreased cell motility, with both migratory and invasive potential being significantly reduced. The cell morphology was also affected, while the other studied cancer-related cell characteristics were not significantly altered. RNA-seq analysis revealed significant changes in the expression of transcripts encoding genes involved in both motility and cytoskeleton organization. Our transcriptional analysis of PROX1-depleted follicular thyroid carcinoma cells followed by functional and phenotypical analyses provide, for the first time, evidence that PROX1 plays an important role in the metastasis of thyroid cancer cells by regulating genes involved in focal adhesion and cytoskeleton organization in tumour cells.