Molecular pathogenesis of euthyroid and toxic multinodular goiter

Functional variants in a TTTG microsatellite on 15q26.1 cause familial nonautoimmune thyroid abnormalities

Insufficient thyroid hormone production in newborns is referred to as congenital hypothyroidism. Multinodular goiter (MNG), characterized by an enlarged thyroid gland with multiple nodules, is usually seen in adults and is recognized as a separate disorder from congenital hypothyroidism. Here we performed a linkage analysis of a family with both nongoitrous congenital hypothyroidism and MNG and identified a signal at 15q26.1. Follow-up analyses with whole-genome sequencing and genetic screening in congenital hypothyroidism and MNG cohorts showed that changes in a noncoding TTTG microsatellite on 15q26.1 were frequently observed in congenital hypothyroidism (137 in 989) and MNG (3 in 33) compared with controls (3 in 38,722). Characterization of the noncoding variants with epigenomic data and in vitro experiments suggested that the microsatellite is located in a thyroid-specific transcriptional repressor, and its activity is disrupted by the variants. Collectively, we presented genetic evidence linking nongoitrous congenital hypothyroidism and MNG, providing unique insights into thyroid abnormalities.

Do extremely large goiters carry a higher risk of malignancy or complications? A case control study

INTRODUCTION

The definition of thyroid goiter remains ambiguous, yet size may impact both malignancy rate and surgical complications' rate.

METHODS

All patients with thyroid goiter who underwent thyroidectomy between 1/2015-1/2023 were included. Goiter was defined as lobe ≥4 cm. For analysis purpose, goiters measuring 4-8 cm and ≥8 cm were defined as large and extremely large goiters, respectively. For malignancy definition, tumor<1 cm in their largest diameter were excluded from study. Collected data included demographics, cytology, histology and postoperative complication.

RESULTS

144 goiters from 111 patients were included. The most common indication for surgery was symptoms (55 %). Compared with large goiter, extremely large goiters demonstrated a trend for tracheal narrowing on pre-operative CT findings (23 % vs. 45 %, p = 0.07 respectively). Overall differentiated thyroid carcinoma (DTC) rate was 17 % (25/144) without statistical difference between groups (p = 0.89). Within goiters with pre-operative benign cytology, the DTC rate was 17 % (7/43). Follicular variant of papillary thyroid cancer was the most common type for both groups. Nodular hyperplasia was significantly associated with extremely large goiters (53 % vs. 73 %, p = 0.03). No significant difference was found in transient hypocalcemia (48 % [15/31] vs. 41 % [5/12], p = 0.6) and other complications' rate between extremely large goiters and the control group.

CONCLUSION

When discussing management options for patients with goiters, the size of the goiter should not regarded as a higher risk for complications or malignancy, yet the relatively high malignancy rate found should be taken under consideration for resection.

Hyperthyroidism

Thyrotoxicosis causes a variety of symptoms and adverse health outcomes. Hyperthyroidism refers to increased thyroid hormone synthesis and secretion, most commonly from Graves' disease or toxic nodular goitre, whereas thyroiditis (typically autoimmune, viral, or drug induced) causes thyrotoxicosis without hyperthyroidism. The diagnosis is based on suppressed serum concentrations of thyroid-stimulating hormone (TSH), accompanied by free thyroxine and total or free tri-iodothyronine concentrations, which are raised (overt hyperthyroidism) or within range (subclinical hyperthyroidism). The underlying cause is determined by clinical assessment, detection of TSH-receptor antibodies and, if necessary, radionuclide thyroid scintigraphy. Treatment options for hyperthyroidism include antithyroid drugs, radioactive iodine, and thyroidectomy, whereas thyroiditis is managed symptomatically or with glucocorticoid therapy. In Graves' disease, first-line treatment is a 12-18-month course of antithyroid drugs, whereas for goitre, radioactive iodine or surgery are preferred for toxic nodules or goitres. Evidence also supports long-term treatment with antithyroid drugs as an option for patients with Graves' disease and toxic nodular goitre.

Surgical Management of Substernal Thyroid Goiters

Substernal thyroid goiters can present with progressive symptoms involving compression of vital structures such as the esophagus, trachea, or large vessels. A multidisciplinary approach is critical when diagnosing and treating these patients. This article discusses patient presentation, workup, and management options for patients with substernal goiter as well as surgical pearls to minimize risk of complications.

Molecular pathology of endocrine gland tumors: genetic alterations and clinicopathologic relevance

Tumors of the endocrine glands are common. Knowledge of their molecular pathology has greatly advanced in the recent past. This review covers the main molecular alterations of tumors of the anterior pituitary, thyroid and parathyroid glands, adrenal cortex, and adrenal medulla and paraganglia. All endocrine gland tumors enjoy a robust correlation between genotype and phenotype. High-throughput molecular analysis demonstrates that endocrine gland tumors can be grouped into molecular groups that are relevant from both pathologic and clinical point of views. In this review, genetic alterations have been discussed and tabulated with respect to their molecular pathogenetic role and clinicopathologic implications, addressing the use of molecular biomarkers for the purpose of diagnosis and prognosis and predicting response to molecular therapy. Hereditary conditions that play a key role in determining predisposition to many types of endocrine tumors are also discussed.

Use of molecular testing results to analyze the overuse of atypia of undetermined significance in thyroid cytology

INTRODUCTION

The suggested atypia of undetermined significance (AUS) rate for thyroid fine-needle aspiration biopsies is 10% or less. Prompted by a high institutional AUS rate, we examined using molecular testing results (MTR) as a potential quality metric tool to reduce the AUS rate. We correlated MTR with AUS cytologic findings, surgical pathology follow-up, and individual pathologist AUS rates.

MATERIALS AND METHODS

Demographic data, cytologic diagnoses, MTR, and surgical pathology diagnoses were retrospectively obtained. MTR were classified as either positive or negative. AUS rates and MTR proportions were compared among pathologists. The cytomorphologic features of 143 AUS cases were assessed and correlated with MTR.

RESULTS

Between 2017 and 2022, 710 of 3247 thyroid fine-needle aspirations were classified as AUS, with a yearly average rate of 22% (range = 19%-26%). AUS cases included: 331 (47%) with architectural atypia; 204 (29%) with oncocytic (Hürthle cell) atypia; 99 (14%) with combined architectural and cytologic atypia; and 76 (10%) with isolated cytologic atypia. Most AUS cases with molecular testing had negative MTR (360/492, 73%). AUS with cytologic atypia had higher positive MTR risk (logarithm of odds ratio = 1.27, 95% credible interval [0.5-2.04], P = 0.001). The average positive MTR rate by pathologist was 21.5% (range 0%-35%); higher positive MTR rates had better correlation with subsequent neoplastic/malignant histologic diagnoses. The MTR sensitivity for malignant disease was 89% and the negative predictive value was 91%.

CONCLUSIONS

MTR analysis reveals the importance of cytologic atypia as a determinant of malignancy risk in AUS cases. Periodic analysis of MTR data alongside individual pathologist AUS rates can help refine diagnostic criteria and potentially reduce AUS overuse.

Hyperthyroidism: aetiology, pathogenesis, diagnosis, management, complications, and prognosis

Hyperthyroidism is a common condition with a global prevalence of 0·2-1·3%. When clinical suspicion of hyperthyroidism arises, it should be confirmed by biochemical tests (eg, low TSH, high free thyroxine [FT4], or high free tri-iodothyonine [FT3]). If hyperthyroidism is confirmed by biochemical tests, a nosological diagnosis should be done to find out which disease is causing the hyperthyroidism. Helpful tools are TSH-receptor antibodies, thyroid peroxidase antibodies, thyroid ultrasonography, and scintigraphy. Hyperthyroidism is mostly caused by Graves' hyperthyroidism (70%) or toxic nodular goitre (16%). Hyperthyroidism can also be caused by subacute granulomatous thyroiditis (3%) and drugs (9%) such as amiodarone, tyrosine kinase inhibitors, and immune checkpoint inhibitors. Disease-specific recommendations are given. Currently, Graves' hyperthyroidism is preferably treated with antithyroid drugs. However, recurrence of hyperthyroidism after a 12-18 month course of antithyroid drugs occurs in approximately 50% of patients. Being younger than 40 years, having FT4 concentrations that are 40 pmol/L or higher, having TSH-binding inhibitory immunoglobulins that are higher than 6 U/L, and having a goitre size that is equivalent to or larger than WHO grade 2 before the start of treatment with antithyroid drugs increase risk of recurrence. Long-term treatment with antithyroid drugs (ie, 5-10 years of treatment) is feasible and associated with fewer recurrences (15%) than short-term treatment (ie, 12-18 months of treatment). Toxic nodular goitre is mostly treated with radioiodine (131I) or thyroidectomy and is rarely treated with radiofrequency ablation. Destructive thyrotoxicosis is usually mild and transient, requiring steroids only in severe cases. Specific attention is given to patients with hyperthyroidism who are pregnant, have COVID-19, or have other complications (eg, atrial fibrillation, thyrotoxic periodic paralysis, and thyroid storm). Hyperthyroidism is associated with increased mortality. Prognosis might be improved by rapid and sustained control of hyperthyroidism. Innovative new treatments are expected for Graves' disease, by targeting B cells or TSH receptors.

The protective impact of hesperidin against carbimazole-induced hypothyroidism, via enhancement of inflammatory cytokines, histopathological alterations, and Nrf2/HO-1

The aim of this study was to evaluate the anti-inflammatory, antioxidant, and antiproliferative effects of hesperidin (HSP) and eltroxin (ELT) on hypothyroidism (HPO) induced by carbimazole (CBZ) in white male albino rats. Thirty-two adult rats were categorized into four groups: Group 1, no treatment (control); Group II, treated with CBZ (20 mg/kg); Group III, treated with HSP (200 mg/kg) + CBZ; and Group IV, treated with ELT (0.045 mg/kg) + CBZ. All treatments were provided as oral daily doses for 90 days. Thyroid hypofunction was significantly manifested in Group II. However, increased levels of thyroid hormones, antioxidant enzymes, nuclear factor erythroid 2-related factor 2, heme oxygenase 1, and interleukin (IL)-10, and a decrease in the level of the thyroid-stimulating hormone were observed in Groups III and IV. On the contrary, decreased levels of lipid peroxidation, inducible nitric oxide synthase, tumor necrosis factor α, IL-17, and cyclooxygenase 2 were detected in groups III and IV. The histopathological and ultrastructural findings were ameliorated in Groups III and IV; on the contrary, Group II presented with significant increases in the height and number of layers of the follicular cells. Immunohistochemistry demonstrated a marked increase in thyroglobulin and significant decreases in the levels of nuclear factor kappa B and proliferating cell nuclear antigen in Groups III and IV. These results confirmed the effectiveness of HSP as an anti-inflammatory, antioxidant, and antiproliferative agent in rats with hypothyroidism. Additional studies are required to assess its potential as a novel agent against HPO.

Clinical and ultrasonography evaluation of thyroid tumor screening in symptomatic patient of Bajulmati primary care center, Banyuwangi, East Java, Indonesia

This study aims to assess the prevalence, clinical, and ultrasonography (US) in thyroid screening in healthy subjects with general symptoms of thyroid abnormality in low iodine intake in Bajulmati primary care center, East Java Indonesia. We retrospectively reviewed US thyroid examination of 74 subjects with symptoms of mass in the neck, shaky, sleep difficulties, over sweating, and chronic fatigue on September 15th, 2021. Following the WHO guidelines, subjects also underwent physical examination in which the result were classified into 3 categories, that is, no palpable nor visible goiter, palpable but no visible goiter, as well as palpable and visible goiter. We evaluate US thyroid characteristics following Korean Society of Thyroid Radiology guidelines. Image analysis was reviewed by 4 general radiologists with 2 to 13 years' experience. Categorical variables were compared using chi-squared or Fisher exact tests. Correlation between variables was measured with gamma statistics. Statistical analyses were conducted using IBM SPSS Statistics 23.0. A P-value < .05 was considered to indicate statistical significance. Of the 74 subjects, 32 (43.2%) show abnormalities. Statistical analysis showed no significant differences in the result of thyroid US in subjects with complaint fatigue (P = .464), insomnia (P = .777), over sweating (P = .158), and tremor (P = .778), but there were significant differences with the complaint of mass in the neck (P = .008). Furthermore, there was also a strong correlation between goiter palpation and US thyroid result (R = 0.773, P = .00). We conclude there were significant differences in US result of patients with and without complaint of mass in the neck. We also found a strong correlation between goiter palpation and US examination. Clinical findings, laboratory examination, cytology and molecular markers, patients' age, nodules size, and ultrasound features should be considered for the treatment planning.

Children and adolescent patients with goiter and normal thyroid function: US findings related to underlying autoimmune thyroid diseases

This study was conducted to investigate and compare thyroid ultrasonography (US) findings in children and adolescents with goiter and normal thyroid function with positive or negative thyroid autoimmunity. From 2000 to 2020, we reviewed initial thyroid US images in 33 autoimmune thyroid diseases (AITDs) patients and 52 nonAITD patients. Our review of the images focused on thyroid parenchymal hypoechogenicity and heterogeneous echopattern subdivided into 2 groups according to severity: hypoechogenicity 1 and 2 (HO1 and HO2) and heterogeneity 1 and 2 (HE1 and HE2). HO1 and HE1 were observed more frequently in the nonAITD group (86.5% and 42.3%, respectively), while HO2 and HE2 were observed more frequently in the AITDs group (36.4% and 81.8%, respectively). More patients in the AITDs group showed change of both US groups and thyroid function state within the follow-up periods than in nonAITD group (33.3% and 5.77%, respectively). Children and adolescent AITDs patients showed more severe parenchyma hypoechogenicity and heterogeneous echopattern compared with nonAITD patients with goiter and normal thyroid function.

Iodine and Iodine Deficiency: A Comprehensive Review of a Re-Emerging Issue

Iodine is a mineral nutrient essential for the regulation of a variety of key physiological functions including metabolism and brain development and function in children and adults. As such, iodine intake and status within populations is an area of concern and research focus. This paper will review recently published studies that focus on the re-emerging issue of iodine deficiency as a global concern and declining intake among populations in developed countries. Historically, the implementation of salt-iodization programs worldwide has reduced the incidence of iodine deficiency, but 30% of the world’s population is still at risk. Iodine nutrition is a growing issue within industrialized countries including the U.S. as a result of declining iodine intake, in part due to changing dietary patterns and food manufacturing practices. Few countries mandate universal salt iodization policies, and differing agriculture and industry practices and regulations among countries have resulted in inconsistencies in supplementation practices. In the U.S., in spite of salt-iodization policies, mild-to-moderate iodine deficiency is common and appears to be increasing. European countries with the highest incidence of deficiency lack iodization programs. Monitoring the iodine status of at-risk populations and, when appropriate, public health initiatives, appear to be warranted.

Iodine deficiency is associated with increased thyroid hormone sensitivity in individuals with elevated TSH

Objective

Central sensitivity of thyroid hormone refers to the sensitivity of hypothalamic-pituitary-thyroid (HPT) axis to the change in circulating free thyroxine (fT4). A complex relationship exists between thyroxine levels and iodine nutritional status. To explore the relationship between thyroid hormone sensitivity and iodine nutritional status in elevated thyrotropin (TSH), we used national data to assess the relationship between thyroid hormone sensitivity and iodine nutritional status with contrasting demographic characteristics in China.

Methods

We enrolled 12,197 participants with TSH > 4.2 mIU/L from China. Serum and urine samples were collected, and we measured serum fT4, TSH, thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb) levels and urinary iodine concentration (UIC). The thyroid hormone sensitivity indices were calculated based on fT4 and TSH. The thyroid feedback quantile-based index (TFQI) is a new index to reflect thyroid hormone sensitivity. Higher TFQI quartiles indicated lower thyroid hormone sensitivity.

Results

The odds ratios (ORs) for the fourth versus first TFQI quartile were 0.84 (95% CI 0.72-0.99) for iodine deficiency, 1.24 (95% CI 1.05-1.47) for TPOAb+, and 0.44 (95% CI 0.40-0.50) for females. The OR of the fourth and first TFQI quartiles for age <30 years and >60 years was 2.09 (95% CI 1.82-2.41) and 1.19 (95% CI 1.05-1.36), respectively (P < 0.05). Other thyroid sensitivity indices also yielded similar results.

Conclusion

Thyroid hormone sensitivity and age have a U-shaped association in individuals with elevated TSH. Increased thyroid hormone sensitivity is associated with iodine deficiency and the female gender. Decreased thyroid hormone sensitivity is associated with TPOAb+. These findings are interesting and potentially useful for understanding the interaction between iodine nutrition and the hypothalamic-pituitary-thyroid axis.

[Epidemiology of benign thyroid disorders in the adult population of the Republic of Belarus: analysis of nationwide statistics 2009 to 2019]

BACKGROUND

Nowadays, the Republic of Belarus belongs to the countries with sufficient iodine supply, which made it possible to reduce the incidence of non-toxic goiter and congenital hypothyroidism. However, even a slight change in iodine consumption influences the pattern of thyroid diseases. In addition to iodine deficiency, other environmental conditions, as well as genetic factors, play a significant role in the etiology of thyroid diseases.

AIM

To analyze the dynamics of the main epidemiological indicators of benign thyroid diseases from 2009 to 2019 in the adult population of the Republic of Belarus, using the data of official state statistics.

MATERIALS AND METHODS

The indicators of the incidence and prevalence of benign thyroid diseases were studied on the basis of state statistics for 2009-2019. To analyze the dynamics of the studied indicators, regression analysis was used with the construction of linear and polynomial models.

RESULTS

A decrease in the incidence and prevalence of diffuse euthyroid goiter and an increase in the incidence and prevalence of nodular euthyroid goiter, thyroiditis, acquired hypothyroidism, Graves' disease, as well as the incidence of nodular toxic goiter were revealed.

CONCLUSION

Obtained data indicate, that there is an increase in the prevalence of most of the studied thyroid diseases, despite the adequate iodine supply. The above justifies the need for further study of the causes of the identified trends, as well as the necessity of developing new methods of diagnosis and treatment of thyroid diseases.

Overview of the 2022 WHO Classification of Thyroid Neoplasms

This review summarizes the changes in the 5th edition of the WHO Classification of Endocrine and Neuroendocrine Tumors that relate to the thyroid gland. The new classification has divided thyroid tumors into several new categories that allow for a clearer understanding of the cell of origin, pathologic features (cytopathology and histopathology), molecular classification, and biological behavior. Follicular cell-derived tumors constitute the majority of thyroid neoplasms. In this new classification, they are divided into benign, low-risk, and malignant neoplasms. Benign tumors include not only follicular adenoma but also variants of adenoma that are of diagnostic and clinical significance, including the ones with papillary architecture, which are often hyperfunctional and oncocytic adenomas. For the first time, there is a detailed account of the multifocal hyperplastic/neoplastic lesions that commonly occur in the clinical setting of multinodular goiter; the term thyroid follicular nodular disease (FND) achieved consensus as the best to describe this enigmatic entity. Low-risk follicular cell-derived neoplasms include non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), thyroid tumors of uncertain malignant potential, and hyalinizing trabecular tumor. Malignant follicular cell-derived neoplasms are stratified based on molecular profiles and aggressiveness. Papillary thyroid carcinomas (PTCs), with many morphological subtypes, represent the BRAF-like malignancies, whereas invasive encapsulated follicular variant PTC and follicular thyroid carcinoma represent the RAS-like malignancies. This new classification requires detailed subtyping of papillary microcarcinomas similar to their counterparts that exceed 1.0 cm and recommends not designating them as a subtype of PTC. The criteria of the tall cell subtype of PTC have been revisited. Cribriform-morular thyroid carcinoma is no longer classified as a subtype of PTC. The term "Hürthle cell" is discouraged, since it is a misnomer. Oncocytic carcinoma is discussed as a distinct entity with the clear recognition that it refers to oncocytic follicular cell-derived neoplasms (composed of > 75% oncocytic cells) that lack characteristic nuclear features of PTC (those would be oncocytic PTCs) and high-grade features (necrosis and ≥ 5 mitoses per 2 mm²). High-grade follicular cell-derived malignancies now include both the traditional poorly differentiated carcinoma as well as high-grade differentiated thyroid carcinomas, since both are characterized by increased mitotic activity and tumor necrosis without anaplastic histology and clinically behave in a similar manner. Anaplastic thyroid carcinoma remains the most undifferentiated form; squamous cell carcinoma of the thyroid is now considered as a subtype of anaplastic carcinoma. Medullary thyroid carcinomas derived from thyroid C cells retain their distinct section, and there is a separate section for mixed tumors composed of both C cells and any follicular cell-derived malignancy. A grading system for medullary thyroid carcinomas is also introduced based on mitotic count, tumor necrosis, and Ki67 labeling index. A number of unusual neoplasms that occur in the thyroid have been placed into new sections based on their cytogenesis. Mucoepidermoid carcinoma and secretory carcinoma of the salivary gland type are now included in one section classified as "salivary gland-type carcinomas of the thyroid." Thymomas, thymic carcinomas and spindle epithelial tumor with thymus-like elements are classified as "thymic tumors within the thyroid." There remain several tumors whose cell lineage is unclear, and they are listed as such; these include sclerosing mucoepidermoid carcinoma with eosinophilia and cribriform-morular thyroid carcinoma. Another important addition is thyroblastoma, an unusual embryonal tumor associated with DICER1 mutations. As in all the WHO books in the 5th edition, mesenchymal and stromal tumors, hematolymphoid neoplasms, germ cell tumors, and metastatic malignancies are discussed separately. The current classification also emphasizes the value of biomarkers that may aid diagnosis and provide prognostic information.

An Investigation on the Risk Factors of Thyroid Diseases in Community Population in Hainan

BACKGROUND

In recent years, the incidence of thyroid diseases has increased significantly, which has seriously affected people's work and life. The purpose of this study was to explore the epidemiological characteristics of thyroid diseases and autoantibodies.

METHOD

According to the principle of overall sampling, resident residents ≥18 years and who will not move within 5 years are randomly selected. A total of 2136 eligible individuals were divided into case and control groups according to whether they have thyroid disease. Finally, the impact of potential risk factors on thyroid diseases was evaluated.

RESULTS

The overall prevalence of thyroid disease was 58.3%, and there was a significant difference in the prevalence of thyroid disease between women and men (p = 0.004). Except for the age group ≥70 years, with the increase in age, the prevalence gradually increased (p < 0.05). Participants with positive thyroid autoantibodies (TPOAb or TgAb) had a higher prevalence than participants with negative autoantibodies. The positive rate of autoantibodies in women was higher than that in men (p < 0.05). UIC (p = 0.004) and free thyroid hormone (FT4) (p = 0.001) levels of men were higher than those of women, and the TSH level of women was higher than that of men (p = 0.002). The regression analysis showed that women, older age, and family history of thyroid disease were independent risk factors for thyroid disease.

CONCLUSION

The prevalence of thyroid diseases in Hainan was high. Women are more susceptible to thyroid disease than men, and the prevalence increased with age.

Proteomic profiling of thyroid tissue in patients with obesity and benign diffuse goiter

Goiter is a term to describe the enlargement of the thyroid gland. The pathophysiology and molecular changes behind development of diffuse benign goiter remains unclear. The present study targeted to identify and describe the alterations in the thyroid tissue proteome from patients (obese euthyroid) with benign diffuse goiter (BDG) using proteomics approach. Thyroid tissue samples, from 7 age and sex matched, patients with BDG and 7 controls were obtained at the time of surgery. An untargeted proteomic analysis of the thyroid tissue was performed out utilizing two-dimensional difference (2D-DIGE) in gel electrophoresis followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for identification of the proteins. Progenesis software was used to identify changes in expression of tissue proteins and found statistically significant differences in abundance in a total of 90 proteins, 46 up and 44 down (1.5-fold change, ANOVA, p ≤ 0.05) in BDG compared to the control group. Bioinformatic analysis using Ingenuity Pathway Analysis (IPA) identified dysregulation of signalling pathways linked to ERK1/2, Glutathione peroxidase and NADPH oxidase associated to organismal injury and abnormalities, endocrine system disorders and cancer. The thyroid tissue proteome in patients with BDG revealed a significant decrease in thyroglobulin along with dysregulation of glycolysis and an increase in prooxidant peroxidase enzymes. Dysregulation of metabolic pathways related to glycolysis, redox proteins, and the proteins associated with maintaining the cytoskeletal structure of the thyrocytes was also identified.

Iodoprophylaxis and thyroid autoimmunity: an update

Adequate iodine intake is necessary for normal thyroid function. Iodine deficiency is associated with serious complications, but also iodine excess can lead to thyroid dysfunction, and iodine supplementation aimed to prevent iodine deficiency disorders has been associated with development of thyroid autoimmunity. The epidemiology of thyroid diseases has undergone profound changes since the implementation of iodoprophylaxis, notably by means of iodine-enriched salt, specifically resulting in decreased prevalence of goiter and neonatal hypothyroidism, improved cognitive function development in infancy, and reduced incidence of more aggressive forms of thyroid cancer. The main question we address with this review is the clinical relevance of the possible effect on autoimmunity exerted by the use of iodine-enriched salt to correct iodine deficiency. In animal models, exogenous iodine is able to trigger or exacerbate thyroid autoimmunity, but it is still not clear whether the observed immunological changes are due to a direct effect of iodine on immune response, or whether they represent a secondary response to a toxic effect of iodine on thyroid tissue. Previous iodine status of a population seems to influence the functional thyroid response to increased iodine intake and possibly the development of thyroid autoimmunity. Moreover, the prevalence of thyroid antibodies, regarded as hallmark of autoimmune thyroid disease, varies between populations under the influence of genetic and environmental factors, and the presence of thyroid antibodies does not always coincide with the presence of thyroid disease or its future development. In addition, the incidence of autoimmune diseases shows a general increasing trend in the last decades. For all these reasons, available data are quite heterogeneous and difficult to analyze and compare. In conclusion, available data from long-term population surveys show that a higher than adequate population iodine intake due to a poorly controlled program of iodine prophylaxis could induce thyroid dysfunction, including thyroid autoimmunity mostly represented by euthyroid or subclinical hypothyroid autoimmune thyroiditis. Close monitoring iodine prophylaxis is therefore advised to ensure that effects of both iodine deficiency and iodine excess are avoided.

Association between Urinary Iodine Concentration and Thyroid Nodules in Adults: A Cross-Sectional Study in China

Background

Associations between iodine intake and thyroid nodules (TNs) were not consistent. We aimed to illustrate the relationship between urinary iodine concentration (UIC) and TNs.

Methods

A total of 12,698 participants were enrolled in analysis. All of the participants filled out questionnaires and underwent physical examinations, laboratory tests, and thyroid ultrasonography. UIC, serum thyrotropin (TSH), thyroid peroxidase antibodies (TPOAb), and thyroglobulin antibodies (TgAb) were measured in the central laboratory.

Results

The prevalence of TNs was 16.00%, and the median UIC was 206.1 μg/L. TNs and UIC were negatively related when UIC was less than 527 μg/L (adjusted OR = 0.87; 95% CI, 0.80, 0.94), and the relationship between UIC and TNs was not statistically significant when UIC was greater than 527 μg/L (adjusted OR = 1.25; 95% CI, 0.98, 1.60). In women, UIC was negatively associated with risk for TNs (adjusted OR 0.95; 95% CI, 0.91, 0.99).

Conclusion

The relationship between TNs and UIC differed between men and women. The risk of TNs decreased with the elevation of UIC in men when UIC was lower than 527 μg/L, while UIC and the presence of TNs were negatively correlated in women. In the future, cohort studies or other studies that can explain causality must be conducted to explore the relationship between iodine status and TNs.

Prevalence of Pathogenic Germline DICER1 Variants in Young Individuals Thyroidectomised Due to Goitre - A National Danish Cohort

INTRODUCTION

DICER1 syndrome encompasses a variety of benign and malignant manifestations including multinodular goitre, which is the most common manifestation among individuals carrying pathogenic DICER1 variants. This is the first study estimating the prevalence of pathogenic DICER1 variants in young individuals with multinodular goitre.

METHODS

Danish individuals diagnosed with nodular goitre based on thyroidectomy samples in 2001-2016 with the age limit at time of operation being ≤ 25 years were offered germline DICER1 gene testing.

RESULTS

Six of 46 individuals, 13% (CI [3.3;22.7], p <0.05), diagnosed with nodular goitre on the basis of thyroidectomy samples under the age of 25 years had pathogenic germline variants in DICER1. They were found in different pathoanatomical nodular goitre cohorts i.e. nodular goitre (n=2), colloid nodular goitre (n=3) and hyperplastic nodular goitre (n=1).

CONCLUSIONS

We recommend referral of patients thyroidectomised due to goitre aged <21 years and patients thyroidectomised due to goitre aged <25 years with a family history of goitre to genetic counselling. Patients of all ages thyroidectomised due to goitre, who are affected by another DICER1 manifestation should be referred to genetic counselling.

A matrix-assisted laser desorption/ionization imaging mass spectrometric approach to study weight-related changes within thyroid tissue

Obesity is associated with numerous comorbidities along with abnormalities of the endocrine system, more commonly manifesting as dysfunctions of the thyroid gland such as goiter. Changes in weight, especially an increase, could lead to an increase in the incidence of thyroid dysfunction; however, its pathophysiology remains to be elucidated. In the present study, we aimed to interrogate the changes in the protein distribution and abundance between the lean patients and patients with obesity thyroid tissue sections through utilizing this technique. The FFPE-fixed thyroid tissue blocks from the selected cases and controls were identified and targeted for matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) analysis. Patients in the 30 to 75 years age group and undergoing total thyroidectomy for benign thyroid disease were recruited. Patients with thyroid cancers, autoimmune disorders, and other inflammatory conditions were excluded from the study. The selected patients were divided into two groups according to their BMIs: lean (BMI < 25) and obese (BMI > 35). An initial trial set was used as a pilot study for the optimization of the MALDI IMS protocol that was next applied to the selected thyroid tissues. MALDI IMS data from all the samples were aligned and statistical analysis carried out by k-means and linear discriminant analysis (LDA) classification model using principle component analysis (PCA) results were evaluated between the two groups: controls (lean) and cases (obese). Receiver operator characteristic (ROC) curves were alternatively used to calculate the variability of the identified peptides. The discriminating peptides were also independently identified and related to their corresponding proteins by using liquid chromatography and tandem mass spectrometry (LC-MS/MS) analyses. Eight peptides mainly from thyroglobulin were found to be upregulated whereas 10 others were found to be downregulated in the lean compared to the obese group. Through this technique, we will be able to better understand the relationship between the disease entity and obesity.

On the possibility of using temperature to aid in thyroid nodule investigation

Thyroid nodules are common, and their investigation is very important to exclude the possibility of cancer. The increase in blood vessels of malignant tumours may be related to local temperature augmentation detectable on the skin surface. The objective of this paper is to evaluate the feasibility of Infrared Thermography for cancer identification. For this purpose, two studies were performed. One used numerical modelling to simulate regional metabolic temperature propagation to evaluate whether a nodule is perceptible on the skin surface. A second study considered thyroid nodule identification by using convolutional neural networks (CNNs). First, variations in nodular size and fat thickness were investigated, showing that the fat layer has an important role in regional heat transfer. In the second study, the training process achieved accuracy of 96% for in-sample and 95% for validation. In the testing phase, 92% accuracy, 100% precision and 80% recall were achieved. Thus, the presented studies suggest the feasibility of using Infrared Thermography with the CNN Artificial Intelligence technique as additional information in the investigation of thyroid nodules for patients without a very thick subcutaneous fat layer.

HYPOTHYROIDISM AND GOITER IN A YOUNG MALE WITH SUSPECTED DIETARY IODINE DEFICIENCY FOLLOWED BY THYROTOXICOSIS AFTER IODINE SUPPLEMENTATION

Objective

Iodine deficiency disorders (IDDs) remain a major public health concern in most parts of the world but are extremely rare in North America. We describe a case of goiter in a young male with dietary history and findings suggestive of IDD.

Methods

Laboratory and imaging procedures including thyroid function tests, autoantibodies, urine iodine, thyroid ultrasound, and radioactive iodine (RAI) uptake scan were performed.

Results

On initial presentation, thyroid-stimulating hormone (TSH) was 24.4 mIU/L (normal range is 0.4 to 5.0 mIU/L), free thyroxine was <0.4 ng/dL (normal range is 0.8 to 1.8 ng/dL), and thyroid peroxidase antibody was positive at 43 IU/mL (normal range is <35 IU/mL). He reported consuming strawberries and peanut butter sandwiches with no intake of dairy or seafood due to gastrointestinal issues (abdominal pain, bloating, and nausea). Physical exam revealed a diffusely enlarged, palpable thyroid gland (grade II goiter). Ultrasound of the neck showed an enlarged thyroid gland with no nodules. RAI uptake scan showed diffuse increased uptake (91%). Given his poor diet, a 24-hour urinary iodine excretion test was ordered which was suggestive of very low iodine intake. He was started on multivitamins with 150 μg of iodine daily. On follow up, clinical exam showed grade I goiter and TSH had normalized to 0.7 mIU/L and free thyroxine was 1.2 ng/dL. He continued on iodine supplementation and tolerated iodine-rich foods. Six months later, thyroid function tests showed hyperthyroidism with TSH of <0.002 ng/dL and free thyroxine was elevated to 2.8 ng/dL. Iodine supplements were stopped.

Conclusion

Hypothyroidism and goiter due to IDD should be suspected in the setting of poor dietary intake. IDDs can be rapidly diagnosed in a patient on a restricted diet with multiple urinary iodine determinations and RAI study. Regular thyroid labs should be done to monitor for hyperthyroidism that can develop after iodine supplementation.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate thyroidectomy.

BACKGROUND

Surgical management of thyroid disease has evolved considerably over several decades leading to variability in rendered care. Over 100,000 thyroid operations are performed annually in the US.

METHODS

The medical literature from 1/1/1985 to 11/9/2018 was reviewed by a panel of 19 experts in thyroid disorders representing multiple disciplines. The authors used the best available evidence to construct surgical management recommendations. Levels of evidence were determined using the American College of Physicians grading system, and management recommendations were discussed to consensus. Members of the American Association of Endocrine Surgeons reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines analyze the indications for thyroidectomy as well as its definitions, technique, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Fine Needle Aspiration Biopsy Diagnosis, Molecular Testing, Indications, Extent and Outcomes of Surgery, Preoperative Care, Initial Thyroidectomy, Perioperative Tissue Diagnosis, Nodal Dissection, Concurrent Parathyroidectomy, Hyperthyroid Conditions, Goiter, Adjuncts and Approaches to Thyroidectomy, Laryngology, Familial Thyroid Cancer, Postoperative Care and Complications, Cancer Management, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal surgical management of thyroid disease.

Constitutive TSH receptor activation as a hallmark of thyroid autonomy

Since its cloning more than 30 years ago, the thyrotropin receptor (TSHR) has emerged as a pivotal player in thyroid physiology and pathophysiology. In particular, hyperthyroidism due to autoimmune disease or thyroid autonomy is linked with TSHR activation via autoantibodies or mutations respectively. This review summarises clinical aspects of constitutive TSH receptor activation by naturally occurring somatic or germline TSHR mutations resulting in TSH-independent thyroid function and cell proliferation.

Radiofrequency Ablation on Autonomously Functioning Thyroid Nodules: A Critical Appraisal and Review of the Literature

Background: Thyroid nodules are an extremely common occurrence, as their prevalence in the general population is estimated to range between 50 and 70%. Some of these nodules are autonomously functioning such that they can cause hyperthyroidism over time. In this case, surgery and radioiodine represent the standard of care. Nevertheless, patients might have contraindications or be unwilling to undergo these treatments. Minimally-invasive ultrasound-guided techniques, such as laser and radiofrequency ablation (RFA), have been recently introduced into clinical practice as an alternative treatment for symptomatic benign thyroid nodules. Due to their efficacy and tolerability, these techniques have become increasingly available and their usage has been extended also to autonomously functioning thyroid nodules (AFTN). Methods: In this narrative review, we will describe the studies reporting the therapeutic effects of RFA on AFTN, the studies reporting how RFA compares to the other treatment modalities, as well as the current indications for the use of RFA in patients with AFTN. For this purpose, a comprehensive literature search was independently conducted by three investigators on PubMed, EMBASE, and the Cochrane Library from inception up to February 2020 to identify published articles concerning the effects of RFA on AFTN. Results and Conclusions: Current consensus statements and guidelines support the notion that RFA should be regarded as a first-line therapy for non-functioning benign thyroid nodules, while it remains a valid second-line option for AFTN treatment in case of contraindications or patient unwillingness to undergo surgery or radioiodine.

The Effect of Iodine Status on the Risk of Thyroid Nodules: A Cross-Sectional Study in Zhejiang, China

OBJECTIVE

The aim of this study was to explore whether iodine nutrition is associated with the risk of thyroid nodules among adult population in Zhejiang Province, China.

METHODS

A cross-sectional study was conducted in the general population aged 18 years or older. A total of 2,710 subjects received physical examination, questionnaires, and thyroid ultrasonography. Urinary iodine concentration (UIC) and thyroid hormone levels were measured and documented for each subject. 4 multiple logistic regression models adjusted for other risk factors were applied to analyze the association between iodine nutrition and thyroid nodules.

RESULTS

The prevalence of thyroid nodules was 15.5% among all adults. As indicated by all 4 models, subjects with UIC varying from 200 μg l^-1 to 399 μg l^-1 had lower risk of thyroid nodules compared with those with relatively low UIC (<100 μg l^-1), with approximately 37-57 percent reduction in risk. Moreover, subjects with UIC between 100 and 199 μg l^-1 had a decreased risk of thyroid nodules in model 1 and 2 (OR = 0.75, 95% CI, 0.58-0.97; OR = 0.75, 95% CI, 0.58-0.97, respectively). However, there was no significant difference of risk in thyroid nodules between subjects with high UIC (≥400 μg l^-1) and low UIC (<100 μg l^-1). Furthermore, intake of iodized salt was inversely associated with risk of thyroid nodules, with approximately 69-77 percent reduction in risk.

CONCLUSION

The relationship between UIC and the risk of thyroid nodules is U-shaped. Consumption of noniodized salt is an independent risk factor of thyroid nodules.

Changes in subtypes of overt thyrotoxicosis and hypothyroidism following iodine fortification

OBJECTIVE

To investigate the impact of mandatory iodine fortification (IF) on the incidence of nosological subtypes of overt thyrotoxicosis and hypothyroidism.

DESIGN

We identified and scrutinized all possible new cases of overt thyrotoxicosis and hypothyroidism in an open cohort in Northern Jutland (n = 309 434; 1 January 1997) during the years 2014-2016. Individual medical history was evaluated to verify and detail the incidence of overt thyroid dysfunction and for classification into nosological subtypes. A number of cases were excluded during final verification due to spontaneous normalization of thyroid function, as they had no medical history suggesting a known condition, which could transiently affect thyroid function (subacute/silent thyroiditis, PPTD and iatrogenic thyroid dysfunction). An identical survey was conducted in 1997-2000 prior to mandatory IF of salt (13 µg/g) that was in effect from year 2001.

RESULTS

The standardized incidence rate (SIR) of verified overt thyrotoxicosis decreased markedly from 97.5/100 000/year in 1997-2000 to 48.8 in 2014-2016 (SIRR: 0.50 [95% CI: 0.45-0.56]). This was due to a distinct decrease in the SIR of multinodular toxic goitre (SIRR: 0.18 [0.15-0.23]), solitary toxic adenoma (SIRR: 0.26 [0.16-0.43]) and to a lesser degree Graves' disease (SIRR: 0.67 [0.56-0.79]). SIR for overt hypothyroidism was unaltered by 2014-2016 (SIRR: 1.03 [0.87-1.22]). However, age distribution shifted with more young and fewer elderly cases of verified overt hypothyroidism.

CONCLUSION

Mandatory IF caused a substantial reduction in SIR of verified overt thyrotoxicosis (especially of nodular origin) while avoiding an increase in SIR of verified overt hypothyroidism.

Thyrotoxicosis with concomitant thyroid cancer

Thyrotoxicosis with concomitant thyroid cancer is rare and poorly recognized, which may result in delayed diagnosis, inappropriate treatment and even poor prognosis. To provide a comprehensive guidance for clinicians, the etiology, pathogenesis, diagnosis and treatment of this challenging setting were systematically reviewed. According to literatures available, the etiologies of thyrotoxicosis with concomitant thyroid cancer were categorized into Graves' disease with concurrent differentiated thyroid cancer (DTC) or medullary thyroid cancer, Marine-Lenhart Syndrome with coexisting DTC, Plummer's disease with concomitant DTC, amiodarone-induced thyrotoxicosis with concomitant DTC, central hyperthyroidism with coexisting DTC, hyperfunctioning metastases of DTC and others. The underlying causal mechanisms linking thyrotoxicosis and thyroid cancer were elucidated. Medical history, biochemical assessments, radioiodine uptake, anatomic and metabolic imaging and ultrasonography-guided fine-needle aspiration combined with pathological examinations were found to be critical for precise diagnosis. Surgery remains a mainstay in both tumor elimination and control of thyrotoxicosis, while anti-thyroid drugs, beta-blockers, 131I, glucocorticoids, plasmapheresis, somatostatin analogs, dopamine agonists, radiation therapy, chemotherapy and tyrosine kinase inhibitors should also be appropriately utilized as needed.

Thyroid nodule recurrence following lobo-isthmectomy: incidence, patient's characteristics, and risk factors

PURPOSE

This study was aimed at assessing the incidence and timing of thyroid nodules recurrence, defined as appearance of new benign or malignant nodules in contralateral lobe in patients with benign thyroid nodules or thyroid microcarcinoma treated with lobo-isthmectomy. Patient's characteristics and risk factors associated with this phenomenon were also investigated.

METHODS

A retrospective study was performed by evaluating 413 patients undergoing lobo-isthmectomy with a minimum follow-up of 1 year. Clinical characteristics, surgical interventions and complications, histological diagnosis, and thyroid function at last follow-up were collected.

RESULTS

Single or multiple thyroid nodule recurrence equally occurred in 80 patients (23%) with a median time to relapse of ~ 5 years (range 0.3-34.5 years) after lobo-isthmectomy. Recurrence was significantly associated with younger age (< 46 years) and number of pregnancies in women. Development of hypothyroidism was not rare either (~ 10%) and appeared in 3-19 months; a preoperative TSH level > 2.43 mIU/L was associated with the need of l-thyroxin replacement therapy after surgery. The most frequent surgical complication was transient hypoparathyroidism (4.6%), while the rate of permanent hypoparathyroidism significantly increased in patients submitted to completion thyroidectomy (5.3%).

CONCLUSIONS

Thyroid nodules recurrence following lobo-isthmectomy is not a rare event and occurs within 5 years after surgery, more frequently in younger patients with family history of nodular goiter and in women with multiple pregnancies. Pre-surgical TSH levels may predict the development of post-surgical hypothyroidism, possibly improving the management of patients addressed to surgery.

Investigation on the factors that influence the prevalence of thyroid nodules in adults in Tianjin, China

Studies have shown that prevalence of thyroid nodules (TNs) has been increasing recently. However, the factors that may influence TN prevalence is not fully understood. In this study, we aimed to understand the prevalence of TNs and identify possible factors that are associated with the prevalence of TNs in Tianjin, China. Subjects aged 18 years or older were randomly collected and all subjects received thyroid ultrasonography, physical examination and questionnaires. Subjects (n = 2647) were divided into the case group in which the subjects had TNs and the control group in which the subjects did not have TNs. Potential influencing factors on TNs including sex, age, iodine status, thyroid volume, thyroid hormone (TSH), thyroid autoantibody TPOAb, TGAb and living habits were analyzed. Our results showed that the overall TN prevalence was 26.7%. The prevalence of TNs in women was higher than that in men (P < 0.05). TN prevalence increased with age (P < 0.001), and a U-shaped curve relationship between urine iodine concentrations (UICs) and prevalence of TNs was observed. The positive rate of TPOAb and goiter rate in case group was higher than that in control group (P < 0.05). The thyroid volume in case group was larger than that in control group (P < 0.001). Other factors that may influence TNs included high blood pressure, iodized salt, menopause, seafood intake, and education levels. None of UIC, TSH, TPOAb and TGAb were associated with TN prevalence in regression models. In conclusion, our results showed that TNs prevalence in Tianjin was high. TNs prevalence was higher in women than in men, and it increases with age. The older, female, high education level physical labor and goiter are independent risk factors for TNs.

Effects of isoflavones on breast tissue and the thyroid hormone system in humans: a comprehensive safety evaluation

Isoflavones are secondary plant constituents of certain foods and feeds such as soy, linseeds, and red clover. Furthermore, isoflavone-containing preparations are marketed as food supplements and so-called dietary food for special medical purposes to alleviate health complaints of peri- and postmenopausal women. Based on the bioactivity of isoflavones, especially their hormonal properties, there is an ongoing discussion regarding their potential adverse effects on human health. This review evaluates and summarises the evidence from interventional and observational studies addressing potential unintended effects of isoflavones on the female breast in healthy women as well as in breast cancer patients and on the thyroid hormone system. In addition, evidence from animal and in vitro studies considered relevant in this context was taken into account along with their strengths and limitations. Key factors influencing the biological effects of isoflavones, e.g., bioavailability, plasma and tissue concentrations, metabolism, temporality (pre- vs. postmenopausal women), and duration of isoflavone exposure, were also addressed. Final conclusions on the safety of isoflavones are guided by the aim of precautionary consumer protection.

[Genetics of thyroid nodules and thyroid carcinoma]

Thyroid nodules are heterogeneous tumors with variable genetic signatures. Thyroid cancers are monoclonal lesions with a defined histomorphology that largely depends on the underlying somatic mutation. While the mutation rate is generally low in differentiated thyroid cancers, poorly differentiated and anaplastic thyroid cancers show a high mutation load. The identification of somatic mutations in fine needle aspirates can be helpful for the differential diagnostics of thyroid nodules; however, a prognostic contribution is less certain. The molecular pathology of thyroid tumors is helpful for the development of targeted therapies and may infer novel immuno-oncological concepts for advanced aggressive thyroid cancers.

Association of Pro-apoptotic Bad Gene Expression Changes with Benign Thyroid Nodules

BACKGROUND/AIM

This study aimed to investigate the role of the mitochondrial apoptotic pathway in benign thyroid nodules.

MATERIALS AND METHODS

Paired samples of nodular and normal tissues were collected from 26 patients with nodular goiters undergoing thyroidectomy. Variable expression of Bcl-2, Bax and Bad genes were evaluated by quantitative PCR.

RESULTS

Expression level of Bad gene in nodules was found to be significantly decreased compared to normal tissues (p=0.049). A positive correlation was observed between nodule size and Bad expression levels (correlation coefficient=0.563, p=0.004); and this correlation was stronger in hot nodules (n=18, correlation coefficient=0.689, p=0.003). No significant difference was observed between nodular and normal tissue expressions of Bax and Bcl-2.

CONCLUSION

These results suggest that Bad expression correlates with the size of benign thyroid nodules and also its relatively lower expression in nodules, warrant further investigation.

Changes of Nicotinamide Phosphoribosyltransferase Expressions in Thyroid Glands of Patients with Different Thyroid Pathologies

Purpose

Our aim was to analyze NAMPT expression in thyroid tissue derived from patients with Graves' disease with (GD) and without (GO) orbitopathy, patients with toxic nodular goiters (TNG) and thyroid cancers (TC), and healthy controls.

Methods

153 thyroid tissue samples of consecutive patients who underwent thyroidectomy were collected. Previous therapy with steroids was an exclusion criterion. We collected clinicopathological data of all subjects and we assessed NAMPT expression using qPCR.

Results

We found the highest NAMPT expression in the thyroids of patients with GO (n = 20) and cancers (n = 40). Also, there was statistically significant NAMPT overexpression in patients with TNG (n = 30). Relatively low NAMPT expression was found in GD patients (n = 21) and in the control group (n = 39). In one-way ANCOVA, we confirmed that NAMPT expression differs between subgroups and that it is not influenced by age, BMI, or sex of patients.

Conclusions

Reported alteration of NAMPT expression might suggest its involvement in thyroid pathologies. Observed NAMPT overexpression in patients with GO and its relatively low levels in thyroids of patients with GD without eye changes do not confirm causal relationship between NAMPT level and orbitopathy, but this needs further investigation.

Clinical Significance of Thyroid-Stimulating Hormone Receptor Gene Mutations and/or Sodium-Iodine Symporter Gene Overexpression in Indeterminate Thyroid Fine Needle Biopsies

Objectives: To examine the prevalence of genetic alterations of thyroid-stimulating hormone receptor (TSHR) gene and sodium-iodine symporter (NIS) in a series of thyroid fine needle biopsy (FNB) specimens with indeterminate cytology, and to assess the correlation of the type of genetic changes with clinical features and follow-up results in the target thyroid nodule. Methods: Between February 2015 and September 2017, 388 consecutive FNBs with indeterminate cytology were evaluated for TSHR mutations and NIS gene overexpression using ThyroSeqV.2 next-generation sequencing (NGS) panel. Medical records were reviewed for target nodules. Results: Among 388 indeterminate FNBs, TSHR mutations and/or NIS overexpression were detected in 25 (6.4%) nodules. Ten nodules (2.6%) harbored TSHR mutations only, 7 nodules (1.8%) over-expressed NIS gene only, and 8 nodules (2.1%) had both alterations. The TSHR mutations were located between codons 281 and 640, with codon 453 being the most frequently affected. The allelic frequency of the mutated TSHR ranged from 6 to 36%. One nodule with NIS overexpression was simultaneously detected EIF1AX mutation and GNAS mutation. Nodules with TSHR mutations and/or NIS overexpression presented hyperfunctioning (n = 4), hypofunctioning (n = 5), and isofunctioning (n = 3) on the available thyroid scintigraphies. Eight cases accompanied with hyperthyroidism in which only 1 was caused by the target nodule. Evidence of co-existing autoimmune thyroid disease (AITD) and multinodular goiter were found in 52% and 52% of cases, respectively. Seven nodules underwent surgeries and all were benign on final pathology. None of 9 nodules with follow-up by ultrasound (3~33 mon, median 12 mon) showed grow in size. Conclusions: TSHR mutations and/or NIS overexpression can be detected in pre-operative FNB specimens using the NGS approach. These genetic alterations occurred in 6.4% thyroid nodules in this consecutive series with indeterminate cytology. They present not only in hyperfunctioning nodules but also in hypo- or iso-functional nodules, indicating their prevalence may be higher than previously expected. Co-existing AITD was common in cases with these molecular alterations. None of our patients with TSHR mutations and/or NIS overexpression manifested malignant outcomes. How to use these two molecular markers in thyroid FNBs to guide our clinical practice warrants further investigation.

Molecular pathology of thyroid tumours of follicular cells: a review of genetic alterations and their clinicopathological relevance

Thyroid cancer is the most common endocrine malignancy. Knowledge of the molecular pathology of thyroid tumours originating from follicular cells has greatly advanced in the past several years. Common molecular alterations, such as BRAF p.V600E, RAS point mutations, and fusion oncogenes (RET-PTC being the prototypical example), have been, respectively, associated with conventional papillary carcinoma, follicular-patterned tumours (follicular adenoma, follicular carcinoma, and the follicular variant of papillary carcinoma/non-invasive follicular thyroid neoplasm with papillary-like nuclear features), and with papillary carcinomas from young patients and arising after exposure to ionising radiation, respectively. The remarkable correlation between genotype and phenotype shows how specific, mutually exclusive molecular changes can promote tumour development and initiate a multistep tumorigenic process that is characterised by aberrant activation of mitogen-activated protein kinase and phosphoinositide 3-kinase-PTEN-AKT signalling. Molecular alterations are becoming useful biomarkers for diagnosis and risk stratification, and as potential treatment targets for aggressive forms of thyroid carcinoma. What follows is a review of the principal genetic alterations of thyroid tumours originating from follicular cells and of their clinicopathological relevance.

Temporal Changes in Thyroid Nodule Volume: Lack of Effect on Paranodular Thyroid Tissue Volume

BACKGROUND

The term "nodular goiter" has long been used to refer to a nodular thyroid gland, based on the assumption that nodule growth may be associated with hyperplasia of the surrounding non-nodular tissue. The aim of this prospective, multicenter, observational study was to determine whether nodule growth is accompanied by growth in the non-nodular tissue.

METHODS

Eight Italian thyroid-disease referral centers enrolled 992 consecutive patients with one to four benign nodules. Nodular and non-nodular thyroid tissue volumes were assessed for five years with annual ultrasound examinations.

RESULTS

In participants whose nodules remained stable (n = 839), thyroid volumes did not change (baseline 15.0 mL [confidence interval (CI) 14.5-15.6]; five-year evaluation 15.1 mL [CI 14.5-15.7]). In participants with significant growth of one or more nodule (n = 153), thyroid volumes increased and by year 5 were significantly greater than those of the former group (17.4 mL [CI 16-18.7]). In 76 individuals with unilateral nodules that grew, the mean nodular lobe volume significantly exceeded that of the contralateral lobe (8.6 mL [CI 7.4-9.8] vs. 6.7 mL [CI 6-7.4]). The unaffected lobe volumes remained stable over time, while nodular lobes grew steadily and were significantly greater at the end of follow-up (10.1 mL [CI 8.9-11.3]). Excluding the volume of the largest growing nodule in these cases, the remaining volume of the affected lobe remained virtually unchanged with respect to its baseline value. Furthermore, there was no significant difference in the non-nodular tissue volume between the unaffected lobe and the affected lobe (with the largest growing nodule volume subtracted), both at baseline and at the end of follow-up.

CONCLUSIONS

The growth of thyroid nodules is a local process, not associated with growth of the surrounding non-nodular tissue. Therefore, a normal-sized thyroid containing nodules should be referred to as a "uni- or multinodular thyroid gland" and considered a distinct entity from "uni- or multinodular goiter."

The compensatory enlargement of the remaining thyroid lobe following hemithyroidectomy is small and without impact on symptom relief

According to previous studies, hemithyroidectomy results in growth of the remaining thyroid lobe by up to 30% in first 12 months after surgery. However, this estimate is based on imprecise methods, high inter- and intra-observer variability, and lack of blinding of the measurements. Furthermore, it is unknown whether enlargement of the remaining hemi-thyroid interferes with the improvement in symptoms after surgery for goiter. We aimed to assess the impact of postoperative thyroid growth on goiter symptom relief following hemithyroidectomy in patients with benign nodular goiter. Outcomes were measured before and 6 months after hemithyroidectomy in 44 patients. Thyroid volumes were determined by two independent and blinded observers using magnetic resonance imaging (MRI). Inter- and intra-observer variability was visualized by Bland-Altman plots. Goiter symptoms were assessed by the Thyroid-Specific Patient-Reported-Outcome Questionnaire (ThyPRO) on a scale from 0 to 100 points. After hemithyroidectomy, the remaining thyroid lobe was 13.7 ± 6.4 mL, and enlarged by a mean of 1.8 mL over 6 months [95% confidence interval (CI) (1.6; 2.1), p < 0.001], corresponding to an increase of 17% [95% CI (12; 22)]. The Goiter Symptom score improved by 27 points [95% CI (21; 34), p < 0.0001] from median 39 points (range 2-86) at baseline, and was unaffected by the compensatory thyroid growth. Six months after hemithyroidectomy, using blinded MRI evaluations, we demonstrated a small but significant postoperative growth of the remaining hemi-thyroid, which did not significantly affect the considerable improvement in goiter symptoms.

[Molecular Pathogenesis of Thyroid Nodules: Relevance for Clinical Care]

Thyroid nodules represent heterogeneous tumors with distinct molecular signatures. While benign thyroid nodules correspond to poly- or monoclonal tumors, thyroid carcinomas are monoclonal and thus "real" neoplasms. These are caused by somatic mutations that lead to the constitutive activation of specific signaling cascades and determine the corresponding histology and also partly the functional phenotype of the thyroid tumor. Dedifferentiation of thyroid carcinomas is accompanied by the occurrence of additional mutations in the tumors. The mutation load of thyroid carcinomas correlates with their biological behavior. In clinical practice, detection of somatic mutations can help in the cytological differential diagnosis. In the prognostic assessment of thyroid tumors, proof of classical oncogene mutations (BRAF, RAS) has little relevance. Other genetic alterations, especially TERT promoter mutations that occur with increasing frequency in advanced thyroid carcinomas, probably have a prognostic significance. The molecular signature, however, is of great relevance for the development and application of targeted therapies in advanced carcinomas (radioactive iodine-refractory DTC, PDTC and ATC, metastatic medullary carcinoma). For this, there is increasing evidence from clinical studies and case reports that underline the concept of "oncogene addiction" as a pathogenetically relevant mechanism of thyroid tumorigenesis and carcinogenesis.

The Relationship of TPOAb and TGAb with Risk of Thyroid Nodules: A Large Epidemiological Study

Objective: The association between thyroid hormones, thyroid autoantibodies, and thyroid nodules are still not clear. The cross-sectional study, conducted in Hangzhou, China in 2010, aimed to identify the relationship of thyroid hormones and autoantibodies with thyroid nodules. Methods: Information regarding social demography was collected by a questionnaire. Thyroid hormones (triiodothyronine, thyroxin, free triiodothyronine, free thyroxin, thyrotropin), thyroid autoantibodies (thyroid peroxidase antibody, antithyroglobulin antibody), and thyroid nodules (diagnosed by ultrasonography) was measured in 1271 adults. The association of thyroid hormones and thyroid autoantibodies with thyroid nodules was evaluated using multiple logistic regression models. Results: The prevalence of thyroid nodules among males and females was 29.49% and 33.15%, respectively. The thyroid hormone level in the thyroid nodules group was significantly higher than the non-nodules group (all p values < 0.05), except reversely in TSH (thyroid stimulating hormone) (p = 0.0532) and TGAb (thyroglobulin antibody) (p = 0.0004). High levels of TPOAb (thyroid peroxidase antibody) (OR (Odds Ratio) = 1.51, 95% CI (confidence interval): 0.99–2.30) and TGAb (OR = 2.86, 95% CI: 1.49–5.51) were associated with increased risk of thyroid nodules, compared with corresponding low levels. However, following sub-analyses in two genders, the similar associations were only observed in females (TPOAb: OR = 1.63, 95% CI: 0.99–2.68; TGAb: OR = 3.13, 95% CI: 1.53–6.40). Conclusions: The present study indicated that thyroid autoantibodies were positively associated with the risk of thyroid nodules in Chinese coastal adults.

Resveratrol has anti-thyroid effects both in vitro and in vivo

Resveratrol is a natural polyphenol with antioxidant, anti-inflammatory, and antiproliferative properties. We have shown previously that resveratrol decreases sodium/iodide symporter expression and iodide uptake in thyrocytes, both in vitro and in vivo. In the present study, we further investigated the effects of resveratrol, with evaluation of the expression of additional thyroid-specific genes in the FRTL-5 rat thyroid cell line: thyroglobulin, thyroid peroxidase, TSH receptor, Nkx2-1, Foxe1 and Pax8. We observed decreased expression of these genes in FRTL-5 cells treated with 10 μM resveratrol. The effects of resveratrol was further evaluated in vivo using Sprague-Dawley rats treated with resveratrol 25 mg/kg body weight intraperitoneally, for 60 days. No clinical signs of hypothyroidism were seen, although the treated rats showed significant increase in thyroid size. Serum TSH and thyroid hormone levels were in the normal range, with significantly higher TSH seen in resveratrol-treated rats, compared with control rats. Histological and immunohistochemical analyses confirmed increased proliferative activity in the thyroid from resveratrol-treated rats. These data suggest that resveratrol acts as a thyroid disruptor and a goitrogen, which indicates the need for caution as a supplement and for therapeutic uses.

Breed, Coat Color, and Hair Length as Risk Factors for Hyperthyroidism in Cats

Background

Hyperthyroidism is very common in older cats, but the etiopathogenesis is poorly understood. Decreased risk of hyperthyroidism has been reported in certain colorpoint breeds, and this observation previously has been hypothesized to result from relatively greater tyrosine availability for thyroid hormone production because of limited ability to convert tyrosine to melanin pigment. However, studies investigating a potential link between coat pigmentation and risk of hyperthyroidism are limited.

Objective

To identify associations between coat phenotype and hyperthyroidism by investigation of breed, coat color, and hair length as risk factors for the disease.

Animals

Data were used from 4,705 cats aged ≥10 years, referred to a single veterinary teaching hospital (2006–2014) in the United Kingdom.

Methods

Retrospective, epidemiological, cross‐sectional study using Bayesian multivariable logistic regression to assess risk factors for hyperthyroidism.

Results

Burmese (odds ratio [OR], 0.01; 0.00–0.23; P = .004), Tonkinese (OR, 0.05; 0.00–0.95; P = .046), Persian (OR, 0.21; 0.10–0.44; P < .001), Siamese (OR, 0.27; 0.12–0.61; P = .002), Abyssinian (OR, 0.04; 0.00–0.74; P = .031), and British shorthair (OR, 0.47; 0.28–0.79; P = .004) breeds had decreased risk of hyperthyroidism compared to domestic shorthairs. Longhaired, nonpurebred cats (OR, 1.30; 1.03–1.64; P = .028) were at increased risk of hyperthyroidism. Coat color/pattern was not associated with hyperthyroidism in nonpurebred cats.

Conclusions and Clinical Importance

We identified decreased risk of hyperthyroidism in the Tonkinese, Abyssinian, and British shorthair breeds, identified an association between risk of hyperthyroidism and hair length, and confirmed decreased risk in Burmese, Siamese, and Persian breeds. Additional studies are warranted to further investigate these findings.

The genetic landscape of benign thyroid nodules revealed by whole exome and transcriptome sequencing

The genomic alterations for benign thyroid nodule, especially adenomatoid nodule, one of the most common types of hyperplasia lesion, are ill-studied. Here, we show whole-exome sequencing and/or transcriptome sequencing data on adenomatoid nodules with or without coincidental papillary thyroid carcinoma (PTC). Somatic mutation of BRAF (22/32) is only detected in PTC, while mutations in SPOP (4/38), ZNF148 (6/38) and EZH1 (3/38) are found enriched in adenomatoid nodule. In an expanded cohort of adenomatoid nodule (n=259) mutually exclusive SPOPP94R, EZH1Q571R and ZNF148 mutations are identified in 24.3% of them. Adenomatoid nodules show very few overlapped mutations and distinct gene expression patterns with their coincidental PTC. Phylogenetic tree analysis uncovers that PTCs evolved independently from their matched benign nodules. Our findings reveal that benign nodules possess a unique molecular signature that differs from PTC and provide genomic evidence for the conventional belief that PTC and benign nodules have independent origin.

Primary Care Endocrinology in the Adult Woman

Diabetes mellitus, thyroid disorders, and osteoporosis are endocrine conditions affecting a significant proportion of women presenting to the obstetrician-gynecologist. Obstetrician-gynecologists are often the first health-care providers that young women see in adulthood, and thus, have a critical opportunity to identify women at risk for gestational and overt diabetes and manage the condition in those who have developed it. The obstetrician-gynecologist should be aware of the appropriate therapeutic options and treatment goals (eg, hemoglobin A1c) for women with diabetes. Thyroid disorders often present with menstrual irregularities or infertility, can affect pregnancy outcomes, and contribute to cardiovascular and bone disorders as women age. Finally, osteoporosis and low bone mineral density affect a substantial proportion of older women and some younger women with risk factors for secondary osteoporosis. The morbidity and mortality of osteoporotic fractures is substantial. There are many lifestyle interventions and therapeutic options available for these conditions, and the gynecologist plays a key role in optimizing risk factor assessment, screening, and providing treatment when appropriate.

Inheritable and sporadic non-autoimmune hyperthyroidism

Hyperthyroidism is a clinical state that results from high thyroid hormone levels which has multiple etiologies, manifestations, and potential therapies. Excluding the autoimmune Graves disease, autonomic adenomas account for the most import cause of non-autoimmune hyperthyroidism. Activating germline mutations of the TSH receptor are rare etiologies for hyperthyroidism. They can be inherited in an autosomal dominant manner (familial or hereditary, FNAH), or may occur sporadically as a de novo condition, also called: persistent sporadic congenital non-autoimmune hyperthyroidism (PSNAH). These three conditions: autonomic adenoma, FNAH and PSNAH constitute the inheritable and sporadic non-autoimmune hyperthyroidism. Particularities in epidemiology, etiology, molecular and clinical aspects of these three entities will be discussed in this review in order to guide to an accurate diagnosis allowing among others genetic counseling and presymptomatic diagnosis for the affected families. The optimal treatment based on the right diagnosis will avoid consequences of a persistent or relapsing hyperthyroidism.

Deep Sequencing Reveals Spatially Distributed Distinct Hot Spot Mutations in DICER1-Related Multinodular Goiter

CONTEXT

Nontoxic multinodular goiter (MNG) occurs frequently, but its genetic etiology is not well established. Familial MNG and MNG occurring with ovarian Sertoli-Leydig cell tumor are associated with germline DICER1 mutations. We recently identified second somatic DICER1 ribonuclease (RNase) IIIb mutations in two MNGs.

OBJECTIVE

The objective of the study was to investigate the occurrence of somatic DICER1 mutations and mutational clonality in MNG.

PATIENTS

MNGs from 15 patients (10 with and five without germline DICER1 mutations) were selected based on tissue availability.

DESIGN

Core biopsies/scrapings (n = 70) were obtained, sampling areas of follicular hyperplasia, hyperplasia within colloid pools, unremarkable thyroid parenchyma, and areas of thyroid parenchyma, not classified. After capture with a Fluidigm access array, the coding sequence of DICER1 was deep sequenced using DNA from each core/scraping.

RESULTS

All germline DICER1-mutated cases were found to harbor at least one RNase III mutation. Specifically, we identified 12 individually distinct DICER1 RNase IIIb hot spot mutations in 32 of the follicular hyperplasia or hyperplasia within colloid pools cores/scrapings. These mutations are predicted to affect the metal-ion binding residues at positions p.Glu1705, p.Asp1709, p.Gly1809, p.Asp1810, and p.Glu1813. Somatic RNase IIIb mutations were identified in the 10 DICER1 germline mutated MNGs as follows: two cases contained one somatic mutation, five cases contained two mutations, and three cases contained three distinct somatic hot spot mutations. No RNase IIIb mutations were identified in the MNGs from individuals without germline DICER1 mutations.

CONCLUSIONS

This study demonstrates that nodules within MNG occurring in DICER1 syndrome are associated with spatially distributed somatic DICER1 RNase IIIb mutations.