Preclinical assessment of a mathematical model for ablation zone prediction in thyroid laser ablation.

To develop and validate a 3D simulation model to calculate laser ablation (LA) zone size and estimate the volume of treated tissue for thyroid applications, a model was developed, taking into account dynamic optical and thermal properties of tissue change. For validation, ten Yorkshire swines were equally divided into two cohorts and underwent thyroid LA at 3 W/1,400 J and 3 W/1,800 J respectively with a 1064-nm multi-source laser (Echolaser X4 with Orblaze™ technology; ElEn SpA, Calenzano, Italy). The dataset was analyzed employing key statistical measures such as mean and standard deviation (SD). Model simulation data were compared with animal gross histology. Experimental data for longitudinal length, width (transverse length), ablation volume and sphericity were 11.0 mm, 10.0 mm, 0.6 mL and 0.91, respectively at 1,400 J and 14.6 mm, 12.4 mm, 1.12 mL and 0.83, respectively at 1,800 J. Gross histology data showed excellent reproducibility of the ablation zone among same laser settings; for both 1,400 J and 1,800 J, the SD of the in vivo parameters was ≤ 0.7 mm, except for width at 1,800 J, for which the SD was 1.1 mm. Simulated data for longitudinal length, width, ablation volume and sphericity were 11.6 mm, 10.0 mm, 0.62 mL and 0.88, respectively at 1,400 J and 14.2 mm, 12.0 mm, 1.06 mL and 0.84, respectively at 1,800 J. Experimental data for ablation volume, sphericity coefficient, and longitudinal and transverse lengths of thermal damaged area showed good agreement with the simulation data. Simulation datasets were successfully incorporated into proprietary planning software (Echolaser Smart Interface, Elesta SpA, Calenzano, Italy) to provide guidance for LA of papillary thyroid microcarcinomas. Our mathematical model showed good predictability of coagulative necrosis when compared with data from in vivo animal experiments.

Stevens-Johnson syndrome/toxic epidermal necrolysis associated with natural thyroid medication.

Steven-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) is a rare immunologic hypersensitivity reaction to stimuli that presents as widespread eruption with mucocutaneous detachment and involvement of other organs. Multiple causes have been noted in literature, including numerous medications. In this report, we present a 52-year-old woman who arrived at the emergency department with a complaint of rash, malaise, and pruritus. She subsequently developed diffuse cutaneous and mucosal detachment. Work-up supported a diagnosis of SJS/TEN secondary to her thyroid replacement therapy, derived from desiccated pig thyroid glands. The patient's natural thyroid medication was discontinued and she responded well to appropriate treatment. This case is unique in that thyroid replacement therapy is not a commonly reported trigger of SJS/TEN. Providers should be aware of the potential for natural thyroid and other animal-derived natural medications to cause adverse reactions such as SJS/TEN.

Diagnostic Efficiency of ACR-TIRADS Score for Differentiating Benign and Malignant Thyroid Nodules of Various Pathological Types.

BACKGROUND Thyroid nodule prevalence reaches 65% in the general population. Hence, appropriate ultrasonic examination is key in disease monitoring and management. We investigated the American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS) score for diagnosis of benign and malignant thyroid nodules and pathological types. MATERIAL AND METHODS A retrospective study was conducted. According to ultrasound images, ultrasonic characteristics of benign and malignant thyroid nodules and different pathological types were analyzed using ACR-TIRADS score, and diagnostic value was determined. AUCs were compared for tumor diagnosis and differentiation. RESULTS Overall, 1675 thyroid nodules from 1614 patients were included. AUC value of papillary thyroid carcinoma (PTC) diagnosed with ACR-TIRADS was highest (0.955 [95% CI=0.946-0.965]), while that of follicular thyroid carcinoma (FTC) was lowest (0.877 [95% CI=0.843-0.912]). FTC had the highest sensitivity (95.1%) and lowest specificity (64.8%). When the cut-off value was 5.5 points, accuracy of diagnosing PTC and anaplastic thyroid carcinoma (ATC) was highest, 80.5% and 78.7% respectively. Comparison of the multi-index prediction model constructed by multivariable logistic regression analysis and prediction model constructed by ACR-TIRADS score showed, when evaluating PTC and ATC, the multi-index model was better: AUCs of PTC were 0.966 vs 0.955, and AUCs of ATC were 0.982 vs 0.952, respectively, (P<0.05). CONCLUSIONS ACR-TIRADS score-based ultrasound examination of thyroid nodules aids diagnosis of benign and malignant thyroid nodules. TIRADS criteria favor diagnosis of PTC (and ATC) over FTC. ACR-TIRADS score can help clinicians diagnose thyroid nodules quickly and earlier, exhibits good clinical value, and can prevent missed diagnoses.

Autoimmunity, New Potential Biomarkers and the Thyroid Gland-The Perspective of Hashimoto's Thyroiditis and Its Treatment.

Autoimmune thyroid disease (AITD) is the most common organic specific illness of the thyroid gland. It may manifest as the overproduction or the decline of thyroxine and triiodothyronine. Hyperthyroidism develops due to the overproduction of hormones as an answer to the presence of stimulatory antibodies against the TSH receptor. Hashimoto's thyroiditis (HT) is generally characterized by the presence of thyroid peroxidase and thyroglobulin antibodies, with a concomitant infiltration of lymphocytes in the thyroid. Due to the progressive destruction of cells, AITD can lead to subclinical or overt hypothyroidism. Pathophysiology of AITD is extremely complicated and still not fully understood, with genetic, environmental and epigenetic factors involved in its development. Due to increasing incidence and social awareness of this pathology, there is an urgent need to expand the background concerning AITD. A growing body of evidence suggests possible ways of treatment apart from traditional approaches. Simultaneously, the role of potential new biomarkers in the diagnosis and monitoring of AITD has been highlighted recently, too. Therefore, we decided to review therapeutic trends in the course of AITD based on its pathophysiological mechanisms, mainly focusing on HT. Another aim was to summarize the state of knowledge regarding the role of new biomarkers in this condition.

Machine learning to predict the occurrence of thyroid nodules: towards a quantitative approach for judicious utilization of thyroid ultrasonography.

Introduction: Ultrasound is instrumental in the early detection of thyroid nodules, which is crucial for appropriate management and favorable outcomes. However, there is a lack of clinical guidelines for the judicious use of thyroid ultrasonography in routine screening. Machine learning (ML) has been increasingly used on big data to predict clinical outcomes. This study aims to leverage the ML approach in assessing the risk of thyroid nodules based on common clinical features. Methods: Data were sourced from a Chinese cohort undergoing routine physical examinations including thyroid ultrasonography between 2013 and 2023. Models were established to predict the 3-year risk of thyroid nodules based on patients' baseline characteristics and laboratory tests. Four ML algorithms, including logistic regression, random forest, extreme gradient boosting, and light gradient boosting machine, were trained and tested using fivefold cross-validation. The importance of each feature was measured by the permutation score. A nomogram was established to facilitate risk assessment in the clinical settings. Results: The final dataset comprised 4,386 eligible subjects. Thyroid nodules were detected in 54.8% (n=2,404) individuals within the 3-year observation period. All ML models significantly outperformed the baseline regression model, successfully predicting the occurrence of thyroid nodules in approximately two-thirds of individuals. Age, high-density lipoprotein, fasting blood glucose and creatinine levels exhibited the highest impact on the outcome in these models. The nomogram showed consistency and validity, providing greater net benefits for clinical decision-making than other strategies. Conclusion: This study demonstrates the viability of an ML-based approach in predicting the occurrence of thyroid nodules. The findings highlight the potential of ML models in identifying high-risk individuals for personalized screening, thereby guiding the judicious use of ultrasound in this context.

Clinical biomarkers for thyroid immune-related adverse events in patients with stage III and IV gastrointestinal tumors.

Background: Thyroid immune-related adverse events (irAEs) associated with immune checkpoint inhibitor (ICI) treatment appear to correlate with a better prognosis. We aimed to investigate clinical biomarkers associated with thyroid irAEs. Methods: We retrospectively analyzed data from 129 patients receiving programmed cell death protein 1 (PD-1) inhibitors for stage III and IV gastrointestinal tumors. Patients were divided into two groups: "thyroid irAEs" group and "no thyroid irAEs" group. We compared continuous variables using Mann-Whitney U and Kruskal-Wallis tests and categorical variables using Pearson's chi-square test. Survival curves were generated using the Kaplan-Meier method, and associations between clinical features and thyroid irAEs were assessed using univariate and multivariate logistic regression models. Associations for thyroid irAEs and outcomes [progression-free survival (PFS), overall survival (OS)] of the patients were performed with a Cox proportional hazard model. Results: A total of 129 patients, including 66 gastric cancer, 30 esophageal squamous cell carcinoma, and 33 hepatocellular carcinoma (HCC), were involved in this analysis with 47 cases of thyroid irAEs occurrence. The Cox proportional hazard model analysis confirmed the extended PFS [hazard rate (HR) = 0.447, 95% confidence interval (CI): 0.215 to 0.931, p = 0.031] and OS (HR = 0.424, 95% CI: 0.201 to 0.893, p = 0.024) for thyroid irAEs group when compared with those of the no thyroid irAEs group. Association between thyroid irAEs and clinical characteristics at baseline was analyzed subsequently by univariate analysis. Higher body mass index (p = 0.005), increased eosinophil count (p = 0.014), increased lactate dehydrogenase (p = 0.008), higher baseline thyroid stimulating hormone (TSH) (p = 0.001), HCC (p = 0.001) and increased adenosine deaminase (ADA) (p = 0.001) were linked with thyroid irAEs occurrence. The multivariable logistic regression model indicated that ADA [odds rate (OR) = 4.756, 95% CI: 1.147 to 19.729, p = 0.032] was independently associated with thyroid irAEs occurrence. Conclusions: Increased baseline level of ADA was associated with thyroid irAEs occurrence in patients with advanced gastrointestinal tumors who received ICI treatment. In the case of abnormal ADA, attention should be paid to the risk of thyroid irAEs.

Do PFCAs drive the establishment of thyroid cancer microenvironment? Effects of C6O4, PFOA and PFHxA exposure in two models of human thyroid cells in primary culture.

BACKGROUND: Exposure to environmental pollutants is suspected to be one of the potential causes accounting for the increase in thyroid cancer (TC) incidence worldwide. Among the ubiquitous pollutants, per-polyfluoroalkyl substances (PFASs), were demonstrated to exert thyroid disrupting effects. Perfluoroalkyl carboxylates (PFCAs) represent a subgroup of PFAS and include perfluoro carboxylic acids (PFOA and PFHxA) and perfluoropolyether carboxylic acid (C6O4). The potential relationship between exposure to PFCAs and TC was not yet fully elucidated. This in vitro study investigated whether certain PFCAs (C6O4, PFOA, and PFHxA) can influence the composition of TC microenvironment. METHODS: Two models of normal thyroid cells in primary cultures: Adherent (A-NHT) and Spheroids (S-NHT) were employed. A-NHT and S-NHT were exposed to C6O4, PFOA or PFHxA (0; 0.01; 0.1, 1; 10; 100; 1000 ng/mL) to assess viability (WST-1 and AV/PI assay), evaluate spherification index (SI) and volume specifically in S-NHT. CXCL8 and CCL2 (mRNA and protein), and EMT-related genes were assessed in both models after exposure to PFCAs. RESULTS: PFHxA reduced the viability of both A-NHT and S-NHT. None of the PFCAs interfered with the volume or spherification process in S-NHT. CXCL8 and CCL2 mRNA and protein levels were differently up-regulated by each PFCAs, being PFOA and PFHxA the stronger inducers. Moreover, among the tested PFCAs, PFHxA induced a more consistent increase in the mRNA levels of EMT-related genes. CONCLUSIONS: This is the first evaluation of the effects of exposure to PFCAs on factors potentially involved in establishing the TC microenvironment. PFHxA modulated the TC microenvironment at three levels: cell viability, pro-tumorigenic chemokines, and EMT-genes. The results provide further evidence of the pro-tumorigenic effect of PFOA. On the other hand, a marginal effect was observed for C6O4 on pro-tumorigenic chemokines.

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.

Difficulties in investigating and treating fibrosing thyroid disorder (overlap of fibrosing variant of Hashimoto's thyroiditis and Riedel's thyroiditis).

A gentleman in his 90s presented with a slowly enlarging goitre over 18 months, causing manifestations of superior vena cava obstruction, dysphagia and hoarseness of voice. Investigations were suggestive of a fibrosing thyroid pathology. Surgical management was avoided due to high surgical risk. Treatment included prednisolone and tamoxifen with palliative management in the event of further medical deterioration. This article illustrates the difficulties in diagnosing and managing fibrosing thyroid diseases.

Feasibility and safety of modified en-bloc resection in endoscopic thyroid surgery via bilateral areolar approach - long-term institutional analysis ten years after surgery.

Purpose: This study aimed to introduce a new modified en-bloc resection method and evaluate its feasibility and safety in endoscopic thyroid surgery via bilateral areolar approach (BAA). Methods: Papillary thyroid carcinoma (PTC) patients who underwent lobectomy and ipsilateral central node dissection (CND) via the BAA approach were retrospectively reviewed. Their clinical characteristics and outcomes were evaluated, including operative duration, lymph node yield (LNY), surgical complications, recurrence rate, and metastasis rate, over a ten-year follow-up period. Simultaneous lobectomy and CND were performed in the modified en-bloc group, whereas lobectomy was performed first, followed by CND in the conventional group. Results: The study included 108 patients in the modified en-bloc group and 213 in the conventional group. There were no significant differences in gender, age, tumor locations, tumor dominant nodule size, or the incidence of concomitant Hashimoto thyroiditis when comparing clinicopathologic characteristics. The comparison of operative duration (P = 0.14), blood loss (P = 0.13), postoperative hospital stay (P = 0.58), incidence of transient vocal cord paralysis (P = 0.90) and hypocalcemia (P = 0.60) did not show any differences. The mean LNY achieved in the central compartment of the modified en-bloc group (7.5 ± 4.5) was significantly higher than that in the conventional group (5.6 ± 3.6). Two patients in the modified en-bloc group and two in the conventional group experienced metastasis after surgery during the ten-year follow-up (1.8% vs. 0.9%, P = 0.60). The learning curve analysis showed a significant decrease in operative duration after the 25-35th cases for modified en-bloc resection. Conclusions: The modified en-bloc resection method in endoscopic thyroid surgery via BAA is a technically feasible and safe procedure with excellent cosmetic outcomes for selective PTC patients.

Changes in thyroid cytology reporting in the 3rd edition of the Bethesda system.

Reporting fine-needle aspiration of thyroid nodules in the Bethesda classification is a practice widely used internationally and by us. The revised third edition of the Bethesda System of Reporting Thyroid Cytopathology brings changes in terminology, content, and new chapters. In terms of terminology, an obvious change is the removal of the two-word names of three categories while maintaining the six diagnostic categories of the previous versions - new: BI - non-diag- nostic, BIII - atypia of undetermined significance, BIV - follicular neoplasia. In the detailed description of the findings within the individual categories, the ter- minological changes adopted by the fifth edition of the WHO classification of thyroid neoplasia are respected - in particular, the recommended name follicular thyroid nodular disease for the most frequently represented category BII - benign. In the evaluation itself, the diagnostic specifications accepted by the current WHO classification of histopathological findings are reflected in the individual categories - if they are applicable at the cytological level. Targeted attention will need to be paid to high grade features. The revised version brings new chapters dedicated to molecular testing and evaluation of the paediatric population.

Thyroid US-guided FNA techniques: A prospective,randomized controlled study.

BACKGROUND: Thyroid nodules are common in the general population. Ultrasonography is the most efficient diagnostic approach to evaluate thyroid nodules. The US FNAC procedure can be performed using either the short axis (perpendicular), or a long axis (parallel) approach to visualize the needle as it is advanced toward the desired nodule. The main aim of this study was to compare the percentage of non-diagnostic results between the long and short axis approach. METHODS: A prospective study that included a randomized controlled trial and was divided into two arms-the short axis and the long axis-was conducted. A total of 245 thyroid nodules were collected through the fine needle aspiration cytology, performed with ultrasound, from march 2021 to march 2022. The patient's demographic information were collected and also nodules characteristics. RESULTS: Of 245 nodules sampled, 122 were sampled with the long axis method, while 123 with the short axis method. There is not significantly less non diagnostic approach with either method compared to the other (11.5 % vs 16.3 % respectively). DISCUSSION: Previous studies came to the conclusion that the long axis method yields fewer non diagnostic samples. This study evaluated the two FNA approaches which were proceeded by the same physician who is expert in both techniques. CONCLUSION: The US FNAC performed in the long axis approach will not produce more conclusive results and less non diagnostic results (Bethesda category 1) than the short axis approach one.

A vocal cord palsy caused by the uterine cancer metastatic tumor in the mediastinum revealed in a patient with a thyroid lesion: a case report and review of the literature.

BACKGROUND: The main cause of vocal cord palsy (VCP) is idiopathic impairment of the recurrent laryngeal nerve (RLN). However, solid tumors along the pathway of the RLN can also impact the nerve's function. We presented a patient with a thyroid lesion and VCP due to a bulky metastatic mass (uterine cancer) on the aortic arch field in the mediastinum. The report aims to show the significance of comorbid tumors in thyroid pathology and the importance of additional diagnostic methods in avoiding unnecessary surgeries. A patient's lifetime and the outcome of the disease were also presented. CASE PRESENTATION: A 58-year-old Ukrainian woman with a hoarse voice, intermittent dry cough, and weakness was presented to an endocrine surgeon. Thyroid pathology included signs of hypothyroidism treated with Thyroxine 112.5 µg and a nodule in the left lobe. The lesion is located on the posterior aspect of the lobe, which could probably be a cause of RLN involvement. Fine needle aspiration biopsy (FNAB) was performed twice with Bethesda category 2 result. Fibrolaryngoscopy (FLS) revealed the median position of the left vocal cord. Idiopathic, laryngeal, and thyroid causes of the VCP were excluded. Additionally, the patient displayed her anamnesis of the endometrial clear cell carcinoma following hysterectomy, external beam radiation therapy, and chemotherapy. The mediastinal metastasis was revealed sixteen years later. A chest computed tomography (CT) with intravenous contrast was done. A bulky tumor was found right under the aortic arch. Subsequently, the voice complaints reduced significantly after 4 chemotherapy courses. Cancer progression had led to the appearance of lymph node metastases on the supraclavicular region. Following six months the 60-year-old patient had passed away. CONCLUSION: A history of the disease should always be kept in mind when assessing a patient's complaints. VCP in case of thyroid pathology and previous secondary malignancy may be caused by metastatic tumor anywhere along the RLN pathway. Such a rare case shows the importance of additional methods of examination which may avoid unnecessary thyroid surgeries.

Correlation between extraocular muscle enlargement and thyroid autoantibodies in thyroid eye disease.

PURPOSE: This study aimed to investigate the factors affecting extraocular muscle enlargement in thyroid eye disease (TED). STUDY DESIGN: Retrospective study. METHODS: The thyroid-stimulating hormone (TSH) receptor antibody (TRAb), thyroid-stimulating antibody (TSAb), antithyroid peroxidase antibody (ATPO), and antithyroglobulin antibody (ATG) levels in patients diagnosed with TED who underwent orbital magnetic resonance imaging were assessed. The control group comprised the contralateral eye of patients who underwent orbital magnetic resonance imaging (MRI) for unilateral eyelid tumors or orbital disease. The thickness of the bilateral rectus muscles and superior oblique muscles was measured on orbital MRI. Muscle enlargement was classified as unilateral/bilateral and symmetric/asymmetric. The effects of age, sex, smoking history, TSH, thyroid hormone, and thyroid autoantibodies on the muscle thickness and number of enlarged muscles were assessed by use of simple and multiple regression analyses. RESULTS: The TED and control groups comprised 41 and 44 cases, respectively. The positivity rate of TSAb in patients with TED was 92.7% higher than that of the other autoantibodies. Muscle enlargement was observed in 29 of the 41 cases (70.7%). Older age and higher TSAb levels were identified as significant factors affecting the total muscle thickness and number of enlarged muscles. Bilateral muscle enlargement and asymmetrical muscle enlargement were observed in 17 (58.6%) and 23 (79.3%) of the 29 cases, respectively. The TSAb levels and age had no significant effect on the type of muscle enlargement. CONCLUSIONS: TSAb showed significant associations with extraocular muscle enlargement. Measurement of TSAb, rather than of TRAb, may be more useful for diagnosing extraocular muscle enlargement in patients with TED.

Comparison of Cytological Adequacy between 23- and 25-Gauge in Ultrasound-Guided Fine-Needle Aspiration of Thyroid Nodules: A Single-Center Prospective Study.

INTRODUCTION: Approximately 15% of fine-needle aspiration (FNA) of thyroid nodules are considered nondiagnostic. Several factors are potentially involved, including clinical and nodule features but also the gauge (G) of the needle used. However, few studies have compared the cytological adequacy obtained with different gauge needles and the data are controversial. We aimed to evaluate cytological adequacy results using 23- or 25-G needles. METHODS: This study is an observational and prospective study of thyroid nodules submitted to ultrasound-guided FNA. The procedure was performed randomly using 23- or 25-G needles. The samples were reported by different cytopathologists who were blinded to the information of the gauge of the needle used. Statistical analysis was performed to compare cytological adequacy of FNA between the two groups. RESULTS: A total of 177 thyroid nodules were included - 98 (55.4%) using 23-G and 79 (44.6%) using 25-G needles. The 23-G group presented a higher rate of cytological adequacy (69.4% [68/98] vs. 46.8% [37/79], p = 0.002). No differences were found between the two groups regarding patient or nodule characteristics. On logistic regression, 23-G needles correlated with better cytological adequacy (unadjusted OR 2.57 [95% CI: 1.39-4.77]), even after adjusting for nodule dimension, location, and type of cytology (slides +/- additional liquid-based cytology) (adjusted OR 2.44 [95% CI: 1.23-4.84]). CONCLUSION: The gauge of the needle used was found to be an independent predictor of cytological adequacy, with 23-G needles providing more adequate samples. Further investigation is needed to confirm our results in order to stablish the optimal diagnosis technique.

The Danish investigation on iodine intake and thyroid disease (DanThyr): history and implications.

Due to mild-to-moderate iodine deficiency in Denmark, health authorities initiated a voluntary iodine fortification (IF) program in 1998, which became mandatory in 2000. In line with recommendations from the World Health Organization, the Danish investigation on iodine intake and thyroid disease (DanThyr) was established to monitor the effect on thyroid health and disease. The program involved different study designs and followed two Danish sub-populations in the years before IF and up till 20 years after. Results showed that the IF was successfully implemented and increased the level of iodine intake from mild-moderate iodine deficiency to low adequacy. The level of thyroglobulin and thyroid volume decreased following IF, and there was an indication of fewer thyroid nodules. The incidence of hyperthyroidism increased transiently following IF but subsequently decreased below the pre-fortification level. Conversely, thyroid-stimulating hormone levels and the prevalence of thyroid autoimmunity increased along with an increase in the incidence of hypothyroidism. These trends were mirrored in the trends in treatments for thyroid disease. Most differences in thyroid health and disease between regions with different iodine intake levels before IF attenuated. This review illustrates the importance of a monitoring program to detect both beneficial and adverse effects and exemplifies how a monitoring program can be conducted when a nationwide health promotion program - as IF - is initiated.

Multi-UniFocality (MUF), in contrast to multifocality, in thyroid lesions: Relation to lymphocytic thyroiditis.

Whereas multifocality typically concerns papillary thyroid carcinoma (PTC) without specification of intrathyroidal metastatic or independent nature of tumor foci, the designation of the latter as Multi-UniFocal (MUF) may be relevant for select cases. A case series involving multifocal thyroid lesions with divergent histopathological morphology and/or molecular profile, with molecular evaluation of multiple individual tumor foci per patient based on a next-generation sequencing approach, was retrospectively reviewed. Twenty-five patient cases with multifocal thyroid lesions suggestive of MUF, with 2-6 (median 3) tumor foci per patient, were described. Tumor lesions comprised diverse histopathology, including PTC, (E)FVPTC, NIFTP, FA, FTC, and oncocytic. Morphologically similar and/or diverse tumor foci harbored different molecular alterations (suggestive of non-shared clonality); with(out) coexistent similar foci harboring identical molecular alterations; or (partly) shared molecular alterations. MUF was associated with chronic lymphocytic thyroiditis in almost half of the cases. The recognition of MUF may justify the independent clinical consideration per individual tumor focus; as separate lesions albeit within a multifocal context. The potential clinical relevance and prognostic value of MUF remain to be further established.

Impact of methimazole-induced hypothyroidism on postnatal swine.

Thyroid hormones regulate metabolic rate, nutrient utilization, growth, and development. Swine are susceptible to thyroid suppression in response to disease or environmental conditions, but the physiological impact of such disruption has not been established. The objective of this study was to evaluate the impact of hypothyroidism induced with the antithyroid medication methimazole (MMI). 10 mg/kg MMI significantly decreased circulating triiodothyronine (T3) for the duration of treatment but had only a transient effect on circulating thyroxine (T4). Thyroid tissue weight was significantly increased by more than 3.5-fold in response to MMI treatment. Histologically, the eosinophilic colloid was largely absent from the thyroid follicle which displayed a disorganized columnar epithelium consistent with goiter. MMI induced hypothyroidism has no effect on growth rate over 28 days. Hepatic expression of genes associated with thyroid metabolism (DIO1, DIO2, and DIO3), lipid utilization (CD36, FASN, and ACACA), apoptosis (TP53, PERP, SIVA1, and SFN) and proliferation (CDK1, CDK2, CDK4, and CDKN1A) were unaffected by treatment. Collectively these results demonstrate that MMI induces mild systemic hypothyroidism and pronounced goiter, indicating a strong homeostatic central regulation within the hypothalamic pituitary thyroid axis. This combined with limited peripheral effects, indicates resilience to hypothyroidism in modern swine.