The Heinous Hobnail: A Case Report of the Rare Hobnail Variant of Papillary Thyroid Carcinoma.

The hobnail variant of papillary thyroid carcinoma (HVPTC) represents a distinctive and relatively rare histological subtype of thyroid malignancies. This variant is characterized by its unique cellular morphology with a hobnail appearance, that is, cells with apically positioned nuclei. There are other characteristics like micropapillary pattern and loss of cohesiveness of cells, which are indicative of HVPTC. It can be difficult to distinguish this pattern from other thyroid neoplasms; thus, a thorough microscopical examination is required. Thyroglobulin, thyroid transcription factor-1 (TTF-1), and other thyroid markers are commonly expressed by the tumor cells. Clinically, HVPTC is similar to conventional papillary thyroid cancer (PTC) in many aspects like incidence and epidemiology, but the former is associated with a worse prognosis. According to some research, the hobnail variety might behave more aggressively than conventional PTC, which highlights how crucial it is to identify and comprehend this distinct subtype. While the genetic and molecular underpinnings of HVPTC are still being elucidated, some studies have reported associations with specific genetic alterations, including BRAF, TP53, and TERT mutations. Investigating these molecular signatures may contribute to a better understanding of the variant's pathogenesis and potentially guide targeted therapeutic approaches in the future. In order to customize treatment plans, histopathology is essential in correctly diagnosing it. In this article, we present a case of PTC which presented as a solitary nodule on ultrasonogram in a 40-year-old female.

Multifocal Extramedullary Plasmacytoma of the Thyroid With Cervical and Paratracheal Lymph Node Involvement and Progression to Multiple Myeloma.

Extramedullary plasmacytomas without evidence of systemic illness make up less than 5% of all plasma cell neoplasms. The incidence of extramedullary plasmacytoma of the thyroid region is exceedingly rare. This report discusses the case of a 72-year-old male with extramedullary plasmacytoma of the thyroid. The patient underwent a total thyroidectomy for an enlarging right-sided thyroid nodule, and intraoperatively, the plasmacytoma was found to have an extracapsular component with adherence to the regional soft tissue as well as involvement of the right laryngeal nerve and regional lymph nodes. Despite a comprehensive negative workup for multiple myeloma initially, including a bone marrow biopsy and hematologic workup, the disease progressed to multiple myeloma following definitive radiation therapy, as evidenced by the development of hypermetabolic lytic lesions and further pathological examination. The patient's treatment course included systemic chemotherapy and an autologous stem cell transplant, resulting in a favorable treatment response. The progression to multiple myeloma despite established guidelines highlights the need for close observation and the potential for innovative therapeutic strategies to manage this rare entity.

Hashimoto Thyroiditis Coexisting With Breast Fibroadenoma.

A 34-year-old female with co-existing multiple breast nodules being treated simultaneously presented to the outpatient clinic with fatigue as the chief complaint which had progressively worsened over one year. Ultrasound showed a heterogeneous parenchymal ectopic pattern suggestive of thyroiditis, with no suspicion of nodules and cysts. Laboratory results showed raised levels of thyroid-stimulating hormone (TSH), serum anti-thyroglobulin antibody, and serum thyroid peroxidase antibody. Levothyroxine sodium at a dosage of 50 µg/day was prescribed to the patient, following which the patient had normal TSH levels on follow-up after two months. Simultaneously the patient was under investigation for the breast nodules that were seen as the patient's medical history when she presented to the endocrinology clinic. She was diagnosed with fibroadenoma with a canalicular pattern, without ductal atypia in both breasts and malignancy.

Retrospective Evaluation of Bone Metastases in Patients With Thyroid Malignancy: A Single-Center Experience.

Background Thyroid cancer is one of the five most common cancers causing bone metastasis. If there is an increase in serum thyroglobulin-antithyroglobulin levels in differentiated thyroid cancer or calcitonin levels in medullary thyroid cancer, patients should be evaluated for recurrence and distant metastasis. The skeleton is the second most common site of distant metastasis in thyroid cancer after the lung. Bone metastases cause pain, fractures, and spinal cord compression, severely reducing the quality of life. They are associated with poor prognosis. Bone metastases severely reduce the quality of life. This study aimed to retrospectively evaluate the diagnosis and follow-up of patients with thyroid cancer with bone metastases diagnosed at our center. Methodology A total of 1,390 patients diagnosed with thyroid malignancy at our center between 2010 and 2023 were reviewed retrospectively. The study included 27 patients with differentiated and medullary thyroid cancer who had bone metastases. Results Of 27 patients, 19 (70.4%) had differentiated and eight (29.6%) had medullary thyroid cancer. Papillary thyroid cancer constituted 22.2% (n = 6) and follicular thyroid cancer constituted 14.8% (n = 4) of the cases. Papillary carcinoma follicular variant, oncocytic, and poorly differentiated thyroid cancer were diagnosed with similar frequency, each accounting for 11.1% (n = 3). It was found that vertebrae were most commonly involved, followed by the pelvis, sternum, costae, femur and patella, shoulder and humerus, cranium, and scapula. The five-year survival rate was 72%, and the 10-year survival rate was 53%. Conclusions The number of patients with papillary cancer was the highest, but the rate of bone metastases was the lowest in this group. The highest rate of bone metastases was found in patients with poorly differentiated, oncocytic, medullary, follicular, and papillary cancer, respectively. The results obtained in this study reveal the necessity and importance of bone metastasis evaluation in patients with thyroid cancer.

Arrested Descent of the Thyroid: A New Manifestation of Abnormal Thyroid Embryology.

In this article, we review the normal embryology of the thyroid gland, categorize the ways in which this embryology can fail, and describe how those failures manifest clinically and radiologically. Finally, we describe a new manifestation of abnormal thyroid embryology. Laryngoscope, 134:995-997, 2024.

Paving the path toward multi-omics approaches in the diagnostic challenges faced in thyroid pathology.

INTRODUCTION: Despite advancements in diagnostic methods, the classification of indeterminate thyroid nodules still poses diagnostic challenges not only in pre-surgical evaluation but even after histological evaluation of surgical specimens. Proteomics, aided by mass spectrometry and integrated with artificial intelligence and machine learning algorithms, shows great promise in identifying diagnostic markers for thyroid lesions. AREAS COVERED: This review provides in-depth exploration of how proteomics has contributed to the understanding of thyroid pathology. It discusses the technical advancements related to immunohistochemistry, genetic and proteomic techniques, such as mass spectrometry, which have greatly improved sensitivity and spatial resolution up to single-cell level. These improvements allowed the identification of specific protein signatures associated with different types of thyroid lesions. EXPERT COMMENTARY: Among all the proteomics approaches, spatial proteomics stands out due to its unique ability to capture the spatial context of proteins in both cytological and tissue thyroid samples. The integration of multi-layers of molecular information combining spatial proteomics, genomics, immunohistochemistry or metabolomics and the implementation of artificial intelligence and machine learning approaches, represent hugely promising steps forward toward the possibility to uncover intricate relationships and interactions among various molecular components, providing a complete picture of the biological landscape whilst fostering thyroid nodule diagnosis.

The Relationship Between American College of Radiology Thyroid Imaging Reporting and Data System (ACR TIRADS) and Fine Needle Aspiration Cytology (FNAC) ; in Geriatric Thyroid Pathologies.

Introduction: The world population is getting older with each passing year.Thyroid cancer is the most common endocrinological cancer and its incidence is increasing in all populations. Although the increase in prevalence has been attributed more to the increased use of imaging methods and to the higher sensitivity of ultrasonography (USG) by some authorities, there are also studies suggesting a real increase.In our study, it was aimed to examine the USG and fine needle aspiration cytology (FNAC) results of thyroid nodules in the geriatric age group and to discuss them in the light of the literature. Methods: Files of 129 geriatric patients with thyroid nodules detected in the University Of Health Sciences Adana City Training and Research Hospital between 2018 and 2020 were retrospectively analyzed.The USG characteristics of the patients were categorized by scoring according to the ACR TIRADS system. FNAC diagnoses were grouped according to the Bethesda classification. Results: According to the ACR TIRADS grading, 4 patients (3.1%) were benign, 58 patients (45%) were not suspicious, 38 patients (29.5%) were mildly suspicious, 25 patients (19.4%) were moderately suspicious, and 4 patients (3.1%) were highly suspicious.In our study, although USG provided very valuable information in the approach to thyroid nodules, no relationship was found between TIRADS in the geriatric age group and FNAC results in our study (p = 0.117). Conclusion: We think that the approach to thyroid nodules in geriatric patients requires closer follow-up not only with USG data but also with clinical and history-based findings. Supplementary Information: The online version contains supplementary material available at 10.1007/s12070-022-03215-w.

Aliens in the thyroid gland: The secondary lesions.

BACKGROUND: A secondary lesion in the thyroid gland is a rare clinical scenario diagnosed preoperatively during the evaluation of a neck mass, postoperatively in a thyroidectomy specimen or in autopsy studies. Even though the thyroid gland is highly vascular, secondary malignant lesions are rare accounting for 0.2% of all thyroid malignancies. Thyroid gland secondary lesions are often metachronous in presentation as they are seldom evaluated in the initial diagnostic workup of the primary lesion. Fine-needle aspiration cytology (FNAC) is a useful modality for the diagnosis of secondary thyroid lesions. MATERIALS AND METHODS: A 6-year retrospective review (2016-2021) was carried out to assess the secondary lesions in the thyroid gland. Papanicolaou and field-stained FNAC smears of secondary thyroid lesions were reviewed. Ancillary techniques were performed on the cell block for differentiating from the primary thyroid gland lesions. RESULTS: There were 383 patients in our archives. There were only 18 cases (4.7%) that presented with secondary neoplastic lesions in the thyroid gland either by direct extension, metastases or as a hematolymphoid malignancy. There were 14 (77.7%) cases that presented with non-hematolymphoid secondary lesions while 4 (22.3%) cases presented with hematolymphoid malignancies. Thyroid secondaries were predominantly seen in female patients (female: male ratio of 1.5:1). Most of the cases presented with a synchronous secondary lesion (n = 14, 77.7%) and few metachronous secondary lesions were also noted (n = 4, 22.3%). CONCLUSION: Although exceedingly rare, the detection of secondary thyroid gland lesions is important for staging and planning treatment.

Thyroid pathology, a clue to PTEN hamartoma tumor syndrome.

Phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome (PHTS) is a hereditary disorder caused by germline inactivating mutations in the PTEN tumor suppressor gene. As a type of PHTS, Cowden syndrome is associated with abnormalities of the thyroid, breast, uterus, and gastrointestinal tract. A 52-year-old-woman visited the outpatient clinic of our endocrinology clinic with multiple thyroid nodules and Hashimoto's thyroiditis. Computed tomography imaging revealed a multinodular mass measuring up to 3.5 cm in the left thyroid lobe, causing laryngotracheal airway displacement. The total thyroidectomy specimen revealed multiple follicular adenomas and adenomatous nodules with lymphocytic thyroiditis and lipomatous metaplasia in the background. The patient was suspected of PTHS based on her thyroid pathology, family history, and numerous hamartomatous lesions of the breast, uterus, and skin. Her diagnosis was confirmed through molecular testing. This case demonstrates that pathologists must be well acquainted with thyroid pathology in PHTS.

Pediatric Thyroidectomy: Experience From a Portuguese Hospital.

Background and objective Pediatric thyroid disease requiring surgery is rare. Thyroid nodules are a frequent indication for surgery and are mostly benign. However, up to 25% of cases can be malignant. In this study, we aimed to describe our center's experience with regard to pediatric thyroid surgery. Methods This was a retrospective transverse study involving pediatric patients who underwent thyroid surgery at a tertiary hospital between January 2010 and December 2021. Results A total of 14 patients underwent 15 surgeries. The main reason for referral to pediatric endocrinology was thyroid nodules (n=10). Thirteen fine needle aspirations (FNAs) were performed, with follicular tumor (n=6) being the most common finding. The median age of patients at surgery was 15.9 years [interquartile range (IQR): 14.0-16.8]. The most common surgical indications were the presence of a follicular tumor on FNA (n=5) and thyroid nodule size causing symptoms (n=5). There was one case of prophylactic thyroidectomy due to the identification of a multiple endocrine neoplasia type 2A (MEN2A) mutation. The most frequently described histopathology results were follicular adenoma (n=6) and colloid nodular goiter (n=6). Three postoperative complications were observed in three different patients: bilateral lesion of the recurrent laryngeal nerve, cervical hematoma, and transient hypoparathyroidism with hypocalcemia. Conclusion In our study, the most frequent surgical indication was a follicular tumor. A good correlation was found between FNA cytology and final histopathology results, which is in accordance with previous studies. This reinforces the importance of FNA in diagnosis and surgical planning. The rate of complications in our study is comparable to that in larger single-center series in the literature.

Clinical value of molecular markers as diagnostic and prognostic tools to guide treatment of thyroid cancer.

OBJECTIVE: Advances in our understanding of the molecular biology of thyroid tumours is being rapidly translated into their clinical management. This review summarizes the current use of molecular testing in thyroid tumours, focusing on their usefulness as diagnostic and prognostic tools to guide treatment with consideration of present limitations. DESIGN: Considerations about molecular testing applications for the diagnosis and treatment of thyroid tumours are divided into four sections/roles: (1) evaluating cytologically indeterminate thyroid nodules; (2) guiding extent of surgery in indeterminate thyroid nodules; (3) completing histological characterization of thyroid tumours and (4) identifying actionable mutations in advanced progressive thyroid cancers. RESULTS: Genomic testing can improve the presurgical malignancy risk assessment in indeterminate thyroid nodules. However, a prior in-depth analysis of institutional quality and outcomes of sonographical, cytological and histological characterization of thyroid tumours is necessary. Presently, it remains uncertain whether knowing the molecular profile of a cytologically indeterminate thyroid nodule might be advantageous to modify the extent of initial surgery. Molecular characterization of thyroid tumours can be a valuable adjunct to morphological diagnosis in some challenging cases, such as in low-risk follicular cell-derived neoplasms, or rare tumours. Finally, as selective kinase inhibitors are available, molecular testing in locally advanced/metastatic progressive thyroid cancers should also be integrated into the institutional clinical management pathway to improve outcomes and limit toxicity. CONCLUSIONS: Molecular testing needs to be implemented into the local evidence-based clinical management thyroid nodule/cancer pathways to improve its diagnostic and prognostic value and to optimize cost-effectiveness.

An Aggressive Form of Medullary Thyroid Carcinoma-Melanocytic Subtype: A Case Report.

Medullary thyroid cancer (MTC) represents a small proportion of thyroid cancers. In MTC, melanin production is extremely uncommon. Few case reports have documented this rare variant, and follow-up on these cases has been very limited. Our case studies a 51-year-old female who initially presented with goiter. This tumor recurred multiple times despite surgery with rapid growth and poor response to radiotherapy. Microscopic examination showed high-grade malignant neoplasm with lymphocytic differentiation. Immunohistochemical studies were diffusely positive for S100, SOX10, and Melan-A. Histology confirmed melanocytic medullary carcinoma that had undergone a high-grade transformation with loss of epithelial and neuroendocrine expression. Due to the scarcity and rarity of this subtype, further evaluation and case studies are needed for further categorization and prognostication.

Correlación ultrasonográfica entre volumen tiroideo y ti-rads. Estudio prospectivo / Ultrasonographic correlation between thyroid volume and ti-rads. Prospective study

La comunidad científica se ha preocupado por cuantificar el volumen tiroideo según variables como sexo, edad y deficiencias de yodo asociadas, sin embargo, pese al uso globalizado de TI-RADS para estimación de riesgo de malignidad en la patología tiroidea, no existe suficiente información en relación a si el tamaño de la glándula guarda o no relación con esta escala. Objetivo: comparar el Volumen Tiroideo con TI-RADS en pacientes atendidos en la unidad de ecografía diagnóstica del Centro Clínico Naguanagua en el período enero 2022 - enero 2023. Métodos: estudio observacional-descriptivo de nivel comparativo, con diseño transversal y prospectivo. Muestra no probabilística censal, abarcando la totalidad de los pacientes a los cuales se les efectuó ecografía tiroidea en el período establecido. Se efectuó un registro en cuanto a la cuantificación del volumen de: lóbulo tiroideo derecho, lóbulo tiroideo izquierdo y total de tiroides, TI-RADS, edad y sexo del paciente. Se utilizó el estadístico ANOVA y se empleó el programa Statistical® de licencia libre. Resultados: muestra de 126 pacientes, con edad promedio de 51,71 años ± 1,44, mediana de 53 años. Cuando se comparó el Volumen Total de Tiroides con TI-RADS, se constató que el mayor promedio lo registraron aquellos pacientes clasificados como 4B (p <0,05). Conclusión: aun cuando se registran mayores promedios de volumen total glandular en pacientes con hallazgos nodulares, llama la atención que entre los datos registrados existan pacientes con valores muy similares a lo reportado en la literatura como volúmenes normales en presencia de patología nodular tiroidea(AU)

The scientific community has been concerned with quantifying thyroid volume according to variables such as sex, age, and associated iodine deficiencies; however, despite the global use of TI-RADS to estimate the risk of malignancy in thyroid pathologies, there is not enough information in regarding whether or not the size of the gland is related to this scale. Objective: to compare the Thyroid Volume with TI-RADS in patients treated in the diagnostic ultrasound unit of the Naguanagua Clinical Center in the period January 2022 - January 2023. Methods: observational-descriptive study of a comparative level, with a crosssectional and prospective design. Non-probabilistic census sample, covering all the patients who underwent thyroid ultrasound in the established period. A record was made regarding the quantification of the volume of: right thyroid lobe, left thyroid lobe and total thyroid, TI-RADS, age and sex of the patient. The ANOVA statistic was used and the free license Statistical® program was used. Results: sample of 126 patients, mean age 51.71 ± 1.44 years, median 53 years. When the Total Thyroid Volume was compared with TI-RADS, it was found that the highest mean was registered by those patients classified as 4B (p <0.05). Conclusion: even when higher total glandular volume averages are recorded in patients with nodular findings, it is noteworthy that among the recorded data there are patients with values very similar to those reported in the literature as normal volumes in the presence of thyroid nodular pathology(AU)

Vitiligo-Thyroid Disease Association: When, in Whom, and Why Should It Be Suspected? A Systematic Review.

In most dermatological pathologies, the phenomena observed on the skin are a reflection of internal disorders. In patients with associated acral involvement on the dorsal sides of the hands, this "vitiligo phenotype" may lead to the investigation of certain associated pathologies that sometimes have no obvious clinical impact. To assess the link between skin depigmentation and autoimmune pathologies, we conducted a systematic review involving article selection from the PubMed database. Patients with coexisting thyroid pathologies were found to have a predisposition for developing acral vitiligo and depigmentation of the wrists, and autoimmune thyroid pathologies appeared to be the only coexisting autoimmune or inflammatory diseases in vitiligo patients to show a pattern of distribution. The association of concomitant thyroid dysfunction with depigmentation of the hands was found to be so strong that the absence of depigmented macules on the hands may exclude the coexistence of an autoimmune thyroid pathology. Although the frequency of acral involvement in patients with vitiligo and autoimmune pathologies is higher, the mechanism by which thyroid dysfunction influences this distribution pattern remains incompletely elucidated and requires future studies.

Harnessing the Power of Artificial Intelligence in Otolaryngology and the Communication Sciences.

Use of artificial intelligence (AI) is a burgeoning field in otolaryngology and the communication sciences. A virtual symposium on the topic was convened from Duke University on October 26, 2020, and was attended by more than 170 participants worldwide. This review presents summaries of all but one of the talks presented during the symposium; recordings of all the talks, along with the discussions for the talks, are available at https://www.youtube.com/watch?v=ktfewrXvEFg and https://www.youtube.com/watch?v=-gQ5qX2v3rg . Each of the summaries is about 2500 words in length and each summary includes two figures. This level of detail far exceeds the brief summaries presented in traditional reviews and thus provides a more-informed glimpse into the power and diversity of current AI applications in otolaryngology and the communication sciences and how to harness that power for future applications.

Alemtuzumab-Induced Autoimmune Thyroid Dysfunction.

Alemtuzumab, a humanized monoclonal antibody used as a disease-modifying treatment in relapsing-remitting multiple sclerosis (RRMS), frequently causes autoimmunity as its principal adverse effect. We describe a typical case of a young man treated with two courses of alemtuzumab presenting 18 months later with initial hyperthyroidism due to Graves' disease (GD) followed by persistent hypothyroidism. We discuss the pathophysiological role of stimulating and blocking thyrotropin receptor antibodies in the development of alemtuzumab-induced autoimmune thyroid dysfunction and clinical challenges posed by spontaneous, bidirectional switching between hyperthyroidism and hypothyroidism. Guidelines recommend monitoring thyroid function pre-treatment and every three months for four years following alemtuzumab treatment. Patient education is crucial for maintaining adherence to monitoring programs.

Allan-Herndon-Dudley Syndrome: A Novel Pathogenic Variant of the SLC16A2 gene.

Allan-Herndon-Dudley syndrome (AHDS) is a rare disorder characterized by thyroid irregularities, neurological issues, and developmental delay. In this article, we reported a patient with AHDS who presented with severe developmental delay and failure to thrive in the setting of thyroid irregularities. The patient had missense mutations in the SLC16A2 gene, which codes for monocarboxylate transporter 8 (MCT8). We identified two single-nucleotide variants, including guanine to alanine substitution at position +1 of intron 5 (IVS5+1 G>A) and guanine to alanine substitution at position 1400 of intron 1 (c.1400G>A). This variant has not been previously reported as pathogenic in a patient diagnosed with AHDS, as missense and in-frame single amino-acid deletions have not generally been associated with severe neurodevelopment sequela. We review the clinical and laboratory findings of this rare condition. We will discuss the value of early recognition and diagnosis based on promising clinical trials to treat the neurological and developmental sequela associated with AHDS.

The Unlikely Suspect: A Case Report of New-Onset Hyperthyroidism Due to Graves' Disease in an 89-Year-Old Gentleman and Review of Literature.

Thyroid dysfunction in the elderly commonly manifests as hypothyroidism. With advancing age, toxic nodules are the more common cause of hyperthyroidism as compared to Graves' disease. Due to the lack of classical symptoms of hyperthyroidism in the elderly, the diagnosis can often be delayed. Previously, an 82-year-old gentleman with oropharyngeal dysphagia due to Graves' disease was the oldest reported case with atypical symptoms. We report a case of an 89-year-old gentleman with no prior history of thyroid disease, who presented with non-specific gastrointestinal symptoms that ultimately led to the diagnosis of hyperthyroidism secondary to Graves' disease. We also review the available literature regarding the pathophysiology, clinical presentation, and management of hyperthyroidism and Graves' disease in the elderly.

Metabolic Profile Characterization of Different Thyroid Nodules Using FTIR Spectroscopy: A Review.

Thyroid cancer's incidence has increased in the last decades, and its diagnosis can be a challenge. Further and complementary testing based in biochemical alterations may be important to correctly identify thyroid cancer and prevent unnecessary surgery. Fourier-transform infrared (FTIR) spectroscopy is a metabolomic technique that has already shown promising results in cancer metabolome analysis of neoplastic thyroid tissue, in the identification and classification of prostate tumor tissues and of breast carcinoma, among others. This work aims to gather and discuss published information on the ability of FTIR spectroscopy to be used in metabolomic studies of the thyroid, including discriminating between benign and malignant thyroid samples and grading and classifying different types of thyroid tumors.

Association between exposure to radioactive iodine after the Chernobyl accident and thyroid volume in Belarus 10-15 years later.

BACKGROUND: While there is a robust literature on environmental exposure to iodine-131 (131I) in childhood and adolescence and the risk of thyroid cancer and benign nodules, little is known about its effects on thyroid volume. METHODS: To assess the effect of 131I dose to the thyroid on the volume of the thyroid gland, we examined the data from the baseline screening of the Belarusian-American Cohort Study of residents of Belarus who were exposed to the Chernobyl fallout at ages ≤18 years. Thyroid dose estimates were based on individual thyroid activity measurements made shortly after the accident and dosimetric data from questionnaires obtained 10-15 years later at baseline screening. During baseline screening, thyroid gland volume was assessed from thyroid ultrasound measurements. The association between radiation dose and thyroid volume was modeled using linear regression where radiation dose was expressed with power terms to address non-linearity. The model was adjusted for attained age, sex, and place of residence, and their modifying effects were examined. RESULTS: The analysis was based on 10,703 subjects. We found a statistically significant positive association between radiation dose and thyroid volume (P < 0.001). Heterogeneity of association was observed by attained age (P < 0.001) with statistically significant association remaining only in the subgroup of ≥18 years at screening (P < 0.001). For this group, increase in dose from 0.0005 to 0.15 Gy was associated with a 1.27 ml (95% CI: 0.46, 2.07) increase in thyroid volume. The estimated effect did not change with increasing doses above 0.15 Gy. CONCLUSIONS: This is the first study to examine the association between 131I dose to the thyroid gland and thyroid volume in a population of individuals exposed during childhood and systematically screened 10-15 years later. It provides evidence for a moderate statistically significant increase in thyroid volume among those who were ≥ 18 years at screening. Given that this effect was observed at very low doses and was restricted to a narrow dose range, further studies are necessary to better understand the effect.