Incidence and malignancy rates of indeterminate pediatric thyroid nodules

Thyroid Fine-Needle Aspiration: The Current and Future Landscape of Cytopathology

Thyroid cytology is a rapidly evolving field that has seen significant advances in recent years. Its main goal is to accurately diagnose thyroid nodules, differentiate between benign and malignant lesions, and risk stratify nodules when a definitive diagnosis is not possible. The current landscape of thyroid cytology includes the use of fine-needle aspiration for the diagnosis of thyroid nodules with the use of uniform, tiered reporting systems such as the Bethesda System for Reporting Thyroid Cytopathology. In recent years, molecular testing has emerged as a reliable preoperative diagnostic tool that stratifies patients into different risk categories (low, intermediate, or high) with varying probabilities of malignancy and helps guide patient treatment.

Case Report: Plummer's adenoma in Prader-Willi syndrome

Thyroid nodules in children are less common than in adults but they are approximately two- to three-fold more likely to be malignant in children. Among thyroid nodular diseases, Plummer's adenoma occurs very rarely in pediatrics, and currently, there is no literature providing evidence of this diagnosis in patients with Prader-Willi syndrome (PWS). We report the case of a 9-year-old Caucasian boy affected by PWS presenting with a rapidly growing palpable mass in the thyroid lodge associated with subclinical hyperthyroidism. Laboratory and other examinations (thyroid ultrasound, fine-needle aspiration of the nodule, and scintigraphy) were strongly suggestive for Plummer's adenoma; therefore, the patient underwent left hemithyroidectomy surgery, and anatomo-pathological examination confirmed the diagnosis. Our case describes the first evidence of an isolated follicular adenoma in children with PWS. Surgery is the only therapeutic option in younger children. Further evidence is needed to assess the possible correlation between these two conditions and the existence of potential risk factors.

Application value of multi-gene mutation detection in the clinical management of pediatric papillary thyroid carcinoma: a preliminary exploration

Objectives

Thyroid cancer rarely occurs in children and adolescents. Molecular markers such as BRAF, RAS, and RET/PTC have been widely used in adult PTC. It is currently unclear whether these molecular markers have equivalent potential for application in pediatric patients. This study aims to explore the potential utility of a multi-gene conjoint analysis based on next-generation targeted sequencing for pediatric papillary thyroid carcinoma (PTC).

Materials and methods

The patients diagnosed with PTC (aged 18 years or younger) in the pediatrics department of Lishui District Hospital of Traditional Chinese Medicine were retrospectively screened. A targeted enrichment and sequencing analysis of 116 genes associated with thyroid cancer was performed on paraffin-embedded tumor tissues and paired paracancerous tissue of fifteen children (average age 14.60) and nine adults (average age 49.33) PTC patients. Demographic information, clinical indicators, ultrasonic imaging information and pathological data were collected. The Kendall correlation test was used to establish a correlation between molecular variations and clinical characteristics in pediatric patients.

Results

A sample of 15 pediatric PTCs revealed a detection rate of 73.33% (11/15) for driver gene mutations BRAF V600E and RET fusion. Compared to adult PTCs, the genetic mutation landscape of pediatric PTCs was more complex. Six mutant genes overlap between the two groups, and an additional seventeen unique mutant genes were identified only in pediatric PTCs. There was only one unique mutant gene in adult PTCs. The tumor diameter of pediatric PTCs tended to be less than 4cm (p<0.001), and the number of lymph node metastases was more than five (p<0.001). Mutations in specific genes unique to pediatric PTCs may contribute to the onset and progression of the disease by adversely affecting hormone synthesis, secretion, and action mechanisms, as well as the functioning of thyroid hormone signaling pathways. But, additional experiments are required to validate this hypothesis.

Conclusion

BRAF V600E mutation and RET fusion are involved in the occurrence and development of adolescent PTC. For pediatric thyroid nodules that cannot be determined as benign or malignant by fine needle aspiration biopsy, multiple gene combination testing can provide a reference for personalized diagnosis and treatment by clinical physicians.

Radiation Dose Does Not Affect the Predictive Value of Thyroid Biopsy for Diagnosing Papillary Thyroid Cancer in a Belarusian Cohort Exposed to Chernobyl Fallout

INTRODUCTION

The Chernobyl nuclear accident exposed residents of contaminated territories to substantial quantities of radioiodines and was followed by an increase in thyroid cancer, primarily papillary thyroid cancer (PTC), among exposed children and adolescents. Although thyroid biopsy is an essential component of screening programs following accidental exposure to radioiodines, it is unknown whether the predictive value of biopsy is affected by different levels of environmental exposure.

METHODS

A cohort of 11,732 Belarusians aged ≤18 years at the time of the Chernobyl accident with individual thyroid radiation dose estimates was screened at least once 11-22 years later. Paired cytologic conclusions and histopathologic diagnoses were possible for 258 thyroid nodules from 238 cohort members. Cytologic conclusions were divided into five reporting categories, with all follicular lesion aspirates combined into a single indeterminate category. Standard performance indicators, risk of malignancy (ROM), and odds ratios for a correct cytologic conclusion were calculated, both overall and according to quintile of thyroid radiation dose.

RESULTS

The arithmetic mean thyroid dose estimate for the study group was 1.73 Gy (range: 0.00-23.64 Gy). The final histopathologic diagnosis was cancer for 136 of 258 biopsies (52.7%; 135 papillary and 1 follicular). The overall ROM was 96.7% for cytologies definite for PTC, 83.7% for suspicious for PTC, 33.0% for indeterminate, 8.1% for benign, and 31.0% for non-diagnostic. The ROM showed little change according to level of radiation exposure. Overall, there was no association between thyroid radiation dose and the odds ratio for a correct cytologic conclusion (p = 0.24). When analyzed according to dose quintile, the odds ratio for a correct conclusion increased two-fold at 0.10-0.29 Gy compared to a dose of 0.00-0.09 Gy and decreased at doses of 0.3-24 Gy (p value for linear trend = 0.99).

CONCLUSIONS

At radiation doses received by a cohort of young Belarusians exposed to radioiodines by the Chernobyl accident, the predictive value of thyroid biopsy for diagnosing PTC was not significantly affected by level of radiation exposure.

Evolving approaches in paediatric thyroid cytopathology: A review

The guidelines for the workup of thyroid nodules have been established in adult populations and secondarily applied to paediatric populations. In particular, The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) is commonly applied to both adult and paediatric thyroid nodules. However, as paediatric nodules have distinct molecular drivers and behavioural trajectories, there is renewed interest in diagnostic and management strategies that are paediatric specific. Here, we review key differences between paediatric and adult thyroid cancer and recent literature evaluating the use of TBSRTC in paediatric populations.

Hashimoto's Thyroiditis and the Risk of Papillary Thyroid Cancer in Children

The association between Hashimoto's thyroiditis (HT) and pediatric thyroid cancer is controversial. Most studies examining this connection have been based on adults, and larger studies in children are lacking. We performed a retrospective study of all sequential pediatric patients who underwent a thyroidectomy for a neoplasm at our institution over a twenty-year period in order to explore the link between HT and pediatric thyroid cancer. A total of 153 patients, median age 16.5 (interquartile range [IQR] 14.2-18.3) years, underwent thyroid surgery for a neoplasm. Patients were mainly female (80%) and White (84%). Median follow-up was 58.6 (IQR 20.7-105.4) months. Thirty-five (23%) patients had HT. Patients who underwent thyroid surgery and had HT were more likely to harbor a malignant neoplasm (p = 0.05); specifically, papillary thyroid carcinoma (PTC, p = 0.02). There was a difference in the distribution of HT among the subtypes of PTC (p = 0.03). Despite this, there was no difference in terms of survival between patients with/without HT. In conclusion, children with a thyroid malignancy, specifically, PTC, are more likely to have HT. The association between HT and pediatric PTC appears to be subtype-specific but does not seem to affect patient survival.

Performance of ACR TI-RADS and the Bethesda System in Predicting Risk of Malignancy in Thyroid Nodules at a Large Children's Hospital and a Comprehensive Review of the Pediatric Literature

While thyroid nodules are less common in children than in adults, they are more frequently malignant. However, pediatric data are scarce regarding the performance characteristics of imaging and cytopathology classification systems validated to predict the risk of malignancy (ROM) in adults and select those patients who require fine-needle aspiration (FNA) and possibly surgical resection. We retrospectively reviewed the electronic medical records of all patients 18 years of age or younger who underwent thyroid FNA at our institution from 1 July 2015 to 31 May 2022. Based on surgical follow-up from 74 of the 208 FNA cases, we determined the ROM for the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) ultrasound risk stratification system and The Bethesda System for Reporting Thyroid Cytopathology and added our results to those of pediatric cohorts from other institutions already published in the literature. We found the following ROMs for 1458 cases using ACR TI-RADS (TR): TR1. Benign: 2.2%, TR2. Not Suspicious: 9.3%, TR3. Mildly Suspicious: 16.6%, TR4. Moderately Suspicious: 27.0%, and TR5. Highly Suspicious 76.5%; and for 5911 cases using the Bethesda system: Bethesda I. Unsatisfactory: 16.8%, Bethesda II. Benign: 7.2%, Bethesda III: Atypia of Undetermined Significance: 29.6%, Bethesda IV. Follicular Neoplasm: 42.3%, Bethesda V. Suspicious for Malignancy: 90.8%, and Bethesda VI. Malignant: 98.8%. We conclude that ACR TI-RADS levels imply higher ROMs for the pediatric population than the corresponding suggested ROMs for adults, and, in order to avoid missing malignancies, we should consider modifying or altogether abandoning size cutoffs for recommending FNA in children and adolescents whose thyroid glands are smaller than those of adults. The Bethesda categories also imply higher ROMs for pediatric patients compared to adults.

Preoperative evaluation of thyroid nodules - Diagnosis and management strategies

Thyroid cancer is the most common endocrine malignancy, with increasing incidence over the past few decades. Fine needle aspiration (FNA) biopsy is the gold standard for preoperative diagnosis of thyroid malignancies. Nevertheless, this method renders indeterminate results in up to 30% of the cases. Therefore, these patients are often referred to unnecessary surgery to establish the diagnosis. To improve the accuracy of preoperative diagnosis, several other ways, such as ultrasonography, elastography, immunohistochemical analysis, genetic testing, and core needle biopsy, have been developed and can be used either in association with or as an alternative to FNA. This review aims to evaluate all these diagnostic tools to determine the most appropriate way of managing thyroid nodules and subsequently improve the selection of cases referred to surgery.

The Complex Cyto-Molecular Landscape of Thyroid Nodules in Pediatrics

Thyroid fine-needle aspiration (FNA) is a commonly used diagnostic cytological procedure in pediatric patients for the evaluation of thyroid nodules, triaging them for the detection of thyroid cancer. In recent years, greater attention has been paid to thyroid FNA in this setting, including the use of updated ultrasound score algorithms to improve accuracy and yield, especially considering the theoretically higher risk of malignancy of these lesions compared with the adult population, as well as to minimize patient discomfort. Moreover, molecular genetic testing for thyroid disease is an expanding field of research that could aid in distinguishing benign from cancerous nodules and assist in determining their clinical management. Finally, artificial intelligence tools can help in this task by performing a comprehensive analysis of all the obtained data. These advancements have led to greater reliance on FNA as a first-line diagnostic tool for pediatric thyroid disease. This review article provides an overview of these recent developments and their impact on the diagnosis and management of thyroid nodules in children.

Cytological evaluation of thyroid nodules in children and young adults: a multi-institutional experience

PURPOSE

The utility of the Bethesda system for reporting thyroid cytopathology is debatable in determining the risk of malignancy in pediatric patients. Moreover, the upper age limit for defining the pediatric group has varied across different studies. The aim of this study is to compare the risk of malignancy (ROM) and risk of neoplasia (RON) across different Bethesda categories between the pediatric, young adult, and adult patients.

METHODS

This is a retrospective multi-institutional study performed in three Indian hospitals. ROM was calculated and compared across Bethesda categories in adult (>18 years) and pediatric age groups (≤18 years), with a subgroup analysis in young adults (19-21 years).

RESULTS

Thyroid nodules from a total of 5958 patients were subjected to fine needle aspiration. Of these 199 were pediatric (3.3%) and follow-up histology was available in 2276. The ROM and RON rates, including overall ROM/RON, were significantly higher in pediatric age group as compared to adults. Overall ROM of suspicious for malignancy and malignant categories was higher in children as compared to adults. The overall surgical resection rates were also higher in pediatric patients (45.2% vs. 35.7%; p < 0.01). The similar trend of increased ROM, RON and resection rates was seen among young adults as compared to adult age group.

CONCLUSION

Thyroid nodules presenting in children are more likely to be malignant than those in adults. Importantly, the young adult group behaved in a similar manner with regard to surgical resection rates, ROM and RON to pediatric.

Whole-exome sequencing and bioinformatic analyses revealed differences in gene mutation profiles in papillary thyroid cancer patients with and without benign thyroid goitre background

Background

Papillary thyroid cancer (PTC) is the most common thyroid malignancy. Concurrent presence of cytomorphological benign thyroid goitre (BTG) and PTC lesion is often detected. Aberrant protein profiles were previously reported in patients with and without BTG cytomorphological background. This study aimed to evaluate gene mutation profiles to further understand the molecular mechanism underlying BTG, PTC without BTG background and PTC with BTG background.

Methods

Patients were grouped according to the histopathological examination results: (i) BTG patients (n = 9), (ii) PTC patients without BTG background (PTCa, n = 8), and (iii) PTC patients with BTG background (PTCb, n = 5). Whole-exome sequencing (WES) was performed on genomic DNA extracted from thyroid tissue specimens. Nonsynonymous and splice-site variants with MAF of ≤ 1% in the 1000 Genomes Project were subjected to principal component analysis (PCA). PTC-specific SNVs were filtered against OncoKB and COSMIC while novel SNVs were screened through dbSNP and COSMIC databases. Functional impacts of the SNVs were predicted using PolyPhen-2 and SIFT. Protein-protein interaction (PPI) enrichment of the tumour-related genes was analysed using Metascape and MCODE algorithm.

Results

PCA plots showed distinctive SNV profiles among the three groups. OncoKB and COSMIC database screening identified 36 tumour-related genes including BRCA2 and FANCD2 in all groups. BRAF and 19 additional genes were found only in PTCa and PTCb. "Pathways in cancer", "DNA repair" and "Fanconi anaemia pathway" were among the top networks shared by all groups. However, signalling pathways related to tyrosine kinases were the most significantly enriched in PTCa while "Jak-STAT signalling pathway" and "Notch signalling pathway" were the only significantly enriched in PTCb. Ten SNVs were PTC-specific of which two were novel; DCTN1 c.2786C>G (p.Ala929Gly) and TRRAP c.8735G>C (p.Ser2912Thr). Four out of the ten SNVs were unique to PTCa.

Conclusion

Distinctive gene mutation patterns detected in this study corroborated the previous protein profile findings. We hypothesised that the PTCa and PTCb subtypes differed in the underlying molecular mechanisms involving tyrosine kinase, Jak-STAT and Notch signalling pathways. The potential applications of the SNVs in differentiating the benign from the PTC subtypes requires further validation in a larger sample size.

Risk factors for prolonged hospitalization and readmission after total thyroidectomy in children: Associations with surgical subspecialty

BACKGROUND

Total thyroidectomy (TT) in children is performed by pediatric general surgeons (P-GS), pediatric otolaryngologists (P-ENT), or adult GS/ENT. This study evaluated short-term pediatric TT outcomes, focusing on surgical subspecialties.

METHODS

Pediatric (<18 years) TT with/without central limited lymph node dissection (CLND) between 2015 and 2020 were obtained from the National Surgical Quality Improvement Program-Pediatric database. Risk factors for prolonged hospitalization (PH,>2 days) and 30-day readmission were investigated with multivariate logistic regression.

RESULTS

Of 1535 patients, 14% had PH and 2% were readmitted. PH rates for P-ENT vs. P-GS vs. adult were 21% vs. 11% vs. 10%, respectively. Adjusted risk of PH was higher for P-ENT (OR 1.70, p = 0.003) but similar for P-GS/adult. There was no difference for risk of readmission by subspecialty.

CONCLUSION

PH is more likely after pediatric TT performed by P-ENT, as compared to P-GS or adult surgeons. While TT may be performed safely by individual subspecialties, collaboration across specialties may further optimize outcomes.

Molecular Landscape of Pediatric Thyroid Cancer: A Review

Thyroid carcinomas (TC) are rare in the pediatric population; however, they constitute the most common endocrine malignancy. Despite some similarities with adult carcinomas, they have distinct clinical behavior and responses to therapy due to their unique pathology and molecular characteristics. The age cut-off used for defining the pediatric age group has been variable across different studies, and the universally accepted recommendations influence accurate interpretation of the available data. Moreover, factors such as radiation exposure and germline mutations have greater impact in children than in adults. Papillary TC is the most common and the most evaluated pediatric TC. Others, including follicular, poorly differentiated and medullary carcinomas, are rarer and have limited available literature. Most studies are from the West. Asian studies are primarily from Japan, with few from China, India, Saudi Arabia and Republic of Korea. This review provides a comprehensive account of the well-established and novel biomarkers in the field, including point mutations, fusions, miRNA, and thyroid differentiation genes. Familial and syndromic associations are also discussed. Current management guidelines for pediatric patients are largely derived from those for adults. An awareness of the molecular landscape is essential to acknowledge the uniqueness of these tumors and establish specific diagnostic and therapeutic guidelines.

Thyroid nodules in children and adolescents: Investigation and management

Clinically detectable thyroid nodules are less common in children than adults. However, they are associated with an increased risk of malignancy. Therefore, thorough evaluation of paediatric thyroid nodules is necessary, and an understanding of the features associated with a higher risk of malignancy is important to guide management and referral. Thyroid cancer in children differs significantly from that seen in adults in terms of genetics, presentation, response to treatment and prognosis. Children often present with more advanced disease, but the vast majority have excellent long-term prognosis. Evaluation and management of thyroid nodules and thyroid cancer require a multidisciplinary team approach and involvement of specialists with experience in this field. This review summarises investigative pathways for thyroid nodules in children and outlines current management strategies for paediatric thyroid nodules and cancer.

Malignancy Rates by Bethesda Subcategory in the Pediatric Population

INTRODUCTION

While the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) is the most widely used method for categorizing thyroid nodules, its applicability to children is often debated. We describe our institution's experience utilizing the TBSRTC and examine the rates of malignancy in our population.

METHODS

We conducted a retrospective chart review of eligible patients undergoing primary thyroidectomy at a high-volume tertiary care pediatric hospital. All patients had pre-operative fine needle aspiration.

RESULTS

Of the 112 patients in our cohort, 85 (76%) were female. The median age was 15.1 years. The patients were divided into groups based on the Bethesda categorization of the fine needle aspirations of their nodules. The percentages of patients whose resection specimens showed evidence of malignancy on the surgical pathology reports were recorded as follows: category I (n = 5): 20%, category II (n = 11): 0%, category III (n = 30): 17%, category IV (n = 13): 31%, category V (n = 17): 94% and category VI (n = 36): 100%.

CONCLUSION

Our findings indicate that the malignancy rates at our institution are comparable to those reported by other high-volume studies. When compared with the 2017 TBSRTC data, we found that our results were similar in many categories, with the exception of categories I and V.

Utility of Fine-Needle Aspirations to Diagnose Pediatric Thyroid Nodules

INTRODUCTION

Risk of malignancy for pediatric thyroid nodules classified according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) is not well defined. Correlations between risk of malignancy and ancillary clinical data remain inconclusive. We report a single institutional experience of fine-needle aspiration (FNA) to improve upon current management paradigm of thyroid nodules.

METHODS

A retrospective chart review of 575 thyroid nodules was performed of 324 patients who underwent 340 FNAs between 2008 and 2018 at the Children's Hospital of Philadelphia. Demographics, ultrasound (US) characteristics, FNA cytology, surgical pathology, and ancillary data were reviewed.

RESULTS

The rate of malignancy according to TBSRTC was 0.0% for category I, 0.8% for category II, 15.6% for category III, 54.5% for category IV, 100.0% for category V, and 100.0% for category VI. The cumulative Thyroid Imaging Reporting and Data System (TI-RADS) score was significantly correlated with benign and malignant nodules on pathology (p < 2.2e-16). Distribution of TI-RADS for cytologically indeterminate nodules with benign or malignant pathology revealed significant differences for composition (p = 3.20e-8) and echogenic foci (p = 0.005) but not for echogenicity (p = 0.445), shape (p = 0.160), margins (p = 0.220), and size (p = 0.105). Distributions of thyroid-stimulating hormone levels between benign and malignant patients was significant (p = 1.58e-3).

CONCLUSIONS

Nodules with TI-RADS scores >3 should undergo FNA, irrespective of size; surgical resection is recommended for nodules classified as TBSRTC category IV and V due to high risk of malignancy. US surveillance instead of FNA can be performed for nodules with TI-RADS scores ≤3.

Subtype of atypia on cytology and risk of malignancy in pediatric thyroid nodules

BACKGROUND

Thyroid nodules with atypia of undetermined significance (AUS) are challenging to manage because of their intermediate risk of malignancy. Subclassification of atypia can refine malignancy risk in adult AUS nodules but has not been evaluated in children.

METHODS

This was a retrospective cohort study of pediatric patients (<19 years old) who underwent fine-needle aspiration (FNA) of a thyroid nodule with resulting AUS cytology. Atypia was subclassified as nuclear only, architectural only, nuclear and architectural, or oncocytic. The primary outcome was the association between atypia subtype and malignancy. A secondary outcome was the association of atypia subtype with repeat FNA cytology.

RESULTS

Sixty-eight AUS nodules in 61 patients were analyzed. The median age at FNA was 16.2 years (range, 9.8-18.9 years). Twenty-four nodules (35%) were malignant. Nuclear atypia only was present in 17 nodules (25%), architectural atypia only was present in 27 nodules (40%), nuclear and architectural atypia was present in 20 nodules (29%), and predominantly oncocytic features were present in 4 nodules (6%). The presence of nuclear atypia was associated with a significantly increased rate of malignancy (22 of 37 [59%] vs 2 of 31 [6.5%]; P < .001), whereas architectural atypia was not associated with malignancy (P = .8). Repeat FNA was performed in 42 of 68 nodules (62%). In nodules with initial nuclear and architectural atypia, benign repeat cytology had a high false-negative rate (3 of 6; 50%).

CONCLUSIONS

Pediatric AUS nodules with nuclear atypia have a high rate of malignancy, but architectural atypia is not associated with malignancy. In nodules with nuclear atypia, repeat FNA may inform clinical decisions regarding the need for resection. In the absence of suspicious clinical features, nodules without nuclear atypia might be considered for observation rather than resection or repeat FNA.

Ultrasound criteria (EU-TIRADS) to identify thyroid nodule malignancy risk in adolescents. Correlation with cyto-histological findings

INTRODUCTION

Thyroid nodule (TN) harbouring a thyroid carcinoma are more common in paediatric than adult patients. In paediatric population, the evaluation of a TN should require specific paediatric tools for its diagnostic and therapeutic management. High-resolution ultrasonography and cytological evaluation after fine-needle aspiration biopsy (FNAB) remain the cornerstones of evaluation of TN.

OBJECTIVES

To evaluate in paediatric TN for the first time the usefulness and precision of the ultrasound criteria defined by the "Thyroid Imaging Reporting and Data System (EU-TIRADS) 2017 in adults" to establish the ultrasound indication for the practice of FNAB and stratify the risk of malignancy.

PATIENTS AND METHODS

24 paediatric patients under age 18 years with thyroid nodules were attended in the last 15 years, 24 of them (31 nodules; age: 15.2 ± 2.2 years; 18 women) met the inclusion criteria: FNAB with Bethesda classification and ultrasound with EU-TIRADS score. EU-TIRADS score were evaluated retrospectively. Fourteen patients underwent surgery and the definitive histological diagnosis was obtained, this allowed the calculations of sensitivity, specificity and positive and negative predictive values of the EU-TIRADS and Bethesda classification. Data on the largest diameters of the nodules were collected.

RESULTS

Of the overall 31 nodules, the distribution by EU-TIRADS (T) category was: T1 (3.2%), T2: 2 (6.4%), T3: 7 (22.6%), T4: 16 (51.6%) and T5: 5 (16.1%). All malignant nodules were included in EU-TIRADS category 4 or 5. By the other hand, 13 of the 25 benign nodules were also included in the EU-TIRADS 4 category, and one in the 5. The distribution by categories of Bethesda's classification (B): BI: 6 (19.4%), BII: 14 (45.2%), BIII: 5 (16.1%), BIV: 2 (6.5%), BV: 0 and BVI: 4 (12.9%). The pathological diagnosis of the 14 patients who underwent surgery was: 6 papillary carcinomas and 8 with benign lesions: 6 nodular hyperplasia and 2 follicular adenoma. The percentage of malignancy was 42%. The sensitivity of the EU-TIRADS classification to detect malignant nodules was 100%, the specificity was 25%, PPV 44% and NPV 100%. The sensitivity of the Bethesda classification to detect malignant nodules was 86%, the specificity was 75%, PPV 67% and NPV 90%. The analysis of the largest diameter of the nodules did not show statistically significant differences between benign and malignant lesions.

CONCLUSIONS

EU-TIRADS for ultrasonographic criteria classification in combination with the clinical history is an adequate and reproducible method to estimate suspicion of malignancy of paediatric TN. It is also a reliable diagnostic tool to decide which nodules will be candidates for FNAB.

Predictive factors of malignancy in pediatric patients with thyroid nodules and performance of the Italian classification (SIAPEC 2014) in the outcome of the cytological FNA categories

PURPOSE

The rate of malignancy (ROM) among pediatric studies using the Bethesda System is 39.5% and 41.5% for atypia of undetermined significance/follicular lesion of undetermined significance and for suspected follicular neoplasm, respectively. Data reported on the basis of Bethesda System showed lower ROM in adults with indeterminate nodules (30.5 and 28.9% respectively). Studies on adults based on the Italian Society of Anatomic Pathology and Cytology (SIAPEC) classification, report ROM of 14.2% for TIR3a and 44.6% for TIR3b category, showing greater sensitivity in detecting malignancy. To date, no performance data are available about SIAPEC classification in pediatric age.

METHODS

Retrospective data were collected from 200 pediatric subjects with thyroid nodules in the period 2000-2020.

RESULTS

The distribution of cytological categories after fine needle aspiration biopsy (FNAB) was 7 TIR1, 4 TIR1c, 22 TIR2, 14 TIR3a, 9 TIR3b, 3 TIR4, and 16 TIR5. The surgical approach was performed in 40/200 subjects, with total ROM of 65% (0% for TIR1-TIR3a, 77.8% for TIR3b, and 100% for TIR4-TIR5). Total FNAB accuracy was 95%, while the sensibility and specificity were 92.3 and 92.6%, respectively.

CONCLUSIONS

The reported data seem to confirm a greater sensitivity of SIAPEC classification to identify malignancy within the indeterminate category also in pediatric age and not only in adulthood. This finding may orient clinicians toward clinical follow-up for the indeterminate TIR3a group and toward surgical approach with total thyroidectomy in the indeterminate TIR3b group, although this indication should be confirmed in further national multicenter studies including larger cohorts.

Thyroid Cancer Risk Factors in Children with Thyroid Nodules: A One-Center Study

Thyroid nodules are common in the adult population (13%), but in childhood, they are relatively rarely diagnosed (0.2–5%). The risk factors and diagnostic and therapeutic algorithms are well-known and effectively used in adults, but no clear procedures supported by scientific research are available in the pediatric population. Our aim in this study was to identify predictive factors for thyroid cancer in a pediatric population. We retrospectively analyzed 112 children (80 girls and 32 boys, aged 0.6–18 years, with an average group age of 13.4 ± 4.5 years) with thyroid nodules who presented or were referred between 2010 and 2021. A total of 37 children qualified for partial or total thyroidectomy. After histopathological nodule examination, the most common cases were benign lesions in 23 patients (57.5%) and malignant lesions in 14 children (32.5%). Solitary benign thyroid nodules were found in 16 children (40%). Malignancy risk was higher in children with increased nodule diameter (greater than 7 mm; p = 0.018) or hypoechogenic lesions in ultrasound (p = 0.010), with no correlation between increased blood flow in the vessels and tumor diagnosis. The relative risk of developing thyroid cancer for class III was found to be higher in comparison to adults and 11.1 times higher than for classes I and II combined.

Clinical, sonographical, and pathological findings of pediatric thyroid nodules

Thyroid nodules are less frequent in children than in adults. A higher rate of malignancy is highlighted in this group. We aimed to analyze the clinical, laboratory, and ultrasound (US) findings of children and adolescents with benign and malignant thyroid nodules. This was a retrospective review of children and adolescents evaluated at a tertiary pediatric institution between 2007 and 2019. Patients with autonomously functioning nodules, autoimmune thyroid diseases, and a history of oncohematological disorders were excluded. A total of 102 patients with 131 nodules were identified. The study population included 57 females (55.9%); the average age was 10.6 ±4 years. Thirty-five nodules (26.7%) ranging 4.5-36 mm had a fine-needle aspiration (FNA) done: 45.7% (n = 16) were benign, 11.4% (n = 4) were classified as atypia, and 8.5% (n = 3) were consistent with papillary carcinoma. Fourteen patients (13.7%) underwent surgery. Five (4.9%) were finally diagnosed with papillary thyroid cancer. Of the 6 patients with benign FNAs, all except one, which was initially reported as atypia by an earlier FNA but was later diagnosed with papillary carcinoma, had a colloid nodular goiter. Of the 3 patients with atypia FNAs, one was found to be papillary carcinoma. One hundred twenty-five benign nodules (21 based on cytology and/or histology, 104 on clinical and imaging follow-up) were diagnosed. Nodule size, microcalcifications, solid parenchyma, and pathologic lymph node alterations were associated with malignancy, but nodule growth was not.Conclusion: Diagnostic approach and management of children with thyroid nodules should be based on a stepwise evaluation including clinical, laboratory, and US findings. Of the 102 patients identified, 4.9% had thyroid carcinoma below the range described in previous literature. What is Known: • Thyroid nodules are less frequent in children than in adults but more frequently malignant. Research on factors associated with malignancy have mostly been conducted in adults; further studies in pediatric thyroid nodules are warranted. What is New: • Microcalcifications, pathologic lymph node alterations, solid parenchyma, and larger nodule size are associated with malignant nodules, but nodule growth is not always suggestive of thyroid malignancy. The incidence of thyroid malignancy in this population was below the reported worldwide incidence in children with thyroid nodules.

The Use of the Bethesda System for Reporting Thyroid Cytopathology in Pediatric Thyroid Nodules: A Meta-Analysis

Background: Little is known about the application of the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) in pediatric thyroid nodules. This meta-analysis was aimed to investigate the use of TBSRTC in the pediatric population. Methods: Relevant articles were searched in PubMed and Web of Science. Meta-analysis of proportion and its 95% confidence interval (CI) were computed utilizing the random-effect model. We used subgroup analyses and meta-regression to explore the sources of heterogeneities. Egger's regression test and funnel plot visualization were used to examine publication bias. Results: We included 17 articles comprising of 3687 pediatric thyroid nodules for meta-analyses. TBSRTC outputs including frequency and risk of malignancy (ROM) for the majority of categories were not statistically different from recently published meta-analysis of 145,066 thyroid nodules in adult patients. The resection rate (RR) in the pediatric group was significantly higher in most of the categories compared with published adult data: benign, 23.2% [CI = 18.6-27.9] vs. 13.0% [CI = 9.5-16.5]; atypia of undetermined significance/follicular lesion of undetermined significance, 62.6% [CI = 50.3-74.9] vs. 36.2% [CI = 29.9-42.5]; follicular neoplasm/suspicious for follicular neoplasm, 84.3% [CI = 75.2-93.4] vs. 60.5% [CI = 54.5-66.5]; and suspicious for malignancy, 93.8% [CI = 90.1-97.6] vs. 69.7% [CI = 64.0-75.5]. Conclusion: TBSRTC is a valuable tool to make clinical decisions for pediatric patients with thyroid nodules. Pediatric patients with benign and indeterminate thyroid nodules had a higher RR than adult counterpart, but ROM of these categories in adults and children was not statistically different suggesting a potential risk of overtreatment in pediatric patients. Determining the best treatment guidelines and additional tools for risk stratification must be a top priority to precisely identify the target patient groups for surgical intervention.

Application of the Bethesda System for Reporting Thyroid Cytopathology in the Pediatric Population

OBJECTIVES

We aimed to provide the Asian experience with the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) in pediatric thyroid nodules.

METHODS

Consecutive thyroid fine-needle aspirates (patient age, ≤18 years) were retrospectively collected from 7 tertiary centers in 5 Asian countries.

RESULTS

Of 194,364 thyroid aspirates, 0.6% were pediatric cases (mean age, 15.0 years). Among 827 nodules with accessible follow-up, the resection rate and risk of malignancy (ROM) were 36.3% and 59.0%, respectively. Malignant nodules (n = 179) accounted for 59.7% of resected nodules and 21.6% of all thyroid nodules with available follow-up. Compared with the published adult series, pediatric nodules had a higher resection rate and ROM, particularly in the indeterminate categories.

CONCLUSIONS

Our study demonstrates that Asian pediatric thyroid nodules had higher ROM than those from adults. The prototypic outputs of TBSRTC may need to be adjusted in the pediatric population.

Ultrasound criteria (EU-TIRADS) to identify thyroid nodule malignancy risk in adolescents. Correlation with cyto-histological findings

INTRODUCTION

Thyroid nodule (TN) harboring a thyroid carcinoma are more common in pediatric than adult patients. In pediatric population, the evaluation of a TN should require specific pediatric tools for its diagnostic and therapeutic management. High-resolution ultrasonography and cytological evaluation after fine-needle aspiration biopsy (FNAB) remain the cornerstones of evaluation of TN.

OBJECTIVES

To evaluate in pediatric TN for the first time the usefulness and precision of the ultrasound criteria defined by the"Thyroid Imaging Reporting and Data System (EU-TIRADS) 2017 in adults" to establish the ultrasound indication for the practice of FNAB and stratify the risk of malignancy.

PATIENTS AND METHODS

24 pediatric patients under age 18 years with thyroid nodules were attended in the last 15 years, 24 of them (31 nodules; age: 15.2 ± 2.2 years; 18 women) met the inclusion criteria: FNAB with Bethesda classification and ultrasound with EU-TIRADS score. EU-TIRADS score were evaluated retrospectively. Fourteen patients underwent surgery and the definitive histological diagnosis was obtained, this allowed the calculations of sensitivity, specificity and positive and negative predictive values of the EU-TIRADS and Bethesda classification. Data on the largest diameters of the nodules were collected.

RESULTS

Of the overall 31 nodules, the distribution by EU-TIRADS (T) category was: T1 (3.2%), T2: 2 (6.4%), T3: 7 (22.6%), T4: 16 (51.6%) and T5: 5 (16.1%). All malignant nodules were included in EU-TIRADS category 4 or 5. By the other hand, 13 of the 25 benign nodules were also included in the EU-TIRADS 4 category, and one in the 5. The distribution by categories of Bethesda's classification (B): BI: 6 (19.4%), BII: 14 (45.2%), BIII: 5 (16.1%), BIV: 2 (6.5%), BV: 0 and BVI: 4 (12.9%). The pathological diagnosis of the 14 patients who underwent surgery was: 6 papillary carcinomas and 8 with benign lesions: 6 nodular hyperplasia and 2 follicular adenoma. The percentage of malignancy was 42%. The sensitivity of the EU-TIRADS classification to detect malignant nodules was 100%, the specificity was 25%, PPV 44% and NPV 100%. The sensitivity of the Bethesda classification to detect malignant nodules was 86%, the specificity was 75%, PPV 67% and NPV 90%. The analysis of the largest diameter of the nodules did not show statistically significant differences between benign and malignant lesions.

CONCLUSIONS

EU-TIRADS for ultrasonographic criteria classification in combination with the clinical history is an adequate and reproducible method to estimate suspicion of malignancy of pediatric TN. It is also a reliable diagnostic tool to decide which nodules will be candidates for FNAB.

Selected Topics in the Pathology of the Thyroid and Parathyroid Glands in Children and Adolescents

The goals of this chapter in keeping with the overall general themes of this special edition will be (1) to highlight aspects of development of the thyroid and parathyroid glands with particular focus on the role and contribution of the neural crest (or not) and how this may impact on the pathology that is seen, (2) to emphasize those lesions particularly more commonly arising in the pediatric population that actually generate specimens that the surgical pathologist would encounter, and (3) highlight more in depth specific lesions associated with heritable syndromes or specific gene mutations since the heritable syndromes tends to manifest in the pediatric age group. In this light, the other interesting areas of pediatric thyroid disease including medical thyroid diseases, congenital hypothyroidism, anatomic variants and aberrations of development that lead to structural anomalies will not be emphasized here.

The thyroid nodules in kids study (ThyNK study): An evaluation of clinical practice variation

PURPOSE

The purpose of this study was to evaluate the management of thyroid nodules in children and assess clinical practice variation (CPV) using the 2015 American Thyroid Association (ATA) guidelines as a standard.

METHODS

Pediatric patients presenting to a tertiary care pediatric centre with a thyroid nodule from 2007 to 2017 were retrospectively analyzed. Demographic and disease specific information were collected. CPV and adherence to ATA guidelines were explored.

RESULTS

Of 86 patient records reviewed, 47 (55%) were managed operatively (mean age 14.4, 59F:27M). Fifteen patients (17%) had malignant pathology, and 11/15 (73%) were papillary carcinoma. Of the 47 operative patients, 7 (15%) had no preoperative ultrasound, and 12 patients (26%) did not have preoperative cytology. All patients with low TSH had scintigraphy appropriately performed, and 1 patient with high/normal TSH did not have a preoperative FNA obtained. All differentiated thyroid cancers were appropriately managed with hemithyroidectomy or total thyroidectomy based on pathology. Where CPV from the guidelines was noted, it was associated with complex presentation, the surgeon's decision to proceed to surgery directly, and/or rare pathologies.

CONCLUSION

The ATA guidelines provide a valuable framework for the management of pediatric thyroid nodules, but CPV persists given patient/disease complexity and heterogeneity.

TYPE OF STUDY

Case Series with No Comparison Groups.

LEVEL OF EVIDENCE

Level VI: Case series with no comparison groups.

The Year in Medical Thyroidology Review: Current Challenges and Future Directions

This is a summary of the American Thyroid Association's Opening Session at the 89th Annual Meeting in October 2019. This review highlights the most clinically impactful articles in medical thyroidology published from January 2018 through September 2019.

Thyroid Cancer in the Pediatric Population

Thyroid cancer is rare in the pediatric population, but thyroid carcinomas occurring in children carry a unique set of clinical, pathologic, and molecular characteristics. In comparison to adults, children more often present with aggressive, advanced stage disease. This is at least in part due to the underlying biologic and molecular differences between pediatric and adult thyroid cancer. Specifically, papillary thyroid carcinoma (which accounts for approximately 90% of pediatric thyroid cancer) has a high rate of gene fusions which influence the histologic subtypes encountered in pediatric thyroid tumors, are associated with more extensive extrathyroidal disease, and offer unique options for targeted medical therapies. Differences are also seen in pediatric follicular thyroid cancer, although there are few studies of non-papillary pediatric thyroid tumors published in the literature due to their rarity, and in medullary carcinoma, which is most frequently diagnosed in the pediatric population in the setting of prophylactic thyroidectomies for known multiple endocrine neoplasia syndromes. The overall shift in the spectrum of histotypes and underlying molecular alterations common in pediatric thyroid cancer is important to recognize as it may directly influence diagnostic test selection and therapeutic recommendations.