Differentiated thyroid carcinoma in children and adolescents

BACKGROUND: Thyroid nodules in children are relatively rare; the risk of malignancy is considerably higher compared to adults. The optimal extent of surgery, the indications for radioactive iodine therapy (RAI), and the role of molecular genetic testing in children with thyroid carcinoma remain a matter of debate. AIM: To investigate the clinical course of differentiated thyroid carcinoma (DTC) in children, as well as the outcomes of surgical and combined treatment based on ten years clinical experience at the Endocrinology Research Centre. MATERIALS AND METHODS: This retrospective single-center study included 980 pediatric and adolescent patients who underwent surgery for thyroid nodules between 2015 and 2024. The diagnostic protocol comprised history taking, physical examination, thyroid ultrasound, fine-needle aspiration biopsy, and postoperative histopathological evaluation. Molecular genetic testing was performed in children with a family history or suspected syndromic forms of thyroid carcinoma. The median follow-up duration for patients with DTC was 12 months [1.0; 36.0]. RESULTS: Malignant thyroid tumors were identified in 506 patients (51.6%), the majority of them - differentiated thyroid carcinoma (DTC) (n=472). The most common histological type was papillary thyroid carcinoma (n=448; 88,5%). Metastatic involvement of regional lymph nodes was present in 21% of children. Adjuvant RAI was performed in 48.5% of patients; distant metastases to the lungs were detected in 5.7% of cases. Recurrences were registered in 5.1% of children; in 16.5% of children the disease persisted after primary treatment in the form of biochemical and/or structural persistence. MGI was performed in 66 children; pathogenic variants were detected in 53.1%, most frequently in the DICER1, PTEN, and APC genes. CONCLUSION: Differentiated thyroid carcinoma in children is characterized by a number of clinical and molecular genetic features, which determines the need for a specialized multidisciplinary approach to their management. The high risk of malignancy in nodules, frequent regional dissemination and peculiarities of the molecular profile argue for the necessity of early diagnosis, integration of molecular testing and personalized choice of the volume of surgical intervention in the conditions of specialized centers.