Epidemiological, Clinical, Laboratory, and Radiological Characteristics of Children and Adolescents Diagnosed with Hashimoto's Thyroiditis: A Single-Center Experience.

Objective: This study aimed to investigate the epidemiological, clinical, laboratory, and radiological characteristics of children diagnosed with Hashimoto's thyroiditis and to present the experiences of a referral center. Materials and Methods: This study included 200 pediatric patients diagnosed with Hashimoto's thyroiditis between January 2020 and May 2024 at a single center. The data were extracted and compiled from the participants' medical records, including clinical information, physical examination findings, laboratory test results, and radiological imaging. Results: Mean age of the study population was 11.3 ± 3.2 years at diagnosis, with a female predominance. At the time of clinical presentation, 8.5% of the study participants were 6 years of age or younger. The majority of patients, comprising 39.5% of the cohort, exhibited euthyroid thyroid function. Additionally, 33.5% of the patients were classified as having subclinical hypothyroidism, 22% demonstrated overt hypothyroidism, and 5% presented with hyperthyroidism. Approximately one-third of the study participants were referred for further evaluation due to the identification of abnormal thyroid function test results during routine screening examinations. 48% of the patients had a documented family history of thyroid disease. At diagnosis, 39.5% were prepubertal. The rate of overt hypothyroidism was higher in prepubertal patients compared to pubertal patients (41.8% vs. 9.1%, P < .005). Mean gland volume SDS was 2.61 ± 3.69, and 45.5% had goiter. Thyroid nodular lesions were identified in 5.5% of the study participants. Fine-needle aspiration biopsy was performed on five patients, revealing benign findings in three cases and atypia of undetermined significance in the remaining two cases. Conclusion: Patints with subclinical hypothyroidism who have a baseline TSH level exceeding 8.5 mIU/L at initial presentation and do not receive treatment are likely to progress to overt hypothyroidism during subsequent follow-up. Prepubertal cases were more frequently observed compared to previous reports, and the course of hypothyroidism was more severe in prepubertal patients. These findings suggest a potential shift towards earlier onset of autoimmunity in children. Further studies are warranted to substantiate this observation.