Endocrine Abstracts

Introduction: Differentiated thyroid cancer (DTC) is rare in the paediatric population when compared to adults. Paediatric patients often present with advanced disease at diagnosis, characterized by multifocal disease, heightened lymph node involvement, and distant metastasis. Additionally, they face a higher risk of post-operative complications in comparison to adults. Despite that, paediatric DTC exhibits an excellent prognosis.

Methods: A retrospective study was conducted, analyzing medical data of 25 individuals under 18 years diagnosed with differentiated thyroid cancer in an oncology center in Portugal from January 2013 to December 2023.

Results: Twenty-four patients were diagnosed with papillary thyroid carcinoma, and one with oncocytic thyroid carcinoma. The mean age at diagnosis was 15.28 years, and 68% of the patients were females. Histology reports indicated that at least one aggressive feature was present in 20 cases (80%). Lymph node involvement was observed in 9 patients (36%), and 2 of them had distant metastasis, both pulmonary (8%). Sixteen patients underwent total thyroidectomy and 9 had hemithyroidectomy, 5 of which later underwent surgery totalization based on the histopathological results. Lymph node dissection was initially performed in 8 individuals (33%). Post-operative complications were reported in 9 patients, including transient primary hypoparathyroidism (n=3), persistent primary hypoparathyroidism (n=6), and transient dysphonia (n=4). Sixteen patients (64%) were submitted to radioiodine therapy after surgery. Regarding follow-up, 14 patients were classified as having an excellent response (56%), 5 had an indeterminate response (20%) and the remaining ones presented either a biochemical (n=3; 12%) or structural (n=2; 8%) incomplete response. Due to persistent/recurrent disease, 2 patients had to be submitted to lymph node dissection and 4 individuals were retreated with radioiodine.

Discussion: These findings underscore the unique clinical characteristics of paediatric DTC. The relatively high prevalence of patients needing thyroidectomy totalization and lymph node dissection emphasises the need for a careful assessment when deciding the extent of thyroid surgery. In addition, the significant rates of early postoperative complications and therapy incomplete responses underline that close surveillance is crucial after surgery.