Comparison of ultrasonography and pathology features between children and adolescents with papillary thyroid carcinoma

Objective: To compare the ultrasonography and pathology features between children and ado-lescents with papillary thyroid carcinoma (PTC). Methods: A total of 53 patients who were surgically diagnosed with childhood or adolescent PTC between 2017 and 2022 were included in this study. The pre-operative ultrasonography, post -operative histology, and molecular and clinical characteristics were retrospectively analyzed. Results: No differences were observed in composition, echogenicity, and shape using ultraso-nography. Moreover, there was a significantly higher rate of extrathyroidal extension, punctate echogenic foci, and lymph node metastases in children compared to adolescents. The molecular analysis showed that BRAFV600E mutations are the most prevalent abnormality in adolescent PTC (12/20, 60.0%). However, they are less in childhood PTC (7/23, 30.4%). In addition, using next-generation sequencing, three cases with oncogenic fusion (one TRIM33-RET case, one CCDC6-RET case, and one STRN-ALK case) were identified in childhood PTC. Conclusion: The frequency of extrathyroidal extension, punctate echogenic foci, and lymph node metastases were higher in childhood PTC, while BRAFV600E mutations were higher in adolescent PTC.