Comparison of Differentiated Thyroid Cancer in Children and Adolescents with Young Adults

Differentiated thyroid cancer (DTC) is the most common endocrine malignancy. Its incidence increasing over the last four decades. The same as the adults, papillary thyroid cancer (PTC) is the most common DTC in children. Children,especially those under 10 years of age, may not have the classic papillary morphology seen in adults. In several case series, DTC in pediatric and adolescents under 20 years of age, seems to have a different clinicopathological profile and outcome compared to adults. When histology and tumor size are controlled, children often have more advanced cancer at the time of diagnosis compared to adults, with greater regional lymph node involvement, pulmonary metastasis, and chance for recurrence. Despite extensive disease at clinical presentation, children are much less likely to die from disease. The basis for these differences between children and adults is various types of the mutations and expression of the sodium-iodine symporter. The guidelines indicate that the evaluation and treatment of thyroid nodules in children should be the same as in adults with the exceptions that ultrasound characteristics and clinical context should be used rather than size alone to identify nodules that warrant fine needle aspiration (FNA). Preoperative FNA of a hyperfunctioning nodule in a child is not warranted as long as the lesion is removed. A diffusely infiltrative form of PTC may occur in children and should be considered in a clinically suspicious gland. For both children and adults, cytopathology findings on FNA are categorized according to the Bethesda system for reporting thyroid cytopathology. Due to the apparent increased probability of malignancy among indeterminate categories nodules in children, definitive surgery (lobectomy plus isthmusectomy) for indeterminate FNA findings is recommended.Distant metastases in children are more amenable and responsive to 131-I therapy compared with adults. No studies are yet available for oral kinase inhibitors class in I-131 refractory pediatric PTC. Despite more widespread and more aggressive at presentation, children with DTC have an excellent prognosis and low mortality